In first-episode schizophrenia, longer duration of untreated psychosis (DUP) predicts poorer outcomes.

To address whether the relationship between DUP and outcome is a direct causal one or the result of association between symptoms and/or cognitive functioning and social functioning at the same time point.

Symptoms, social function and cognitive function were assessed in 98 patients with first-episode schizphrenia at presentation and 1 year later.

There was no significant clinical difference between participants with short and long DUP at presentation. Linear regression analyses revealed that longer DUP significantly predicted more severe positive and negative symptoms and poorer social function at 1 year, independent of scores at presentation. Path analyses revealed independent direct relationships between DUP and social function, core negative symptoms and positive symptoms. There was no significant association between DUP and cognition.

Longer DUP predicts poor social function independently of symptoms. The findings underline the importance of taking account of the phenomenological overlap between measures of negative symptoms and social function when investigating the effects of DUP.