Prediction of Social Psychiatric and Treatment Related Outcomes in the Spectrum of Psychotic Disorders

Psychotic disorders are severe and potentially disabling mental disorders which rank among the world's top 10 causes of chronic disability and produce high healthcare costs. First-line treatment with antipsychotic medication is associated with only medium effect sizes for positive symptoms and several limitations. Research has thus increasingly embraced new and complementary treatment approaches, namely the early detection and intervention research and the development of psychological interventions. This thesis aimed to address unresolved research questions in these areas. Article 1 and 2 focused on the early detection and intervention of psychotic disorders and investigated predictors of study drop-out, service disengagement, and long-term clinical and functional outcome in patients at clinical high risk for psychosis (CHR-P). Article 3 analyzed moderators of individualized Metacognitive Training (MCT+), a theory-driven intervention designed to improve delusional symptom severity. In Article 1, 36% of CHR-P patients dropped out and/or disengaged within 5 years. A late study inclusion period, associated with more frequent follow-ups and higher participation burden, was predictive for higher risk of drop-out and disengagement. In Article 2, remission from CHR-P status after 10 years was estimated as 51%. Better baseline psychosocial functioning was associated with a higher rate of remission. However, only a minority of patients fully recovered clinically and functionally. In Article 3, the occurrence of the jumping-to-conclusions bias and low self-esteem were associated with larger improvements over time in MCT+ compared to an active control intervention. Article 1 and 2 underline the importance of individually tailored treatment planning and call for the right balance between too high-frequency assessments on one hand, and a lack of treatment care for patients experiencing long-term clinical symptoms and functional impairments on the other. The findings of Article 3 provide useful criteria for selecting patients who might particularly benefit from MCT+.