Distinct Polygenic Score Profiles in Schizophrenia Subgroups With Different Trajectories of Cognitive Development.

OBJECTIVE: Different cognitive development histories in schizophrenia may reflect variation across dimensions of genetic influence. The authors derived and characterized cognitive development trajectory subgroups within a schizophrenia sample and profiled the subgroups across polygenic scores (PGSs) for schizophrenia, cognition, educational attainment, and attention deficit hyperactivity disorder (ADHD). METHODS: Demographic, clinical, and genetic data were collected at the National Institute of Mental Health from 540 schizophrenia patients, 247 unaffected siblings, and 844 control subjects. Cognitive trajectory subgroups were derived through cluster analysis using estimates of premorbid and current IQ. PGSs were generated using standard methods. Associations were tested using general linear models and logistic regression. RESULTS: Cluster analyses identified three cognitive trajectory subgroups in the schizophrenia group: preadolescent cognitive impairment (19%), adolescent disruption of cognitive development (44%), and cognitively stable adolescent development (37%). Together, the four PGSs significantly predicted 7.9% of the variance in subgroup membership. Subgroup characteristics converged with genetic patterns. Cognitively stable individuals had the best adult clinical outcomes and differed from control subjects only in schizophrenia PGSs. Those with adolescent disruption of cognitive development showed the most severe symptoms after diagnosis and were cognitively impaired. This subgroup had the highest schizophrenia PGSs and had disadvantageous cognitive PGSs relative to control subjects and cognitively stable individuals. Individuals showing preadolescent impairment in cognitive and academic performance and poor adult outcome exhibited a generalized PGS disadvantage relative to control subjects and were the only subgroup to differ significantly in education and ADHD PGSs. CONCLUSIONS: Subgroups derived from patterns of premorbid and current IQ showed different premorbid and clinical characteristics, which converged with broad genetic profiles. Simultaneous analysis of multiple PGSs may contribute to useful clinical stratification in schizophrenia.

Verbal Learning and Memory Enhancement Strategies in Schizophrenia: A Randomized, Controlled Investigation.

OBJECTIVES: Verbal episodic memory is a key domain of impairment in people with schizophrenia with close ties to a variety of aspects of functioning and therapeutic treatment response. A randomized, blinded trial of two mnemonic strategies for verbal episodic memory deficits for people with schizophrenia was conducted. METHODS: Sixty-one people with schizophrenia were assigned to one of three experimental conditions: training in a mnemonic strategy that included both visualization and narrative structure (Story Method), a condition in which participants were trained to visualize words interacting with one another (Imagery), or a non-trained control condition in which participants received equivalent exposure to training word lists and other verbal memory assessments administered in the other two conditions, but without provision of any compensatory mnemonic strategy. Participants were assessed on improvements in recall of the word list used as part of training, as well as two, standardized verbal memory assessments which included stimuli not used as part of strategy training. RESULTS: The Story Method produced improvements on a trained word list that generalized to a non-trained, prose memory task at a 1-week follow-up. In contrast, provision of a mnemonic strategy of simple visualization of words produced little improvement on word recall of trained words or on measures of generalization relative to the performance of participants in the control condition. CONCLUSIONS: These findings support the inclusion of enriched mnemonic strategies consisting of both visualization and narrative structure in sustained and comprehensive programs of CR for enhancement of verbal episodic memory in schizophrenia. (JINS, 2017, 23, 352-357).