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

BACKGROUND: 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 evidence-based 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. A total of 75 individuals with psychotic disorders were randomized to a combination of strategy-based and drill-and-practice CR or wait-list control, 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. RESULTS: Compared with treatment as usual, 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 the 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 (Quality of Life Scale), 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, and cognitive and functional change.

Impact of intellectual status on response to cognitive task training in patients with schizophrenia.

Cognitive remediation is a promising rehabilitation procedure for people with schizophrenia, but very little is known about who can benefit. In the current analyses, we examined the role of pre-morbid and morbid intellectual function in predicting response to cognitive remediation in a sample of 152 patients diagnosed with schizophrenia or schizoaffective disorder. They were participants in a trial of work therapy and cognitive remediation and had been randomized to receive either Neurocognitive Enhancement Therapy with Work Therapy (NET+WT) or Work Therapy only (WT only). For the current analyses, patients were divided into three intellectual subgroups based on their pattern of premorbid and morbid deficits (preserved intelligence, compromised intelligence, and deteriorated intelligence), and their cognitive remediation outcomes were examined. Cognitive remediation response was measured in two ways: normalization of performance on a computerized training task, and pre-post neuropsychological test performance. Subjects in NET+WT showed greater improvement in cognition than those in WT only, but response differed by intellectual group. For patients in the compromised group, those in NET+WT showed a significantly higher proportion of task normalization than those in the WT only condition, but no such differences were found with the preserved and deteriorated intellectual groups. For patients in the preserved and deteriorated intellectual groups, those in the NET+WT condition showed significantly greater improvement in the analysis of pre-post neuropsychological test performance, but this difference was not found in the compromised intellectual group. These findings suggest that the compromised intellectual group, which had the lowest frequency of normal performers at intake, benefited from NET by achieving dramatic increases in normalization, but that they had difficulty in generalizing these gains to untrained tasks. Those in the preserved and deteriorated intellectual groups were more successful in generalizing their training.

Cognitive training of verbal memory using a dichotic listening paradigm: impact on symptoms and cognition.

OBJECTIVE: The objective was to investigate the impact of a verbal memory training task on psychiatric symptoms and cognition in schizophrenia. METHOD: As part of a larger, 6-month cognitive remediation program, 57 patients with schizophrenia were randomly assigned to receive performance-based, hierarchical training on a verbal memory task based on a dichotic listening (DL) with distracter paradigm. These patients were compared with 68 patients who had been randomly assigned to a control condition. RESULTS: Training on the DL task was not associated with changes in general psychopathology or auditory hallucinations (AH) specifically. Training was associated with improvements in verbal memory, but not attention. CONCLUSION: The current investigation adds to the growing literature on the effectiveness of cognitive remediation training and indicates that training on the DL task enhances verbal episodic memory. The results do not support the use of DL training as a method for reducing AH.