BACKGROUND: Long duration of untreated psychosis (DUP) has been linked with more severe psychotic and negative symptoms. However, it is uncertain which specific psychotic and negative domains that are affected over time and if these are stable over the course of illness.

OBJECTIVE: To examine whether DUP is associated with psychotic and negative symptoms measured longitudinally up to 10 years after initial assessment.

METHOD: Psychopathology of participants from the OPUS I trial, aged 18-45 years with a baseline ICD-10 schizophrenia spectrum diagnosis, excluding schizotypal disorder (468 participants left), was assessed at baseline and 2, 5 and 10 years after initial assessment. The associations between DUP and domains of positive and negative symptoms were calculated using linear regression analysis.

RESULTS: Longer DUP was significantly associated with the severity of hallucinations, delusions and anhedonia-asociality at baseline. Longer DUP remained significantly associated with hallucinations, delusions and anhedonia-asociality after 2 years. DUP was significantly associated with hallucinations, delusions, avolition-apathy and anhedonia-asociality after 5 years. Longer DUP was still significantly associated with hallucinations and delusions but not with any of the negative symptom subdomains after 10 years. Results were not substantially changed after adjusting for treatment with antipsychotic medication at each point in time.

CONCLUSION: We demonstrated associations between DUP and the severity of hallucinations and delusions which persist after at least 10 years of follow-up and an association between longer DUP and anhedonia-asociality which persist until 5 years of follow-up. Further, DUP was associated with avolition-apathy after 5 years.