Due to the paucity of previous studies, we wanted to elucidate the pharmacoepidemiology of antipsychotics in schizophrenia in a general population sample, and the association between long-term antipsychotic use and outcomes.

The sample included 53 schizophrenia subjects from the Northern Finland Birth Cohort 1966 with at least ten years of follow-up (mean 18.6 years since illness onset). Data on lifetime medication and outcomes (remission, Clinical Global Impression [CGI], Social and Occupational Functioning Assessment Scale [SOFAS]) were collected from medical records, interviews, and national registers.

During the first two years 22 (42%), between two to five years 17 (32%), and between five to ten years 14 (26%) subjects had used antipsychotics less than half of the time. Drug-free periods became rarer during the follow-up. The mean lifetime daily dose of antipsychotics was 319mg in chlorpromazine equivalents. A high lifetime average and cumulative dose and antipsychotic polypharmacy were associated with a poorer outcome in all measures, whereas having no drug-free periods was associated with a better SOFAS score and a low proportion of time on antipsychotics with a better CGI score.

In our population-based sample, the use of antipsychotics increased during the first five years of illness and was relatively stable after that. Our results suggest that both low dose and proportion of use, and having no drug-free periods, are associated with better outcomes, which concords with current treatment recommendations and algorithms. High long-term doses and polypharmacy may relate to poor outcomes.