History of Suicidal Behaviour and Analgesic Use in Community-Dwelling Elderly
Authors: Emilie Olié, Philippe Courtet, Vanessa Poulain, Sébastien Guillaume, Karen Ritchie, Sylvaine Artero
Journal: Psychotherapy and Psychosomatics (2013)

One million people worldwide kill themselves every year and nearly 20 times that number attempt suicide. According to the ‘stress-vulnerability' model, vulnerable patients will perform suicidal acts when exposed to stressors such as psychiatric illness and environmental factors. Vulnerability corresponds to a stable trait defined in terms of genetic, biological and cognitive abnormalities [1]. As analgesics are a frequent means of suicide [2], we could assume that it is related to their accessibility. One could also hypothesize that suicidal vulnerability might be associated with an over-sensitivity to pain reflected by a propensity to analgesic use [3]. But are analgesics more prescribed to patients carrying a suicidal vulnerability? Our study aims to examine the association between suicidal vulnerability and analgesic consumption in a population-based study. We hypothesized that people with a past history of suicide attempts (i.e. carrying suicidal vulnerability) will be more prone to consuming analgesics than subjects without such a history. We selected subjects among a cohort recruited in community-dwelling people over 65 years of age between 1999 and 2001 (ESPRIT project described in [4]). The ESPRIT project aims to construct a comprehensive database incorporating clinical, biological, genetic and environmental risk factors of psychiatric diseases; it was not specifically designed for our study but it permits through the wealth of the data to meet our issue.We included 960 individuals for whom the exhaustive list of medical prescriptions was available from the health insurance databases (2001-2003). We excluded subjects suffering from dementia (n = 21), those who died before 2003 (n = 27) and subjects taking psychotropic drugs without reporting psychiatric disorder (n = 55). The sample was divided into three groups: (1) suicide attempters (SA, n = 41) having a lifetime history of suicide attempt, (2) affective controls (AC, n = 410) having a history of major depression (DSM-IV criteria) or current high depressive symptoms (CES-D score >16 [5]) without history of suicide attempt and (3) healthy controls (HC, n = 406) having no psychiatric history and current low depressive symptoms. A standardized interview assessed demographic characteristics, general health, medical history, hospitalization, self-reported social isolation and current alcohol and tobacco consumption. Chronic illnesses included cardiac ischemic disease, diabetes, hypertension, asthma, thyroid pathology and cancer. Prescriptions for analgesics were classified according to the WHO analgesic ladder [6]. We considered two grades of medication: grade I for non-opioid drugs (step 1 for low-to-moderate pain) and grade II for opioid drugs (steps 2 and 3 for severe pain). The use of non-prescribed drugs was also recorded. Descriptive analyses were carried out using the χ2 or Kruskal-Wallis tests, based on the variable characteristics (see online suppl. material at www.karger.com/doi/10.1159/000350504 for more information). Binary and multinomial logistic regression models were conducted to evaluate the association between drug groups (SA, AC and HC) and analgesic consumption over a 3-year follow-up period. Covariates were gender, age, education, living alone, chronic disease, headaches, hospitalization and subjective health. Analyses were performed with SAS software (version 9.2, SAS Statistical Institute, Cary, N.C., USA).The mean age of the sample was 74.3 years (SD = 4.9). The percentage of women was higher in SA compared to HC (82.9 vs. 49.8%, p < 0.001) but not compared to AC (70.5%, p = 0.09). SA lived more often alone compared to HC (51.2 vs. 18.5%, p < 0.001) but not compared to AC (39.3%, p = 0.1). Current high depressive symptoms were more frequent in AC than SA (78.3 vs. 63.4%, p = 0.03; see online suppl. material). There were no between-group differences for comorbid chronic diseases, subjective health and frequency of consultation or hospitalization. During the 3-year follow-up, the proportion of subjects taking analgesics was 92.7% in the SA group, 90.5% in the AC group and 84.5% in the HC group. Patients using opioid analgesics (even once) were assigned to the group of grade II users. Exclusive grade I users were 36.6% in the SA group, 46.1% in the AC group and 52.2% in the HC group. Grade II users were 56.1% in the SA group, 44.4% in the AC group and 32.3% in the HC group. Compared to grade I use, repartition of grade II consumption was inversely distributed between the three groups, with significant differences between HC and SA (not shown). Logistic regression was used to assess whether the three groups were significantly different with regard to global analgesic use after adjustment for gender, age, education, chronic disease, hospitalization, living alone and subjective health. There were no significant differences between the three groups for global analgesic consumption (p = 0.41, model 1). Multinomial logistic regression showed no significant between-group differences for grade I or II use compared to no use (models 2A and 2B). When comparing grade I to grade II consumption, AC and SA were more prone to taking grade II analgesics than HC [OR = 1.37 (95% CI: 1.01-1.91) and OR = 2.33 (95% CI: 1.15-4.73), respectively] with no difference between AC and SA (model 2C). Table 1 shows detailed comparison of different analgesic consumption in the three groups.After excluding cancer cases to eliminate an impact on strong opioid prescriptions [7], SA were more prone to taking grade II drugs than HC (OR = 2.35, 95% CI: 1.15-4.89) compared to grade I consumption (model C; table 1). Logistic regression also showed a significant overall effect of gender and education level (p < 0.01) on analgesic consumption. No significant effect of age (p = 0.17), chronic disease (p = 0.43), headaches (p = 0.23), hospitalization (p = 0.18), subjective health (p = 0.91) and living alone (p = 0.47) on drug taking was observed (data not shown).To summarize, only opioid consumption was significantly increased in subjects having a history of depression, with the highest risk of opioid consumption in former SA. It was not related due to differences in health status or care accessibility. As depression in the elderly is commonly associated with painful symptoms [8], AC should have been prone to taking analgesics if their consumption only depended on their depressive state. Moreover, there were no between-group differences in antidepressant consumption, which modulates both depression and pain [9]. As a whole, it may suggest the involvement of a modified pain perception in suicidal vulnerability, possibly linked to the opioid system. The strengths of this study are the inclusion of community-dwelling people and the assessment of exhaustive prescriptions during the follow-up. Limitations are due to lack of information in the ESPRIT study. Criteria based on dose, treatment duration and reason for prescribing could not be considered. Moreover, musculoskeletal symptoms, common in elderly persons, were not recorded.Thus, we cannot exclude that opioid prescriptions depend on severe pain related to chronic illnesses not considered here. However, there are no findings indicating a higher prevalence of musculoskeletal disorders among subjects with suicidal vulnerability. Self-medication may lead to underestimating the consumption of analgesics, but analgesic self-medication was recorded at baseline and during the follow-up and is not influenced by depression in chronic pain [10]. Further studies including criteria on dose and treatment duration are needed to strengthen these findings.The increased consumption ofopioid analgesics in patients carrying a suicidal vulnerability suggests the interest to investigate the existence of an increased sensitivity to pain and its biological mechanisms in suicidal behaviour.The ESPRIT Project is financed by the regional government of Languedoc-Roussillon, the Agence Nationale de la Recherche (ANR) and an unconditional grant from Novartis. The authors thank Valerie Macioce for her careful reading of the manuscript. All authors declare no conflicts of interest related to the manuscript.