Psychotropic drug and polypharmacy use among adolescents and young adults: findings from the Finnish 1981 Nationwide Birth Cohort Study.

BACKGROUND: Little is known about the timing of the start of psychotropic drug use and psychotropic polypharmacy use. AIMS: This study describes these patterns in a Finnish representative cohort aged between 12 and 25.
METHODS: 5525 subjects born in 1981 were followed up between 1994 and 2005 using the Finnish National Prescription Register.
RESULTS: Survival analysis revealed that the cumulative incidence of any psychotropic drug use was 1.3% by age 15, 6.1% by age 20 and 15.2% by age 25. Antidepressants and benzodiazepines were the most used drug groups, with cumulative incidences of 12.2% and 5.2%, respectively, by age 25. The cumulative incidence of polypharmacy was 0.02% by age 15, 0.9% by age 20 and 4.1% by age 25, i.e. having purchased at least two psychotropic drugs from different classes during the same day. Polypharmacy occurred among the majority of antipsychotic and benzodiazepine users, but among a minority of antidepressant users. More females than males had used any psychotropic drug, antidepressants, the antidepressant-benzodiazepine combination and the antidepressant-mood stabilizer combination.
CONCLUSIONS: Both general psychotropic drug use and psychotropic polypharmacy use was often started in late adolescence.