Psychosis-risk studies have examined help-seeking adolescents and young adults. Population-based studies evaluating psychotic symptoms and neurocognitive performance across childhood are needed for “growth charting” cognitive development. We hypothesized that psychosis spectrum youths have delayed neurocognitive age relative to chronological age. We expected larger lags with increased symptom severity and in late adolescence and early adulthood.
To examine neurocognitive age and compare typically developing participants with psychosis spectrum participants.
Design, Setting, and Participants
The Philadelphia Neurodevelopmental Cohort is a genotyped sample, with electronic medical records, enrolled in the study of brain behavior. In an academic and children’s hospital health care network, a structured psychiatric evaluation was performed and a computerized neurocognitive battery administered to evaluate performance in several domains. From 18 344 youths in the recruitment pool who were aged 8 to 21 years, physically and cognitively capable of participating, and proficient in English, participants were randomly selected with stratification for age, sex, and ethnicity. A total of 9138 participants were enrolled in the study between November 1, 2009, and November 30, 2011, and 2321 endorsed psychotic symptoms: 1423 significant (psychosis spectrum) and 898 limited (psychosis limited). They had no comorbid medical conditions. They were compared with 981 participants endorsing significant other psychiatric symptoms and with 1963 typically developing children with no psychiatric or medical disorders.
Main Outcomes and Measures
The computerized neurocognitive battery provides accuracy and speed measures on 12 tests and speed measures alone on 2, yielding 26 measures used in a regression analysis to predict chronological age. Prediction was performed on the entire set and separately for each domain (executive, episodic memory, complex cognition, social cognition, and sensorimotor speed).
Throughout childhood and adolescence, the psychosis spectrum group had lower predicted age compared with the typically developing group and the group with other psychiatric symptoms. The psychosis spectrum group had a greater developmental lag than the psychosis limited group. The lags were most pronounced for complex cognition and social cognition and were smallest for sensorimotor speed.
Conclusions and Relevance
Individuals who endorse psychotic symptoms are neurocognitively delayed across the age range; this delay relates to symptom severity and is not prominent in other psychiatric disorders. Combined clinical and neurocognitive assessment can facilitate early detection and targeted intervention to delay or ameliorate disease progression.