OBJECTIVES: This study examined concurrent associations and predictors at first indication of nonadherence to antipsychotic medication four years after a first episode of psychosis.

METHODS: A prospective cohort of 171 patients in urban Ireland with a first episode of psychosis was followed up four years after inception (follow-up primary analysis, N=84; secondary analysis, N=104).

RESULTS: At the four-year follow-up 76% were adherent and 24% were not. Nonadherence was concurrently associated with substance misuse (p<.01), increased symptomatology (p<.01), less insight (p=.01), lower global functioning (p<.01), and negative attitudes toward medication (p<.01). Compared with other patients, those who were nonadherent had more readmissions (p=.01). Predictors of future nonadherence were substance misuse (p=.02) and duration of untreated psychosis (p=.04).

CONCLUSIONS: This prospective investigation confirms previous cross-sectional studies. The association between longer duration of untreated psychosis and nonadherence warrants further research because it could be interpreted as further evidence of the importance of early intervention.