# Diagnostic Performances of a Rapid Screening Tool for Detection of Psychiatric Symptomatology in an Urban Community Setting of People Who Use Drugs in France

Lionel Moulis, Laurent Michel, Philippe Trouiller, Tiffany Charmet, Flore Gruyelle, Julien Joly, Catherine Quillet, Nicolas Nagot, Hélène Donnadieu

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Lionel Moulis, Laurent Michel, Philippe Trouiller, Tiffany Charmet, Flore Gruyelle, et al.. Diagnostic Performances of a Rapid Screening Tool for Detection of Psychiatric Symptomatology in an Urban Community Setting of People Who Use Drugs in France. Journal of Dual Diagnosis, In press, 10.1080/15504263.2025.2557194. [hal-05264842](https://hal.science/hal-05264842v1)

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# Diagnostic Performances of a Rapid Screening Tool for Detection of Psychiatric Symptomatology in an Urban Community Setting of People Who Use Drugs in France

Lionel Moulis, Laurent Michel, Philippe Trouiller, Tiffany Charmet, Flore Gruyelle, Julien Joly, Catherine Quillet, Nicolas Nagot & Hélène Donnadieu

**To cite this article:** Lionel Moulis, Laurent Michel, Philippe Trouiller, Tiffany Charmet, Flore Gruyelle, Julien Joly, Catherine Quillet, Nicolas Nagot & Hélène Donnadieu (13 Sep 2025): Diagnostic Performances of a Rapid Screening Tool for Detection of Psychiatric Symptomatology in an Urban Community Setting of People Who Use Drugs in France, Journal of Dual Diagnosis, DOI: 10.1080/15504263.2025.2557194

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# Diagnostic Performances of a Rapid Screening Tool for Detection of Psychiatric Symptomatology in an Urban Community Setting of People Who Use Drugs in France

Lionel Moulis, MDª,ᵇ ID, Laurent Michel, MDᶜ ID, Philippe Trouiller, MDᶜ, Tiffany Charmet, MPHᵈ ID, Flore Gruyelle, MSᶜ, Julien Joly, MSª, Catherine Quillet, MSª, Nicolas Nagot, MD, PhDª,ᵇ ID and Hélène Donnadieu, MD, PhDª ID

ªPCCEI, University of Montpellier, INSERM, University of Antilles, Montpellier, France; ᵇClinical Research and Epidemiology Unit, CHU Montpellier, Univ Montpellier, Montpellier, France; ᶜCESP Inserm UMRS 1018, Pierre Nicole Center, Paris Saclay University, French Red Cross, Paris, France; ᵈEmerging Diseases Epidemiology Unit, Institut Pasteur, Université Paris Cité, Paris, France

## ABSTRACT

**Objective:** We aimed to evaluate the diagnostic accuracy of a rapid 9-item peer-administered questionnaire, the Quick Screening Tool (QST), to detect urgent mental health symptoms in an urban community setting in France of People who use drugs (PWUD). **Methods:** Participants were recruited through Respondant-Driven Sampling. We used modules from the Mini International Neuropsychiatric Interview as the reference standard (current major depressive episode, suicidal risk, or current psychotic disorder). We calculated the area under the curve as well as sensitivity and specificity. **Results:** Thirty-four percent of the 175 participants were assessed as in need of urgent mental care. The prevalence for depressive episode, suicidal risk and current psychotic syndrome was 11%, 19%, and 8%, respectively. The QST had an area under the curve for the detection of urgent psychiatric symptoms of 0.82. With a cutoff of 3, it had a sensitivity of 83.3% and a specificity of 64.4%. **Conclusions:** The performance of the QST in screening for urgent mental health symptoms was satisfactory. This questionnaire could be more broadly used in hard-to-reach PWUD populations in community-based interventions.

## KEYWORDS

Mental health screening;
psychiatric disorder; people who
use drugs (PWUD);
community-based interventions;
quick screening tool (QST);
urban community setting; major
depressive episode; psychotic
disorder; suicidal risk; France

People who use drugs (PWUD) are particularly at risk of psychiatric disorders. Dual diagnosis, the co-occurrence of a mental health disorder with a substance use disorder, ranges from 40 to 50% in the PWUD population, depending on the setting (Compton et al., 2007; Conner et al., 2008; Kingston et al., 2017; Schuckit, 2006). The co-occurrence of the two disorders often worsen each other's prognosis, with serious consequences at socio-professional and clinical levels, as well as for access to care in general (Couteron, 2022; Schuckit, 2006; Steger & Kashdan, 2009).

In public health settings, such as community-based interventions targeting PWUD, it has become essential to have rapid screening tools to identify people at risk of psychiatric disorders requiring urgent care. These instruments should be short, easy to use (even for non-healthcare professionals), and have good diagnostic performance. Participants who screened positive

could then be referred to a health professional for a more thorough assessment of their mental health.

Some validated questionnaires cannot be considered in this context because of their length, such as the Mini International Neuropsychiatric Interview (MINI) or the Dual Diagnosis Screening Interview (Mestre-Pintó et al., 2014; Sheehan et al., 1997). Other questionnaires such as the Self Reporting Questionnaire or the Kessler Psychological Distress Scale (Andrews & Slade, 2001; Beusenberg & Orley, 1994) cannot be used because they do not evaluate psychotic symptomatology, which is important in the context of substance use, especially with use of stimulants like methamphetamine or cocaine/crack (Tang et al., 2014; Zorick et al., 2008). Other questionnaires, such as the GAIN-SS-IDScr, the K6, the Psychiatric sub-scale of the Addiction Severity Index, or the Psychiatric Diagnostic Screening Questionnaire, are rapid and easy to administer but were only validated for people

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who use drugs in treatment-seeking contexts evaluated by professionals (Rush et al., 2013).

In this context, the Quick Screening Tool (QST) appears to be a pertinent screening questionnaire. It was developed for the DRIVE study (New York University Hai Phong Medical University Université de Montpellier & Centre for supporting Community Development Initiatives, 2018) in Hai Phong, Vietnam, and validated in a Vietnamese population of people who inject drugs recruited from the community and living in precarious conditions (Le et al., 2022). The QST is rapid, considered easy to use by members of community-based organizations, and showed satisfactory sensitivity and specificity (71% and 76%, respectively). Additionally, the QST includes assessments for psychotic symptomatology, which makes it more suitable for detecting a broader range of psychiatric symptoms that are prevalent in PWUD. However, while research has highlighted the importance of validating screening tools within the specific populations and settings where they will be applied (Castel et al., 2008), the QST has not been validated in PWUD from French cities.

Although living in a high-income country, French PWUD in urban settings are particularly vulnerable. Many of them experiencing being unhoused (Weill-Barillet et al., 2016) or are dealing with migration challenges, particularly from Eastern Europe (Tibi-Lévy et al., 2020). Furthermore, they are often characterized by polysubstance use, with crack-cocaine and heroin being particularly prevalent (Donnadieu et al., 2023). All these specific characteristics of French PWUD impact their risk of psychiatric disorders. (Cantor-Graae & Pedersen, 2013; McMahon et al., 2017; Nilsson et al., 2024; Selten et al., 2020). However, they make limited use of existing care structures designed to help them, such as French harm reduction centers (CAARUD) (Nagot et al., 2022), only 1.2% of which employed a psychiatrist in 2015 (Collard et al., 2015). In outreach programs for the most vulnerable, such as SAMU social, only 7% of teams are made up of mental health professionals (Lemarque & Chéruy, 2021). PWUD's distance from healthcare services makes the recognition of psychiatric disorders and their treatment initiation challenging, often resulting in delayed care (Ann Priester et al., 2016).

In this study, included in the Community Intervention to Eliminate HCV Among People Who Use Drugs (ICONE2) project (Clinicaltrials.gov, 2023), we aimed to analyze the diagnostic performance of the QST questionnaire in detecting psychiatric disorders requiring urgent help in a French population of

community-based PWUD, recruited through a Respondent-Driven Sampling method (RDS). We hypothesized that this peer-administered screening tool would have good discriminative capacity in this population, and that for a chosen cutoff, it could offer a sensitivity greater than 75% with a suitable specificity. We also aimed to investigate diagnostic accuracy in subgroups according to gender, since the literature suggests a higher risk of depression and suicide among women who use drugs (WWUD) (Jangal et al., 2022; Moulis et al., 2023), and in subgroups according to crack use, since the prevalence of depressive and psychotic symptoms is frequent among people who use stimulants (Karsinti et al., 2020; Miguel et al., 2018; Narvaez et al., 2014).

# Methods

## Study design

This study was conducted as a first necessary phase of the ICONE 2 study. The goal of ICONE 2 was to develop a test-and-treat approach to screening for infectious, addictive, and psychiatric disorders in PWUD with a view to rapid treatment initiation (Clinicaltrials.gov, 2023). To screen the 3200 expected participants in France (1200 in Paris, 800 in Lyon, 800 in Marseille, and 300 in Fort de France), a two-stage psychiatric screening was implemented. A first rapid screening tool, the QST, would be used to select high-risk PWUD for psychiatric disorders, who would then be offered a MINI administration. A positive MINI would then lead to a psychiatric consultation. We designed this present study to analyze the most pertinent cutoff for the first-line questionnaire, the QST, and to evaluate its associated performance.

To this end, we designed a cross-sectional diagnostic performance assessment study using a subpopulation of RDS-recruited participants from the ICONE 2 Paris center. All participants were administered the index test (QST questionnaire) by a peer worker and were also administered modules of the MINI by a health professional as a reference standard. Peer workers and health professionals were blinded to each other's results but had access to clinical information. Before the start of the RDS, the staff was trained on the protocol and Good Clinical Practices for everyone, as well as on the different study procedures according to their roles. Peer workers were trained on risk and harm reduction, therapeutic support, and questionnaire administration to ensure they fully understood the meaning of the questions and the nature of the
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expected responses and to differentiate the effects of substances from preexisting symptoms. This training was conducted through formal presentations of the protocol and procedures, as well as real-life simulations on-site with the various IT tools and supporting documents, during the two weeks preceding the center's opening. Data collection was prospective. No formative research was conducted beforehand because the investigator had the experience of a similar previous study in another French city (Donnadieu et al., 2023). This study adhered to the Standards for Reporting of Diagnostic Accuracy criteria (Cohen et al., 2016) and the Standards for Reporting of Respondent-Driven Sampling studies (White et al., 2015). Study activities occurred between October 1, 2023–January 31, 2024. The study was conducted in a setting specifically opened for the research, located outside of traditional healthcare facilities. This site was chosen for its neutrality, its proximity to neighborhoods with frequent substance use, and its provision of both inside and outside waiting areas.

## Population

All adults who declared using psychoactive substances (in addition to alcohol, tobacco, and cannabis) were eligible in the ICONE 2 study. Drug use was confirmed by a positive urine test for heroin/morphine, amphetamines, methamphetamines, ketamine, cocaine/crack cocaine, MDMA/ecstasy, cathinones, or misused medication (methadone, buprenorphine, opiates). Inability to understand the study or being under French judicial protection programs (*tutelle, curatelle, or mandat de protection*) were exclusion criteria.

Standard procedures were used to recruit our population by an RDS method (Heckathorn, 1997; Heckathorn et al., 2002). Fifteen seeds were selected with the support of local associations to be representative of the target population (PWUD active in squats/on the street, male/female, older/younger), to be at a distance from care facilities and to have extensive networks of peers (Heckathorn, 2002). Once they participated, they were given three coupons to offer to fellow PWUD and were informed about the RDS opening duration. This sampling method provides access to hard-to-reach populations and ensures that the included population is representative of the active drug-using population (Des Jarlais et al., 2016). Participants were compensated €50 euros for their participation and received €20 euros for each eligible participant they helped to recruit to the study. To prevent repeat participation in the research, simple dissuasive biometric measurements were taken at

inclusion as soon as consent was signed, including forearm circumference and tip of elbow to middle finger. A specific control program was set up in the database, allowing duplicate biometric measurements to be flagged as soon as the data were entered.

In this sub-study, we enrolled all consecutive first participants until we reached the required sample size. No changes in study procedures during data collection were observed.

## Outcomes

The Quick Screening Tool is a nine-item questionnaire developed for the DRIVE study in Hai Phong, Vietnam. It is designed to be administered quickly, requiring only two hours of training and can be administered by non-health professionals. This questionnaire was used to identify PWUD in need of urgent mental care in a psychiatrically underserved environment in a low to middle income country. It consists of: (i) four questions from the Patient Health Questionnaire-4 (PHQ-4) questionnaire covering anxiety and depression ranging from 0 to 3 on a Likert-scale (Kroenke et al., 2009), (ii) two questions on suicide risk ranging from 0 (no) to 2 (yes), (iii) three questions on psychotic symptoms ranging from 0 (no) to 2 (yes). The questions on depression and anxiety covered the last two weeks, while the questions on suicidal risk and psychotic disorders covered the entire lifespan. The details of these questions have been described elsewhere (Le et al., 2022). The QST score was calculated as the sum of all these questions and ranges from 0 to 22, with higher scores indicating a higher risk of psychiatric symptoms. A cutoff score of 2 was originally set for the Vietnamese PWUD population. We designed the study to identify a different cutoff for the French population that would maximize the sensitivity and Negative Predictive Value (NPV) in the context of a first-line screening test.

The reference standard for the presence of psychiatric symptoms requiring urgent help was a composite criterion comprising suicidal risk, current major depressive episode, and current psychotic syndrome. These elements were assessed via the MINI questionnaire using the major depressive episode, suicidality, and psychotic disorder modules (Sheehan et al., 1997). The components were chosen to identify people in need of urgent psychiatric help. They corresponded to the domains explored by the QST, with the exception of anxiety disorders, which would have required more time from the investigators and participants. The MINI was chosen as the reference standard because of its good performance, speed of
administration and widespread use in both the general population and among PWUD (UNODC, 2022).

In an exploratory sensitivity analysis, we analyzed the diagnosis performance of the QST to detect current urgent psychiatric symptomatology, in particular suicidal risk (a low suicidal risk was not deemed sufficient to be considered as urgent psychiatric symptomatology, as it could be a remnant of a past suicidal crisis, with the question “Have you ever made a suicide attempt in your life?” being associated with a low risk of suicide) (Sheehan et al., 1997).

Participants' socio-demographic and major clinical information were collected in questionnaires to describe the population. Participants were asked about their personal network size ("How many people do you know [meaning that you know at least the first or last name, or the pseudonym], who currently use psychoactive substances?"). They were also asked about the recruiter-recruit relationship ("Does the person who gave you the coupon know your name?" and "Do you know the name of the person who gave you the coupon?").

## Statistics

### Sample size

In order to have a precision (half-width of the 95% confidence interval) of no more than +/- 10% in estimating both sensitivity and specificity, assuming both to be 75% (Le et al., 2022) and assuming a prevalence of psychiatric disorders of 45% (Kingston et al., 2017), we decided to include 175 participants.

### Statistical analysis

A flowchart was used to illustrate the various selection steps. Population characteristics were described using mean (SD) or median (Q1-Q3) for continuous data, and frequency (percentage) for discrete variables. To describe the prevalence of psychiatric disorder and their 95% confidence interval, Gile's successive sampling (SS) estimator was used (Gile, 2011).

Undetermined results or missing data for both the index test and the reference standard would have been imputed to lower performance of the analyzed criterion if present (e.g., sensitivity, specificity, NPV, PPV, etc.).

A Receiver Operating Characteristic (ROC) curve was constructed to evaluate the discriminatory ability of the QST score. The area under the curve (AUC) was calculated by the variance calculation method of Delong et al. (DeLong et al., 1988) and the Sun and Xu algorithm (Sun & Xu, 2014).

We calculated the diagnostic performances of the QST score for the detection of urgent psychiatric symptoms (sensitivity, specificity, positive predictive value, negative predictive value) and their respective bootstrapped 95% confidence intervals at a cutoff point determined by clinical expertise.

The same approach was used to evaluate the diagnostic performances of the QST in the sensitivity analysis and in subgroup analyses according to gender and self-reported crack cocaine use in the last month.

To compare the characteristics of the study population with those of the Vietnamese study population, student's t-tests were used for quantitative variables, and Chi-square or Fisher's exact tests for qualitative variables.

Seeds were treated like any other participant. All statistics were performed using R 4.1.3 with 95% confidence intervals and two-tailed statistical tests with alpha set at 5%. RDS analysis was performed using the RDS r package (Handcock et al., 2024).

## Ethics

None of the peer workers knew the real names of the participants, who were called by the first names or pseudonyms they had chosen at the time of inclusion. Participants diagnosed with a psychiatric disorder requiring therapy were offered on-site psychiatric care if they were not already receiving treatment.

All participants signed a written consent to participate after a complete discussion of the study. This study protocol was reviewed and approved by the Persons Protection Committee of Ouest II, approval number 23.01718.000166. The study was conducted in accordance with the Helsinki declaration. The clinical trial was registered before patient enrollment [NCT05794646].

## Results

### Population

The first 175 participants of the ICONE 2 study at the Paris center were included and underwent both the QST and the MINI questionnaire (shown in Figure 1). The median age was 45, with the youngest being 20 and the oldest 70 years old. Twenty (11.4%) participants were women (Table 1). About half of the participants were from France, a third were from Eastern Europe and a tenth were from Western Europe (excluding France). Only one-sixth of the participants were married or in a civil partnership. Just under half of the population had a permanent home, and 28%
<figure><img src="image_16.png" /></figure>

<figure><img src="image_17.png" /><figcaption>**Figure 1.** Planned enrollment and flowchart of the selection process.</figcaption></figure>

were unhoused. In terms of health care use, a third had no health insurance and 7% of participants had consulted a mental health facility in the past year (Figure 1).

## Substance use

Of the 175 participants, 52 (27%) had only one of the molecules tested in their urine. Three participants were positive for 4 to 5 out of the 9 substances tested. The vast majority of participants (81%) had cocaine or crack cocaine in their urine sample. Methadone was detected in 53% of PWUD, heroin in 42%, and buprenorphine in 22%. Cocaine/crack cocaine was used with methadone and heroin by 24% of the population, alone by 20%, and with methadone alone for 15% (Figure 2).

## Psychiatric outcomes

Twenty-four participants (13.7%) had a current major depressive episode, 48 (27.4%) had a suicidal risk (low, moderate, or high) and 16 (9.1%) had a current psychotic syndrome. Using the Gile's SS estimator, the

prevalence for depressive episode, suicidal risk, and current psychotic syndrome was 10.9% (95% CI [3.4%, 18.4%]), 19.2% (95% CI [11.2%, 27.2%]) and 7.9% (95% CI [0.5%, 15.2%]), respectively. Their design effect (DE) was respectively 2.61, 1.89, and 3.38. Overall, the standard reference for urgent psychiatric symptomatology was positive in 60 of 175 participants (34.4%). Using the SS estimator, its prevalence was 27.4% (95% CI [16.8%, 38.0%]) with a DE of 2.66. The median QST score was 3 (Q₁–Q₃: 0–6) and ranged from 0–22.

No patient had an undetermined index test or reference standard and there were no missing data for either outcome (Figure 1). The QST and MINI questionnaires were administered to each participant on the same day. No adverse events occurred during the conduct of either questionnaire.

The area under the curve for the QST to detect urgent psychiatric disorder was 0.82 (95% CI [0.76, 0.89]) (Figure 3a). The sensitivity and specificity associated with different QST cutoffs are presented in Table 2. We chose a cutoff of three, favoring sensitivity (screening tool), which was positive in 92 (52.8%) participants. This corresponded to a
<table><caption>**Table 1.** Participants characteristics at baseline.</caption><thead><tr><th>Variable</th><th>Population (n=175)</th></tr></thead><tbody><tr><td>Age (years), Median (Q<sub>1</sub>; Q<sub>3</sub>)</td><td>45 (38; 50)</td></tr><tr><td>Gender</td><td></td></tr><tr><td>Male</td><td>154 (88.00)</td></tr><tr><td>Female</td><td>20 (11.43)</td></tr><tr><td>Not declared</td><td>1 (0.57)</td></tr><tr><td>Marital Status</td><td></td></tr><tr><td>Single</td><td>98 (56.00)</td></tr><tr><td>Separated</td><td>50 (28.57)</td></tr><tr><td>Married/Civil partnership</td><td>22 (12.57)</td></tr><tr><td>Widower</td><td>4 (2.29)</td></tr><tr><td>Prefer not to say</td><td>1 (0.57)</td></tr><tr><td>From</td><td></td></tr><tr><td>France</td><td>85 (48.57)</td></tr><tr><td>Eastern Europe</td><td>53 (30.29)</td></tr><tr><td>Western Europe (excluding France)</td><td>19 (10.86)</td></tr><tr><td>Maghreb</td><td>11 (6.29)</td></tr><tr><td>Sub-Saharan Africa</td><td>5 (2.86)</td></tr><tr><td>South Asia</td><td>2 (1.14)</td></tr><tr><td>Living Location</td><td></td></tr><tr><td>In Paris</td><td>159 (90.86)</td></tr><tr><td>Outside of Paris</td><td>16 (9.14)</td></tr><tr><td>Living Conditions</td><td></td></tr><tr><td>Permanent (autonomous/with relatives/institutions/hotel)</td><td>80 (45.71)</td></tr><tr><td>Tent, street</td><td>49 (28.00)</td></tr><tr><td>Temporary (with relatives/ institutions)</td><td>27 (15.43)</td></tr><tr><td>Squat, truck</td><td>17 (9.71)</td></tr><tr><td>Other/Prefer not to say</td><td>2 (1.14)</td></tr><tr><td>Has health insurance?</td><td></td></tr><tr><td>No</td><td>59 (33.71)</td></tr><tr><td>Yes</td><td>116 (66.29)</td></tr><tr><td>Consulted a mental health care structure in the last year?</td><td></td></tr><tr><td>No</td><td>162 (92.57)</td></tr><tr><td>Yes</td><td>13 (7.43)</td></tr><tr><td>Less than once a month</td><td>8 (61.54)</td></tr><tr><td>Once or more a month</td><td>3 (23.08)</td></tr><tr><td>Once or more a week</td><td>2 (15.32)</td></tr><tr><td>Alcohol Use</td><td></td></tr><tr><td>Never</td><td>60 (34.29)</td></tr><tr><td>Less than once a week</td><td>47 (26.86)</td></tr><tr><td>At least once a week</td><td>68 (38.86)</td></tr><tr><td>Tobacco Use</td><td></td></tr><tr><td>No</td><td>7 (4.00)</td></tr><tr><td>Yes</td><td>168 (96.00)</td></tr><tr><td>Cannabis Use</td><td></td></tr><tr><td>No</td><td>53 (30.29)</td></tr><tr><td>Yes</td><td>121 (69.14)</td></tr><tr><td>Prefer not to say</td><td>1 (0.57)</td></tr></tbody></table>

Note. Data are presented in frequency (%) unless otherwise noted. There were no missing data for the variables presented.

sensitivity of 83.3% (95% CI [73.3%, 91.7%]) and a specificity of 64.6% (95% CI [54.8%, 73.0%]).

## Sensitivity analysis

With a reference test defined as a composite of moderate to high suicidal risk, current major depressive episode, and current psychotic syndrome, only 36 of the 175 participants (20.6%) were positive. The QST was able to correctly discriminate 83% of participants (95% CI [76%, 90%]) (Figure 3b). The cutoff analysis was reasonably equivalent to the other reference test definition, with a selected cutoff of 3, corresponding

to a sensitivity of 88.9% (95% CI [77.8, 92.2]) and a specificity of 57.6% (95% CI [48.9, 66.2]).

## Subgroup analysis

One person did not report gender and was excluded from the gender subgroup analyses. The prevalence of suicidal risk, current major depressive episode, or current psychotic syndrome was significantly higher in women (15/20, 75.0%) compared to men (44/154, 28.6%), *p* < .01. Women had a significantly higher QST score than men (*p* = .01). A histogram of the QST score distribution by gender is shown in Figure 4a. The AUC for women was 0.92 (95% CI [0.78, 1.00]), with a sensitivity and specificity of 86.7% (95% CI [68.8%, 100.0%]) and 80.0% (95% CI [40.0%, 100.0%]), respectively, for a cutoff of 3. For men, the QST showed an AUC of 0.80 (95% CI [0.73, 0.88]) and a sensitivity and specificity of 81.8% (95% CI [70.5%, 93.2%]) and 63.6% (95% CI [54.6%; 72.7%]), respectively, for the same cutoff (shown in Table S1).

PWUD who used crack cocaine in the last month tended to have a higher frequency of psychiatric symptoms on the MINI, although this was not statistically significant. The QST score was significantly higher among people who used crack recently with a median of 3.5 (Q<sub>1</sub>-Q<sub>3</sub>: 1-7) compared to 1 (Q<sub>1</sub>-Q<sub>3</sub>: 0-2), *p* < .01. A histogram of the QST score according to the recent crack use is shown in Figure 4b. The AUC was 0.83 (95% CI [0.76, 0.90]) for people who used crack recently and 0.73 (95% CI [0.50, 0.97]) for the others. Diagnostic performances according to QST cutoff are shown in Table S2.

## Discussion

### Key findings

In this sample of 175 people who actively use illicit psychoactive drugs (disregarding cannabis) from an urban setting in Paris, France, the prevalence of suicidal risk, major depressive episode, and psychotic syndrome, as measured by combined MINI modules, was more than one third. This prevalence was alarmingly higher among women, reaching three-quarters. Excluding those with a low risk of suicide, one-fifth of the population still tested positive.

Identifying individuals in need of urgent and rapid psychiatric treatment was crucial in the context of the ICONE-2 study. The QST questionnaire effectively discriminates between PWUD who need psychiatric care and those who do not. At the chosen cutoff of
<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /><figcaption>**Figure 2.** Density histogram and intersection plot of investigated substances in urine at baseline.</figcaption></figure>

Note. Not all intersections are shown due to space limitations

3, its sensitivity was excellent while maintaining an acceptable specificity.

## Adapting the QST to local contexts

In the Vietnamese PWID population, where the QST questionnaire was developed, the AUC was similar to that in our population, but the chosen cutoff of 2 resulted in lower sensitivity (71%) and higher specificity (76%). Overall, compared with the Vietnamese PWID in the study, our participants were significantly different across several

characteristics: they were older (44.5 ± 9.3 vs 40.3 ± 8.7 years), less likely to be male (88% vs 95%), less likely to be living in a couple (13% vs 40%), and more likely to have a health insurance (66% vs 40%). Furthermore, while all Vietnamese participants were selected if they had needle marks and heroin or methamphetamines in their urine, only half of our population tested positive for heroin, and about a quarter reported using heroin in the last month. In Paris, PWUD were much less likely to have used methamphetamines in the last month compared to those in Hai Phong (5% vs 44%).
<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /></figure>

<figure><img src="image_22.png" /><figcaption>**Figure 3.** (a) ROC curve of the QST score for detection of psychiatric disorder. (b) ROC curve of the QST score for detection of current psychiatric disorder.</figcaption></figure>
<figure><img src="image_23.png" /><figcaption>**Table 2.** Sensitivity, specificity, PPV and NPV for different thresholds of QST for detection of psychiatric disorder.</figcaption></figure>

<table><thead><tr><th>QST</th><th>Sensitivity<br>(95% CI), %</th><th>Specificity<br>(95%CI), %</th><th>PPV (95%<br>CI), %</th><th>NPV (95% CI), %</th></tr></thead><tbody><tr><td colspan="5"><em>To detect any suicidal risk or current MDE or current psychotic disorder</em></td></tr><tr><td>≥ 1</td><td>96.67 (91.67;<br>100.00)</td><td>37.39 (28.70;<br>46.09)</td><td>44.53 (51.13;<br>48.36)</td><td>95.74 (88.88;<br>100.00)</td></tr><tr><td>≥ 2</td><td>93.33 (86.67;<br>98.33)</td><td>54.78 (45.22;<br>63.48)</td><td>51.85 (46.90;<br>57.58)</td><td>94.20 (88.06;<br>98.55)</td></tr><tr><td>≥ 3</td><td>83.33 (73.33;<br>91.67)</td><td>64.35 (54.78;<br>73.04)</td><td>55.06 (48.94;<br>62.22)</td><td>88.24 (81.82;<br>93.98)</td></tr><tr><td>≥ 4</td><td>70.00 (58.33;<br>81.67)</td><td>71.30 (63.48;<br>79.13)</td><td>56.13 (48.10;<br>64.79)</td><td>82.00 (76.15;<br>87.88)</td></tr><tr><td>≥ 5</td><td>66.67 (55.00;<br>78.33)</td><td>80.87 (73.91;<br>87.83)</td><td>64.71 (55.56;<br>75.00)</td><td>82.30 (76.92;<br>87.50)</td></tr><tr><td>≥ 6</td><td>58.33 (45.00;<br>70.00)</td><td>86.96 (80.00;<br>93.04)</td><td>70.21 (59.52;<br>81.63)</td><td>80.00 (75.00;<br>84.87)</td></tr><tr><td>≥ 7</td><td>45.00 (31.67;<br>58.33)</td><td>91.17 (86.96;<br>96.52)</td><td>75.00 (62.50;<br>88.57)</td><td>76.22 (72.41;<br>80.58)</td></tr><tr><td colspan="5"><em>To detect moderate to serious suicidal risk or current MDE or current psychotic disorder</em></td></tr><tr><td>≥ 1</td><td>100.00<br>(100.00;<br>100.00)</td><td>32.37 (25.16;<br>40.29)</td><td>27.69 (25.53;<br>30.25)</td><td>100.00<br>(100.00;100.00)</td></tr><tr><td>≥ 2</td><td>97.22 (91.67;<br>100.00)</td><td>47.48 (39.55;<br>55.40)</td><td>32.41 (28.93;<br>36.73)</td><td>98.55 (95.16;<br>100.00)</td></tr><tr><td>≥ 3</td><td>88.89 (77.78;<br>97.22)</td><td>57.55 (48.92;<br>66.19)</td><td>35.23 (30.39;<br>40.74)</td><td>95.35 (90.91;<br>98.84)</td></tr><tr><td>≥ 4</td><td>69.44 (52.78;<br>83.33)</td><td>64.03 (55.40;<br>71.94)</td><td>33.33 (26.56;<br>40.85)</td><td>89.10 (83.81;<br>94.12)</td></tr><tr><td>≥ 5</td><td>69.44 (52.78;<br>83.33)</td><td>73.38 (66.19;<br>80.58)</td><td>40.35 (32.20;<br>50.00)</td><td>90.35 (95.83;<br>84.74)</td></tr><tr><td>≥ 6</td><td>69.44 (52.78;<br>83.33)</td><td>82.01 (75.54;<br>87.77)</td><td>50.00 (40.00;<br>61.22)</td><td>91.27 (87.12;<br>95.24)</td></tr><tr><td>≥ 7</td><td>58.33 (41.67;<br>75.00)</td><td>89.21 (84.17;<br>94.24)</td><td>58.43 (45.24;<br>73.17)</td><td>89.21 (85.42;<br>93.18)</td></tr></tbody></table>

Note. PPV = Positive Predictive Value; NPV = Negative Predictive Value; CI = Confidence Interval. These were calculated with observed prevalence of 34.3% for the first rows and 20.6% for the last rows.

Differences between the two populations could also be explained by cultural differences and notably by variations in symptom expression between the two areas. For instance, it has been shown that German and Vietnamese psychiatric outpatients in Germany differed in their symptoms severity assessed by the PHQ (Dreher et al., 2017). In Asian settings, the expressiveness of depressive symptoms has been shown to vary: depressed people from Low and Middle Income Countries show less mood-related symptoms, which are mainly measured by the QST, and more somatic symptoms (Chee et al., 2015). Psychotic symptoms may also vary by culture, as shown in the United Kingdom (Heuvelman et al., 2018), which could be explained by specific questions on paranoia for instance.

In general, the prevalence of urgent psychiatric disorders in our study was similar to that found in the Vietnamese PWUD study (34.4% vs 30.6%). Compared with other studies, the prevalence of psychiatric disorders was lower. However, differences in recruitment settings, psychiatric disorders, tools evaluated, and temporality (current vs lifetime) limit

comparisons with the literature. In particular, we did not assess anxiety, personality or post-traumatic stress disorder although these are among the most common comorbidities in PWUD (Casadio et al., 2014; Driessen et al., 2008; Grant et al., 2004).

## Women

Although the QST seemed to offer similar performances regarding gender, we observed an alarming rate of psychiatric disorders among women, similar to studies assessing WWUD in drug treatment or harm reduction services across five European regions (Tirado-Muñoz et al., 2018). The life trajectories of women who use drugs can involve trauma, violence, and sexual risks (Jauffret-Roustide et al., 2008), leading to depressive disorders (Magnus et al., 2013; Sordo et al., 2012), anxiety disorders (Beattie et al., 2020; Frem et al., 2017), and suicide risk (Jangal et al., 2022). This highlights the need to specifically target WWUD in tailored interventions. Dedicated screening would be a first step in this urgent process, with interventions near where WWUD live or near sex work sites (Marchand et al., 2012). These gender-specific outreach actions could reduce structural barriers to accessing harm reduction services, which are particularly frequent among WWUD. Regarding care, professionals should focus on specific issues affecting WWUD's mental health, such as anxiety, low self-esteem, shame, depression, gender-based violence, and sexual assault (Motyka et al., 2022). To enhance the effectiveness of treatment, gender-specific care should be encouraged in environments that are welcoming, non-judgmental, supportive, and physically and emotionally safe (Arpa, 2017). For instance, mixed-gender CAARUDs often favor male users, resulting in limited-service utilization by women due to fear of encountering violence and gendered expectations. Women-only CAARUD offer a safer and more supportive environment, enabling women to access services without fear of violence or judgment (Coppel & Perrin, 2024).

The high prevalence of psychiatric disorders among women in our study should be interpreted with caution due to the higher number of males in the study population. Future research in the ICONE-2 project will further evaluate the link between gender and psychiatric disorders.

## Choosing the cutoff

The aim of our study was to minimize false negatives as much as possible (i.e. people who test negative on
<figure><img src="image_24.png" /></figure>

<figure><img src="image_25.png" /><figcaption>**Figure 4.** (a) Density histogram of the QST score according to the gender. (b) Density histogram of the QST score according to crack cocaine use in the last month.</figcaption></figure>
<figure><img src="image_26.png" /></figure>

the QST but actually have a psychiatric disorder). The number of false positives was not a major concern due to our multi-line screening approach—individuals with a positive QST questionnaire would undergo a MINI assessment regardless.

In this context, we chose a cutoff that best optimizes NPV and sensitivity (Trevethan, 2017). It should be noted that in other contexts where the QST might be used, different cutoffs could be used.

## Limitations

Several limitations need to be addressed. First, the three questions on psychotic symptoms in the QST are derived from the MINI questionnaire, which served as our standard reference, as they both explore the same Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria (American Psychiatric Association, 2013). This incorporation bias may have led to an overestimation of sensitivity and specificity, as participants were likely to provide consistent answers to the three common questions. To the best of our knowledge, there is no statistical way to adjust for this bias (Karch et al., 2016). However, the two questionnaires were administered by different raters (peer workers for the QST and health professionals for the MINI), who were blinded to each other's results. In addition, the phrasing of answers differed, as health professionals were instructed, according to the MINI, to assess responses subjectively for any “bizarre” answers that reflected inappropriate perceptions. When analyzed for concordance, agreement between results from the QST and MINI regarding these three questions varied from fair to moderate, as Cohen's Kappa were 0.28 (95% CI [0.10, 0.45]) for the belief that people were spying on them, 0.50 (95% CI [0.27, 0.72]) for the belief that someone was reading their mind, and 0.43 (95% CI [0.22, 0.64]) for hearing things other people could not hear, showing that the magnitude of this bias is limited.

We also chose the MINI interview, a widely used tool among PWUD with good diagnostic performance, as our standard reference. It should be noted that it may be considered as an imperfect gold standard, with itself a sensitivity and a specificity of 95% and 84%, respectively, in the diagnosis of depression according to international criteria (Pettersson et al., 2015). It constitutes, however, one of the best diagnostic tools available.

The psychiatric disorders we assessed via MINI were limited to psychotic disorders, depression, and suicidal risk. From a clinical and epidemiological point of view, it would have been interesting to

identify other psychiatric disorders as well, such as anxiety disorders, post traumatic episodes, and personality disorders, which are common in this population (UNODC, 2022). However, as a compromise between comprehensiveness and acceptability, we decided to restrict screening to psychiatric disorders requiring immediate treatment. Depressive and psychotic disorders were screened due to their association with suicide risk, as highlighted in a recent review where they were identified as the two most common mental health-related risk factors for death by suicide among PWUD (Devin et al., 2023). Furthermore, PWUD with psychotic symptoms experience a higher risk of self-injury and all-cause mortality (Correll et al., 2022; Güney et al., 2020).

A sample size of 175 participants was chosen to assess acceptable estimates of performance indices in terms of precision, while maintaining the feasibility of a MINI assessment for all. Due to a lower than expected prevalence of psychiatric disorders (34% vs 45%), precision around sensitivity was lower than expected for cutoffs close to the expected value of 75%. However, given that the chosen threshold offers greater sensitivity than expected and less specificity than anticipated, the precision is maintained in relation to what was expected (i.e. +/- 10%). Furthermore, we must emphasize that the subgroup analyses are exploratory in nature and that the study was not powered to provide sufficient precision in these analyses. These results should therefore be taken with caution.

In addition, it is possible that our population was not entirely representative of the PWUD of Paris, France, as we decided to enroll the first participants in the RDS, including seeds. The goal of the RDS recruitment method is to have a sample that is representative of the target population at the end of inclusion. Participants enrolled in this study were more likely to be from France and more likely to be living in permanent housing compared to those subsequently recruited at the ICONE-2 Paris center (Table S3). It should also be noted that PWUD from Paris may not be representative of participants from other cities in metropolitan France or overseas. Nevertheless, the organization of the ICONE-2 study required a rapid analysis of the diagnostic performances of the QST.

## Implications and gaps in research

In this first French validation of the QST questionnaire among community-based PWUD, we found that the QST performs well for the chosen cutoffs. It would be interesting to test the questionnaire in other
<figure><img src="image_27.png" /></figure>

settings, such as among patients of addiction treatment facilities or inmate populations. Indeed, the literature on psychiatric disorders in these specific populations is either scarce or outdated (European Monitoring Center for Drugs and Drug Addiction, 2015). Furthermore, future research should include the assessment of anxiety disorders, among other psychiatric disorders, to gain a more comprehensive view of the QST's performance in screening for any psychiatric disorder.

The QST questionnaire was generally well understood and used by peer workers and was well received by participants. This opened up discussions about the psychiatric risks of drug use and mental health with participants who sometimes did not feel concerned by these issues. In this manner, and in addition to offering rapid and sensitive screening for psychiatric pathologies, the QST questionnaire facilitated the administration of the MINI or psychiatric evaluation by preparing participants for these issues. Moreover, the peer workers quickly understood the importance of referring people with a high score. In this context, the QST was used in two ways. First, as a binary measure (indicating whether a score was at or above a specific cutoff), and second, as a continuous measure to indicate the severity of the situation and the urgency of intervention based on the score.

The questionnaire could be useful for any trained caregiver who is not a mental health professional and could also be utilized for test-and-treat approaches within community settings, and not necessarily by healthcare professionals. Screening for psychiatric disorders in a systematic manner could particularly benefit high-risk population such as PWUD. This could enable rapid intervention upon the identification of psychiatric disorders. Consequently, this approach aligns closely with the SBIRT model (Screening, Brief Intervention, and Referral to Treatment), which involves screening, a brief intervention, and referral to appropriate care (Thoele et al., 2021). In high-income settings like France, brief interventions and referrals can be particularly beneficial due to the availability of healthcare infrastructure and resources, such as Medical-Psychological Centers. These settings provide ideal opportunities for early intervention with at-risk populations before more severe consequences occur (Cimini & Martin, 2020).

## Statement of ethics

This study protocol was reviewed and approved by the Persons Protection Committee of Ouest II, approval number 23.01718.000166. All participants signed a written consent

to participate in the study. The clinical trial was registered before patient enrollment [NCT05794646].

## Author contributions

LiM: Conceptualization, Data Curation, Formal analysis, Methodology, Visualization, Writing – Original Draft. LaM: Conceptualization, Investigation, Supervision, Writing – Review and Editing. PT: Conceptualization, Investigation, Supervision, Writing – Review and Editing. TC: Project Administration, Writing – Review and Editing. FG: Project Administration, Writing – Review and Editing. JJ: Data Curation. CQ: Project Administration, Writing – Review and Editing. NN: Conceptualization, Methodology, Supervision, Writing – Review and Editing. HD: Conceptualization, Funding Acquisition, Project Administration, Supervision, Writing – Review and Editing.

## Disclosure statement

HD receives compensation as expertise and oral communications for AbbVie, Gilead and Etypharm company. Other authors have no conflicts of interest to declare. This article is part of the Community Intervention to Eliminate HCV among People Who Use Drugs research project registered on clinicaltrials.gov [NCT05794646].

## Funding

This study was funded by the French ANRS, Emerging Infectious Diseases [ANRS 0336s]. The funder had no role in the design, data collection, data analysis, and reporting of this study.

## ORCID

Lionel Moulis ID http://orcid.org/0000-0001-7873-3245

Laurent Michel ID http://orcid.org/0000-0002-2000-7838

Tiffany Charmet ID http://orcid.org/0000-0003-4012-4940

Nicolas Nagot ID http://orcid.org/0000-0002-3493-2821

Hélène Donnadieu ID http://orcid.org/0000-0001-8398-812X

## Data availability statement

The data that support the findings of this study are available from the corresponding author, [LM], upon reasonable request. Data for all participants in the Paris center and other centers are embargoed until the end of the last RDS in the last center.

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