Transdiagnostic treatment?
Results showed a “small to moderate” effect size (ES) in global proximal outcomes (g = .39; 95% confidence interval, .25-.53; P < .001; 38 reports).
When proximal outcomes were analyzed separately, the largest ES was found for delusions; smaller ES values were found for hallucinations and cognitive biases.
Newer studies reported higher ES values for hallucinations, compared with older studies (β = .04; 95% CI, .00-.07).
ES was small to moderate for distal outcomes (g = .31; 95% CI, .19-.44; P < .001; 26 reports). “Small but significant” ES values were shown for self-esteem and negative symptoms, small to moderate for functioning, and small but nonsignificant for quality of life (QOL).
The researchers also analyzed RCTs by comparing differences between the treatment and control groups in scores from follow-up to post-treatment. Although the therapeutic gains made by the experimental group were “steadily maintained, the ES values were “small” and nonsignificant.
When the difference in scores between follow-up and baseline were compared in both groups, small to moderate ES values were found for proximal as well as distal outcomes.
“These results further indicate that net therapeutic gains remain significant even 1 year following MCT,” the investigators note.
Lower-quality studies showed significantly lower ES values for distal (between-group comparison, P = .05) but not proximal outcomes.
Overall, the findings suggest that MCT is a “beneficial and durable low-threshold intervention that can be flexibly delivered at minimal cost in a variety of contexts to individuals with psychotic disorders,” the researchers write.
They note that MCT has also been associated with positive outcomes in other patient populations, including patients with borderline personality disorder, depression, and obsessive-compulsive disorder. Future research “might consider investigating MCT as a transdiagnostic treatment,” they add.
Consistent beneficial effects
Commenting on the study, Philip Harvey, PhD, Leonard M. Miller Professor of Psychiatry and Behavioral Sciences and director of the Division of Psychology, University of Miami Miller School of Medicine, noted that self-awareness and self-assessment are critically important features in patients with serious mental illness.
University of Miami Miller School of Medicine
Dr. Philip Harvey
Impairments in these areas “can actually have a greater impact on everyday functioning than cognitive deficits,” said Dr. Harvey, who is also the editor-in-chief of Schizophrenia Research: Cognition. He was not involved with the current meta-analysis.
He noted that the current results show that “MCT has consistent beneficial effects.”
“This is an intervention that should be considered for most people with serious mental illness, with a specific focus on those with specific types of delusions and more global challenges in self-assessment,” Dr. Harvey concluded.
Funding was provided by the Canada First Research Excellence Fund, awarded through the Healthy Brains, Healthy Lives initiative at McGill University. Ms. Penney reported no relevant financial relationships. Disclosures for the other investigators are listed in the original article. Dr. Harvey reported being a reviewer of the article but that he was not involved in its authorship.