The Taste-Mood Diagnostic Study

Study Overview
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Brief Summary
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The study will be looking at whether a taste test device can be used as a diagnostic aid for depression. Taste tests will be carried out before and after first use of an antidepressant (prescribed by the patient's GP) and then again a month later a further taste test will be conducted. The results of these tests will be assessed to see if they correlate with the outcome of validated mood questionnaires carried out at the first and second visits.

Detailed Description
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Research shows a clear link between taste sensitivity and depression, based on chemistry shared by the tongue and the brain. (Heath, T.P., Melichar, J.M., Nutt, D.J., Donaldson L.F. (2006) Human taste thresholds are modulated by serotonin and noradrenaline). The aim of this study is to investigate the use of a taste test in the diagnosis of depression and to predict drug effectiveness. A device is being developed to automate the taste test with different concentrations of salt, sweet, bitter and sour solutions. A test is carried out before and after ingesting a probe drug (first prescribed antidepressant) to assess change in taste. Standard validated questionnaires are used to assess mood on the day the first antidepressant is ingested and one month later. The first 30 participants will have taste tests conducted out not only via the device described above, but also via a paper flow chart which similarly determines the order in which taste solutions are presented to the participant to determine taste acuity. The study is a single centre, open label study using the patient's prescribed antidepressant as a probe with the primary objective of replicating previous results obtained, without the use of a device, and using paroxetine. The study is powered to test 240 patients with the provision built in to the protocol for an interim analysis after 120 patients have been tested. This will lead to the generation of a robust diagnostic algorithm. Patients will be followed up for repeat taste testing after 28 days (±7 days) of usual clinical care, and follow up questionnaires will be completed at that visit. Patients will be asked to complete a feedback questionnaire about their user experience and satisfaction with treatment alone.

Official Title
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Using a Diagnostic Taste Test as a Surrogate Biomarker to Predict Drug Effectiveness in Patients With Depression (MDD)

Conditions
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Depression

Intervention / Treatment
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* Diagnostic Test: Taste test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with a diagnosis of previously untreated Major Depressive Disorder (MDD) of at least 3 weeks duration or new or recurrent MDD untreated before this episode (patients who have previously received treatment for MDD must have stopped taking antidepressant medication at least six weeks prior to entering the trial); Patients requiring pharmaceutical intervention as a treatment for MDD; Not suffering from any significant other mental or physical illness, such as confirmed psychosis, or end of life care. Receiving stable medical therapy for 30 days or longer before screening assessments; Be willing and able to comply with all visits and study related procedures; Not infected with coronavirus or needing to self-isolate Understands the study requirements and the treatment procedures and is able to provide written informed consent. Exclusion Criteria: Already on antidepressant medication; Known or suspected hypersensitivity or intolerance to any probes, or any of their excipients; Relevant history or presence upon clinical examination, of cardiac, ophthalmologic, gastro-intestinal, hepatic, or renal disease or other condition known to increase risk of side effects of the probe drugs. This exclusion criterion is determined by the Site Investigator; Have a history or presence of neurological or confounding psychiatric conditions (such as stroke, traumatic brain injury, epilepsy, space occupying lesions, multiple sclerosis, Parkinson's disease, vascular dementia, transient ischemic attack, or schizophrenia), Patients with a diagnosis of chronic pain. Participation in another trial concurrently or within 30 days preceding enrolment that is deemed to interfere with this trial; Patients who are pregnant, or who are likely to become pregnant, will be excluded from the trial, as will breastfeeding mothers; Patients using supplements containing psychoactive herbs (for example St Johns Wort or 5-HTP (5-Hydroxytryptophan, also known as oxitriptan); Patients regularly using psychoactive stimulants and recreational drugs (for example MDMA (ecstasy/ methyl enedioxy methamphetamine), amphetamine, LSD (lysergic acid diethylamide), cocaine); Patients infected with coronavirus, or who are advised to self-isolate Patients who are unable or unwilling to comply with study procedures.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: Taste tests will be undertaken, in order to establish taste thresholds. Observation of changes in taste thresholds with change in mood following antidepressant treatment may help develop a diagnostic test for depression. The taste test will not assist diagnosis of depression for the group of participants in this study, so the primary purpose is not described as diagnostic.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Taste test<br>Participants will be presented with a series of tastants of 4 different modalities (sweet, salt, sour, bitter) of 9 different concentrations in pseudo-random order. The threshold at which each participant reliably identifies the taste is determined for each tastant. Mood Questionnaires will be used to determine whether a participant is clinically depressed. | Diagnostic Test: Taste test<br>* A device is used to present a pseudo-randomised series of taste solutions to the participant for identification, in order to establish taste thresholds.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in taste threshold with antidepressant treatment | Change in taste threshold measures (sweet, salt, bitter, sour) between baseline and post-probe(s) at day 1 and 28 days after antidepressant treatment is initiated is assessed with the assistance of a taste test device. | 4-6 weeks (per patient) | 
| Change in mood (assessed by score on the Beck Depression Inventory) with antidepressant treatment | Change in mood (assessed by score on the Beck Depression Inventory (BDI)) with antidepressant treatment is assessed. BDI scores may range from 0-63, where 0 demonstrates the lowest depression score and 63 the most severe depression. | 4-6 weeks (per patient) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in mood with antidepressant treatment, measured by the Clinical Global Impression Scale (CGI scale) | Changes in scores on the Clinical Global Impression scale, as assessed by the participant's general medical practitioner is recorded. This scale ranges from 0-7, where 0 is the least severely ill and 7 the most severely ill. | 4-6 weeks (per patient) | 
| Change in mood with antidepressant treatment, measured by the Patient Health Questionnaire 9 (PHQ9) | Change in mood with antidepressant treatment, measured by the Patient Health Questionnaire 9 (PHQ9). PHQ9 scores range from 0-27, where 0 is the score for the least depressed patients and 27 the most severely depressed patients. | 4-6 weeks (per patient) | 
| Change in mood with antidepressant treatment, measured by the Hospital Anxiety and Depression scale (HADS) | Change in mood with antidepressant treatment, measured by the Hospital Anxiety and Depression scale (HADS). HADS scores for depression range from 0-21, where 0-7 is normal, 8-10 borderline and 11+ indicates clinical depression | 4-6 weeks (per patient) | 
| Change in mood with antidepressant treatment, measured by the Quick Inventory of Depressive symptomatology (QIDS) | Change in mood with antidepressant treatment, measured by the Quick Inventory of Depressive symptomatology (QIDS). Scores for QIDS range from 0-27, where 0 indicates no symptoms of depression and 27 indicates the most severe depression. | 4-6 weeks (per patient) | 
| Validation of diagnostic algorithm, comparing the sequence of taste testing determined by software with the algorithm described in the software specification. | A computerised algorithm will be used to direct the taste test to assess taste sensitivity. The algorithm has been developed to direct the taste test, indicating which taste solutions should be presented to the participant in which order. Every solution presented is recorded, along with answers given. These will be examined after testing to validate the code's ability to follow the algorithm created and properly determine taste thresholds. | 12 months (duration of trial) | 
| User assessment of ease of use of the device and testing process. | User views on ease of use of the device and testing process will be collected. Users will be asked to give ease of use a score from 1-5, where 1 is very easy and 5 is very difficult. Participants will also be asked whether they would use the taste test again. | 4-6 weeks (per patient) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Depression, Diagnostic aid, Taste