Dissociable impairments of verbal learning differentiate childhood risk profiles for schizophrenia

Abstract

Poor verbal learning and memory function is well-documented among individuals with schizophrenia and those at clinical high-risk for psychosis. This study aimed to identify these impairments among children aged 9–12 years with different schizophrenia risk profiles (family history or antecedents of schizophrenia, each of higher^[H] or lower^[L] risk load) relative to typically developing peers. These three groups were recruited via community-screening, and differentiated for analysis into: typically developing children (TD = 45); children who had 1 first- or ≥2 second-degree affected relatives (FHx^H = 16) or one second-degree relative (FHx^L = 15); and children presenting multiple replicated antecedents of schizophrenia whose clinical symptoms persisted at 2- and/or 4-year follow-up (ASz^H = 16) or remitted during follow-up (ASz^L = 16). Verbal learning/memory measures assessed at baseline (age 9–12 years) included: (i) total recall; (ii) trial 1 recall; (iii) learning score; (iv) intrusions; (v) total words lost; and (vi) serial position patterns. Analyses of variance indicated that FHx^H and ASz^H youth demonstrated impaired total recall compared to TD and ASz^L children and lost significantly more words between trials than TD and FHx^L children. Learning score was impaired among both FHx^H and FHx^L relative to TD and ASz^L children. Thus, among putatively at-risk children, total words recalled and lost distinguished those with higher risk load (by family history or persistent antecedent symptomology), whereas learning score indexed familial vulnerability. Follow-up of the sample is needed to determine the capacity of verbal learning deficits to predict later illness and provide a potential avenue for early remediation to improve clinical or functional outcomes.