AbstractObjective: The main aim of this project was to examine the effect of Cognitive Behavioural Therapy (CBT) in reducing symptoms for patients with an Ultra High Risk (UHR) for developing psychosis and for patients with a First Episode Psychosis (FEP). Methods: Systematic search for relevant randomized controlled trials in the major databases Medline, Pubmed and PsychInfo. Experts in this field of science have been contacted and reference lists of relevant papers have been scanned. Results: Some studies show a significant short-term effect of CBT for this group of patients. However, the studies are methodologically weak and the studies are not directly comparable. No significant long-term effects are found. Conclusions: At this time we can not conclude whether CBT is effective for these two groups of patients or not. More comparable and methodologically stronger studies are needed..