Individualized metacognitive therapy for delusions: A randomized controlled rater-blind study.

Area of Science:

• Psychiatry
• Clinical Psychology

Background:

• Growing interest in theory-driven interventions for delusions.
• Focus on specific factors contributing to delusional beliefs.
• Metacognitive therapy (MCT+) as a manualized intervention addressing cognitive biases.

Purpose of the Study:

• To evaluate the efficacy of individualized metacognitive therapy (MCT+) for delusions.
• To assess the impact of MCT+ on delusion severity and cognitive biases.
• To compare MCT+ with a control intervention in a randomized controlled trial.

Main Methods:

• 92 patients with delusions randomized to MCT+ or a control intervention.
• 12 twice-weekly sessions delivered in a rater-blind design.
• Assessment of psychopathology and cognitive biases at baseline, 6 weeks, and 6 months.

Main Results:

• MCT+ group showed significant reduction in delusion severity and improved self-reflectiveness at 6 weeks (medium effect size).
• Trend-wise improvement in probability thresholds for decision-making in the MCT+ group.
• Effects were more pronounced in patients attending at least 4 sessions; however, no significant differences at 6-month follow-up.

Conclusions:

• MCT+ appears to facilitate earlier improvements in delusions and associated cognitive biases.
• Absence of long-term effects may be due to floor effects or the need for interventions promoting sustainability.
• Limitations include potential unequal therapeutic effort and lower baseline delusion severity in the MCT+ group.