Cognitive remediation for individuals with psychosis: Efficacy and mechanisms of treatment effects

The popularity of cognitive remediation (CR) interventions for individuals
with psychosis is in part based on the well-established link between cognition and
functioning and the assumption that by targeting cognition, function can improve. While
numerous trials have reported CR's efficacy, it is still not considered an evidencebased
treatment. Importantly, little is known about the mechanisms through which it
may affect functioning. Method: In this study, we evaluated CR's proximal and distal
effects, and examined potential mechanisms. Seventy-five individuals with psychotic
disorders were randomized to a combination of strategy-based and drill and practice
cognitive remediation (CR) or Wait-List Control (WLC), with assessments of training
task performance, neurocognition, functional capacity, symptoms and functioning
conducted at baseline, end of the 2-month intervention, and 2-month follow-up (FU).
Results: Compared to TAU, CR was associated with large post-training improvements
on training tasks targeting attention, visuospatial memory, and verbal learning and
memory, with persisting group differences at 2-month follow-up. These generalized to
mostly large improvements on neuropsychological measures targeting visuospatial
memory, verbal learning and memory, delayed verbal memory, and verbal working
memory. While there were no CR-associated improvements on measures of functional
capacity, symptoms, or a self-report measure of independent living skills, there was an
effect on an interviewer-rated measure of functioning (QLS), which appeared primarily
driven by the Intrapsychic Foundations subscale. Finally, for those randomized to CR,
there were significant, medium-sized correlations between training task improvement,
neuropsychological improvement and functioning measures. Conclusions: this
suggests a complex, multifactorial relationship between CR, cognitive and functional
change.