The relationship between duration of untreated psychosis (DUP) and executive function (EF) in patients with first-episode psychosis (FEP) is controversial. We aim to assess the influence of DUP on changes in EF over a 2-year period in subjects with early-onset FEP (first psychotic symptom before age 18) and less than 6 months of positive symptoms.

A total of 66 subjects were included in the study (19 females [28.8%], mean age 16.2 ± 1.6 years). The influence of DUP on changes in EF over the 2-year follow-up (expressed as a composite score of 5 cognitive abilities: attention, working memory, cognitive flexibility, response inhibition, and problem solving) was estimated using a multivariate linear regression model after removing the effect of intelligence quotient and controlling for age, gender, diagnosis, premorbid adjustment, severity of positive and negative symptoms at baseline, global functioning at baseline, and mean daily antipsychotic dosage during follow-up.

Mean DUP was 65.0 ± 6.9 days (95% confidence interval [CI], 51.2, 78.8). Median DUP was 47.5 days (range 2–180 days). Negative symptoms at baseline was the only variable significantly associated with EF at baseline (10.9% of explained variance [e.v. 10.9%], p = 0.007). Only shorter DUP (e.v. 8.7%, p = 0.013) and greater severity of baseline negative symptoms (e.v. 10.0%, p = 0.008) were significantly associated with greater improvement in EF.

In early-onset FEP, shorter DUP was associated with greater improvement in EF over a 2-year follow-up period.