Attention-deficit/hyperactivity disorder in youth with psychosis spectrum symptoms

Childhood attention deficit-hyperactivity disorder (ADHD) is common in psychotic disorders. However, prevalence estimates vary widely and the impact of ADHD on the severity of psychotic symptoms and associated features is unclear. We used the Philadelphia Neurodevelopmental Cohort (PNC; n = 9498 youth age 8-21), which includes a comprehensive structured interview of clinical symptoms and the Penn Computerized Neurocognitive Battery (CNB), to clarify the prevalence of ADHD in psychosis spectrum (PS) youth and determine if comorbid ADHD is associated with severity of psychotic symptoms and cognitive impairment.

Prevalence of ADHD among PS youth was established by comparing PS youth to all other youth in the PNC cohort. Cognition was compared between four groups: typically developing (TD), ADHD, PS without ADHD (PS-ADHD), and PS with ADHD (PS+ADHD). To evaluate the impact of ADHD on psychosis symptomatology, severity of positive and negative psychotic symptoms was compared between PS-ADHD and PS+ADHD groups.

ADHD was more prevalent in PS youth compared to non-PS youth (45% vs. 20%). Cognition was significantly impaired in PS youth compared to TD youth, but the presence of ADHD in PS youth was not associated with greater cognitive impairment. Co-morbid ADHD was, however, associated with more severe psychosis symptoms in PS youth.

ADHD is more common among PS youth compared to youth without PS symptoms and is associated with more severe psychotic symptoms, but not severity of cognitive impairment. The association between ADHD and psychotic disorders may be mediated by psychosis symptoms in youth and may manifest a more stable cognitive impairment.