The present study demonstrates marked differences between socio-occupational groups in frequent use of psychotropic drugs (for fatigue, nervousness, anxiety, or insomnia) among young adults aged 18–29. Use was strongly mediated among manual workers, and slightly mediated among the other socio-occupational groups, by not-good health status, musculoskeletal disorders/other diseases, lack of family support, and certain personality traits such as being worried, nervous or sad. Current smoking, and visual and cognitive disabilities had significant crude odds ratios but they became non-significant when controlling for all factors considered. This could be explained by the interdependence of factors.
This study reports that frequent psychotropic drug use was common among young adults. Comparison with other investigations is difficult because of variations in the populations studied, the psychotropic drugs considered, and the methodological approaches used. In addition, few researchers have focused on young adults. In France, 9.3%, 16.1% and 5.9% of adults (aged 18–75) used antidepressants, sleeping pills, and drugs to improve their physical/intellectual performance . One-third of French workers used drugs for work-related reasons, 20% to feel better, 12% to control an awkward symptom, and 18% to relax after a difficult day's work . The ESEMeD study focused on the use of antidepressant, anxiolytic, and antipsychotic or mood-stabilizing drugs in adults (aged 18+) . It reported a prevalence of 19.2% in France, 15.5% in Spain, 13.7% in Italy, 13.2% in Belgium, 7.4% in the Netherlands, and 5.9% in Germany. Bruffaerts et al.  reported that about 19% of Belgian people aged over 18 use a psychotropic drug.
Our results confirm the well-known sex ratio [1, 26, 28]. Women and female adolescents are more likely than their male counterparts to have any mental disorder and to take psychotropic drugs [1, 2, 26], to be given such drugs following a medical consultation, to receive longer courses, and to renew the treatment . It should be noted that we found a crude odds ratio of 2.08 and an adjusted odds ratio of 1.60 when controlling for socio-occupational category and other confounders, whereas the ESEMeD study (conducted in six European countries) reported an adjusted odds ratio of 2.1 (95% CI 1.9–2.4) when controlling for age, marital status, educational level, employment, disability, illness leave, urban/rural location, and country . This suggests that the sex ratio was only partly explained by these risk factors or confounders. Sex difference may in part be attributable to a higher incidence of depressive symptoms among females, and their greater willingness to seek medical help .
The present study reveals that housewives and students are at high risk for psychotropic drug use, whereas unemployed young adults are not. Overall, housewives had less good health status than female workers did, although this pattern was more consistent for women of low educational level . University students report higher levels of anxiety and depressive symptoms than are seen in general population norms . Several stressors, such as financial problems, and academic pressures and their consequences on social life, have an adverse effect on the mental health of students .
An important finding of our study is that there are marked disparities in psychotropic drug use among young adults from different socio-occupational groups. Manual workers, employees, farmers, craftsmen, and tradesmen were at high risk compared with upper/intermediate professionals. This was expected as work conditions, diseases, occupational injuries, impairments, disabilities, and health-related behaviours also differ greatly [6, 15, 18, 23, 37, 46] and may increase psychotropic drug use [1, 15, 37]. Similar differences were observed between socio-occupational groups in impairments among subjects aged less than 40 years . Health hazards at work are still a major determinant of poor health . In the European Union, 3.6% of the total burden of disease is directly related to work environments . In France, the disparities between social groups in morbidity, mortality and premature mortality are higher than in the other western European countries . Poor working conditions, and particularly cumulative job stress, lead to physical and mental disturbances, and consequently to psychotropic drug use . As noted above, one in every three French workers uses medications or other legal psychoactive substances in order to cope with work-related difficulties, and such use is more common in employees and manual workers . Fatigue is related to the physical demands of job. The volume of services provided and job dissatisfaction are associated with hypnotic and tranquillizer use . Work-related fatigue is generated by repeated episodes of adverse work experience and leads to the development of stress reactions, psychological overload, and health problems . Unemployed people here had a crude odds ratio of 1.94, but it was not significant. However, that may relate to a lack of statistical power, suggesting that a study with a larger sample is needed.
As reported by other authors [10, 11], we found that not-good heath status and diseases were common in young adults, and that they were strongly associated with psychotropic drug intake. Musculoskeletal disorders were most common and had a marked effect on psychotropic medication. The high risk among subjects with not-good health status or musculoskeletal disorders is of paramount importance as their prevalence is high in the population of all ages [6, 46]. Our results are consistent with those of other studies that have shown that psychotropic medication is associated with sick leave due to illness, severe physical symptoms, and disability [1, 48]. Not-good health status, disease, and psychological distress are strongly related to onset of fatigue and sleep problems [25, 49]. The presence of disease is, along with sensory or cognitive disabilities, a long-term risk factor for injuries and falls [6, 23].
Our investigation shows that self-reported personality traits were related to psychotropic drug use, and that the simple items used were pertinent. Subjects who described themselves as nervous, not calm, worried, aggressive or sad were at increased risk. It may be that these self-reported personality traits may be interpreted as a sort of a justification for the use/abuse of psychotropic medications This finding was expected because self-reported personality traits are associated with smoking, alcohol consumption, illicit drug use, and occupational injury [38, 39].
We found that lack of family support was strongly associated with psychotropic medication among young adults. The role of the family in substance use is well documented, but not among this age group . We also demonstrated that visual and cognitive disabilities were associated with psychotropic drug use in univariate analysis but not in multivariate analysis taking into account sex, socio-occupational category, health status, disease, family support, and personality traits. These results suggest that the increased risks associated with visual and cognitive disabilities could be attributed to those confounders, indicating that preventive measures to reduce psychotropic medication use among young adults may need to be focused on health status, diseases, family support, and personality traits rather than low education level, disability, and low income which are mainly related to socio-economic groups. The ESEMeD study found that psychotropic drug use was related to lower levels of education, but health status, disease, family support, and socio-occupational category were not considered . A low education level is well known to be associated with disability , membership of a lower social class, and with adverse work conditions, lifestyle and living conditions.
Our study failed to detect an association between frequent psychotropic drug use and overweight, underweight, or alcohol abuse. McElroy et al.  stated that obesity is associated with depressive disorders, but most overweight and obese people in the community do not have mood disorders. Bültmann et al.  also found an increased risk of fatigue in underweight women. Eating alone, social isolation, and stressors are the main reasons for low weight reported by the subjects concerned, mainly due to poor nutritional status . The present study found a significant relationship between smoking and psychotropic drug use in univariate analysis and a relationship close to significance in multivariate analysis taking into account all covariables. Smoking is associated with low socio-economic group, low educational level, low income, living alone, occupational and domestic injuries, and premature death (≤ 70 yr) [8, 40, 52]. Preventive measures to reduce psychotropic medication may consequently need to be focused on smokers. Alcohol abuse affected 7.7% of young adults; it had a crude odds ratio of 1.46 (slightly lower than that for smoking (1.52)) that was non-significant, again perhaps because of a lack of statistical power, suggesting that a study with a larger sample is needed.
Our study demonstrates that disparities in frequent use of psychotropic drugs were mediated by not-good health status, musculoskeletal disorders, lack of family support, and certain personality traits, all of which are generally chronic or long-lasting conditions, particularly among lower socio-economic groups. Therefore, psychotropic drug use generated by them would also last for a long time. Consequently, general practitioners may need to monitor those of their patients most at risk. According to the ESEMeD study, a significant proportion of individuals, both with and without mental disorders, are inappropriately treated . These results confirm the roles of material conditions and psychological factors in social inequalities in health [15, 17, 30, 31, 37, 53] but they also point out a relatively important role of personality in psychotropic medication. These findings may help us understand socio-occupational inequalities in health, which, it should be noted, are currently an area of considerable interest and a preoccupation among policy officials in most European countries and elsewhere [17, 30, 31].
Any selection bias here would be small: 96% of households had telephones at the time of the study, and only 16% had confidential addresses. Discussions before the survey, for example with associations of people with disability, suggested that neither is likely to be related to health status or living conditions. The age and sex distributions of the sample reflect those of the general population of Lorraine . The percentage of manual workers (18%) was similar to that of the Lorraine population (21%) . Note also that the incidence rate of occupational injury and the prevalence of various types of diseases and disabilities, for example, are similar to those of the general population [6, 8, 14, 55]. The quality of the completed questionnaires was very good. All the factors studied had been validated and used in other investigations [6, 15, 26, 37–39].
The present study had some limitations. First, the psychotropic drugs considered included those for fatigue, nervousness, anxiety, and/or insomnia. Fatigue is associated with psychological distress and absence due to sickness [16, 56], and sleep problems are related to depression, pain, and hypnotic-sedative use . Second, the participation rate was modest although it was similar to that achieved in similar surveys in France [1, 57]. Third, as the study used a self-administered questionnaire, the results should be interpreted with caution, particularly given a possible selection bias. However, the self-administered occupational health history questionnaire is reliable and valid . The non-response bias in mailed health surveys is small . In population-based studies, self-assessment of vision is similar between participants and non-participants , and self-assessment of memory is generally valid .