Background. Higher incidence of psychotic disorders and underuse of mental health services
have been reported among many migrant populations. This study examines the initiation and
continuity of antipsychotic treatment among migrants and non-migrants with a non-affective
psychosis during a new treatment episode.

Methods. This study is based on a nationwide sample of migrants and Finnish-born controls.
Participants who were diagnosed with a psychotic disorder in 2011–2014 were identified from
the Care Register for Health Care (n = 1693). Information on purchases of antipsychotic drugs
in 2011–2015 was collected from the National Prescription Register. The duration of antipsychotic
treatment since diagnosis was estimated using the PRE2DUP model. Cox regression
analysis was used to study factors that are associated with discontinuing the use of medication.

Results. There were fewer initiators of antipsychotic treatment after being diagnosed with
psychosis among migrants (68.1%) than among Finnish-born patients (73.6%). After controlling
for sociodemographic background and factors related to the type of disorder and treatment,
migrants were more likely to discontinue medication (adjusted hazard ratio 1.28,
95% confidence interval 1.08–1.52). The risk of discontinuation was highest among migrants
from North Africa and the Middle East and Sub-Saharan Africa and among recent migrants.
Non-use of antipsychotic treatment before being diagnosed with psychosis, involuntary hospitalization
and diagnosis other than schizophrenia were associated with earlier discontinuation
both among migrants and non-migrants.

Conclusions. Migrants with a psychotic disorder are less likely to continue antipsychotic
treatment than non-migrants. The needs of migrant patients have to be addressed to improve
adherence.