Distressing mental images are common in people with psychosis. The central role of metacognitive difficulties in psychosis suggests that metacognitive interventions with imagery properties could play a central role in managing distressing mental imagery. A brief imagery-based metacognitive intervention was developed to target the control mechanism of distressing mental images in psychosis.

A fixed baseline case series was designed to investigate whether the intervention was acceptable, feasible and effective.

Eight participants who met criteria for a schizophrenia spectrum diagnosis and experienced distressing future-oriented mental images took part in the case series, which consisted of three phases; baseline, intervention, and follow-up. Symptoms of anxiety, depression, persecutory delusions and schemas were assessed pre- and post-intervention, and qualitative feedback was collected at follow-up.

The metacognitive intervention was feasible, acceptable, and rated as highly satisfactory. One participant dropped out at the baseline phase. No adverse events were reported. Positive change scores with a decrease in symptoms were reported for anxiety, depression, persecutory delusions, and schemas. Tau-U analysis showed positive trends and high effect sizes on mental imagery characteristics at follow-up.

Our findings suggest that it is acceptable and feasible to engage people with psychosis in a brief imagery-based metacognitive intervention and that positive change can be achieved. Further studies are needed to replicate and clarify the findings of our study and develop the evidence base for this intervention.