Understanding unusual sensory experiences: a randomised experimental study of a school-based intervention for adolescents.

Background: One in ten young people experience unusual sensory experiences (USE), such as hallucinations. From a cognitive perspective, the appraisal of USE determines the impact of these experiences. Negative appraisal, as well as other psychological processes (e.g. thinking flexibility, maladaptive schemas, anxiety/depression), is associated with more distress. Our aim was to (a) develop a universal single-session school-based intervention on USE for adolescents and (b) evaluate the effect of the intervention on appraisals of and help seeking intentions for USE.

Methods: A randomised controlled experimental design with a one-month follow-up was used to test the effectiveness of the intervention in one school. Students (n = 223) aged 12-13 were randomised by class to a single-session intervention on USE or a control intervention (generic mental wellbeing). Participants completed measures of appraisals of and help-seeking intentions for USE at pre- and postintervention and at one-month follow-up. They also completed measures of schemas, thinking flexibility and anxiety/depression at preintervention.

Results: Overall, 190 adolescents completed the main outcome measures at all three points. The intervention on USE led to a significant (p < .05) increase of positive appraisals of USE compared with the control, with effects sustained at one-month follow-up. The intervention on USE did not lead to significantly greater help-seeking intentions for USE (p = .26). Adolescents' schemas were associated with appraisals and slow thinking and anxiety/depressive symptoms with help-seeking behaviour for USE.

Conclusions: A single-session universal school-based intervention shows promise by improving appraisals of USE. Further research is required across different school populations.