Association between platelet MAO activity and lifetime drug use in a longitudinal birth cohort study.

RATIONALE: Platelet monoamine oxidase (MAO) activity, a marker of central serotonergic capacity, has been associated with a variety of problem behaviours. However, studies on platelet MAO activity and addictive drugs have not consistently linked MAO activity with addiction or reported to predict illicit substance use initiation or frequency. OBJECTIVES: Platelet MAO activity and illicit drug use was examined in a longitudinal birth cohort study. METHODS: The sample included both birth cohorts (original n = 1238) of the Estonian Children Personality Behaviour and Health Study. Longitudinal association from age 15 to 25 years between platelet MAO activity and lifetime drug use was analysed by mixed-effects regression models. Differences at ages 15, 18 and 25 were analysed by t-test. Cox proportional hazard regression analysis was used to assess the association between platelet MAO activity and the age of drug use initiation. RESULTS: Male subjects who reported at least one drug use event had lower platelet MAO activity compared to nonusers, both in cross-sectional and longitudinal analyses. Males with low platelet MAO activity had started to use drugs at a younger age. Moreover, in male subjects who had experimented with illicit drugs only once in lifetime, low platelet MAO activity was also associated with higher risk at a younger age. In females, platelet MAO activity was not associated with drug use. CONCLUSION: In males, low platelet MAO activity is associated with drug abuse primarily owing to risk-taking at early age.

Suicide among older people in relation to their subjective and objective well-being in different European regions.

The aim of this study was to establish how different types of welfare states shape the context of the everyday life of older people by influencing their subjective well-being, which in turn might manifest itself in suicide rates. Twenty-two European countries studied were divided into Continental, Nordic, Island, Southern, and post-socialist countries, which were subdivided into Baltic, Slavic, and Central-Eastern groups based on their socio-political and welfare organization. Suicide rates, subjective well-being data, and objective well-being data were used as parameters of different welfare states and obtained from the World Health Organization European Mortality Database, European Social Survey, and Eurostat Database. This study revealed that the suicide rates of older people were the highest in the Baltic countries, while in the Island group, the suicide rate was the lowest. The suicide rate ratios between the age groups 65+ and 0-64 were above 1 (from 1.2 to 2.5), except for the group of the Island countries with a suicide rate ratio of 0.8. Among subjective well-being indicators, relatively high levels of life satisfaction and happiness were revealed in Continental, Nordic, and Island countries. Objective well-being indicators like old age pension, expenditure on old age, and social protection benefits in GDP were the highest in the Continental countries. The expected inverse relationship between subjective well-being indicators and suicide rates among older people was found across the 22 countries. We conclude that welfare states shape the context and exert influence on subjective well-being, and thus may lead to variations in risk of suicide at the individual level.