Cognitive deficits in early-onset psychosis appeared larger in older patients

Design

Cross-sectional cohort (EPIMex)

Population

1004 young people with early-onset psychosis, 146 siblings, 1077 psychiatric controls, Mexico

Primary outcome

Seven cognitive functions and general cognitive ability (g)

Effect

Non-affective psychosis impaired on all measures (β 0.27–0.51); affective on most (β 0.13–0.25); siblings not impaired overall

The Early Psychosis Investigation in Mexico study tested seven cognitive functions in 1004 children and adolescents with early-onset psychosis, 146 of their siblings, and 1077 psychiatric controls without psychosis. Patients were split into affective psychosis (schizoaffective, psychotic depression or bipolar disorder; 695) and non-affective psychosis (schizophrenia and others; 309).

Non-affective patients were impaired on every measure (standardised β 0.27 to 0.51); affective patients on most, more mildly (0.13 to 0.25). Siblings as a group were not impaired. The gap grew with age: in non-affective psychosis it was small in children, medium in adolescents and large in young adults; in affective psychosis children showed none and adults a large gap; siblings showed a gap only in adulthood. Working memory, verbal memory, verbal fluency and processing speed carried the age-related differences.

The practical point is that cognition in a young person with psychosis is not a fixed baseline. It deserves assessment and re-assessment, and school and vocational plans should allow for it. Because this is a single cross-sectional sample, it cannot show that cognition declines within the same person over time.

• Assess cognition — working memory, verbal memory, processing speed — in young people with psychosis, not only positive symptoms.
• Repeat the assessment as they move from school to college or work, when demands on these functions rise.
• With the young person's (and guardian's) consent, explain to family and school that difficulty with memory and concentration is part of the illness, not lack of effort.
• Ask about academic decline in siblings too; a gap in adulthood was seen even without psychosis.
• Refer for cognitive remediation or educational support where it is available.

Why it matters

It suggests the cognitive gap in early-onset psychosis widens through adolescence — the window when education and work are decided.

Don't overread it

This was cross-sectional: it compares different people at different ages and cannot show decline within an individual.

The statistics, in plain English

A standardised β of 0.27 to 0.51 means patients scored roughly a quarter to a half of a standard deviation below controls — noticeable in daily functioning at the upper end. The 'age-associated deviation' is a larger gap in older participants than in younger ones in the same sample, not a measured change over time.

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