PhD defence Y. (Yvonne) de Jong

Below is a brief summary of the dissertation:

Screening for Psychosis in Adolescents: Early Detection is Possible, but Tailored Approaches Are Needed

This dissertation investigates how psychosis can be detected early in adolescents aged 12 to 18. Psychosis is a serious psychiatric condition that often begins during adolescence. Early identification of young people at high risk—those with an Ultra High Risk (UHR) status—can help prevent significant suffering and reduce healthcare costs.

The standard screening method, which includes the PQ-16 questionnaire and a follow-up assessment (CAARMS), works well for adolescents. However, psychosis-like experiences are more common in this age group and are often temporary, without leading to full-blown psychosis.

Key Findings:

- The PQ-16 is reliable and easy to implement for adolescents.

- Adjusting the cut-off score (from 6 to 7 items agreed upon) improves the predictive value of the PQ-16.

- Combining questionnaires for adolescents (YSR) and parents (CBCL) with the PQ-16 strengthens predictive accuracy.

- Some adolescents recover within a year, while others either continue to be at risk or develop actual psychosis.

- Adolescents report seeing or hearing things more often than adults, but most do not develop psychosis, even though they experience unusual perceptions.

Conclusion: Screening for psychosis in adolescents is feasible and provides results comparable to those in adults. Further research is needed to explore effective treatments and interventions that could prevent psychosis and reduce the impact of unusual experiences.