Early versus adult onset of schizophrenia: an examination of premorbid and current IQ.

ABSTRACT:

Background

Cognitive deficits are core findings in schizophrenia, but whether the severity of impairments is related to the age of onset remains unclear. We hypothesized that early onset schizophrenia (EOS; onset before age 19) is associated with lower IQ compared to adult-onset schizophrenia (AOS; onset from age 19).

Methods

We included 99 adult patients with EOS (age of onset: 15.3 ± 2.8 years), 282 adult patients with AOS (age of onset: 26.5 ± 7.4 years), and 863 adult healthy controls (HC). We assessed current IQ with Wechsler Abbreviated Scale of Intelligence (WASI) and estimated premorbid IQ with National Adult Reading Test (NART).

Results

Both patient groups had lower current IQ than HC (p < 0.001). Full-scale (p = 0.004), performance (p = 

SUBMITTER: Calkova T 

PROVIDER: S-EPMC12549396 | biostudies-literature | 2026 Mar

REPOSITORIES: biostudies-literature