Objective: PsiTri is a new web-based database of randomised or possibly randomised trials on treatment, prevention and improvement of mental health and behavioural problems and conditions. The study-based PsiTri is derived from the specialised registers of five Cochrane Mental Health Groups; Cochrane Dementia and Cognitive Improvement Group, Cochrane Depression Anxiety & Neurosis Group, Cochrane Developmental, Psychosocial and Learning Problems Group, Cochrane Drugs and Alcohol Group, and Cochrane Schizophrenia Group. PsiTri is the first product of the EU-PSI project funded by the 5th framework of the European Commission. The objective of this survey is to present descriptive data on the content of the pooled trial database.

Methods: The PsiTri database at www.psitri.helsinki.fi was surveyed March 15, 2002, when the first 3,738 trials had been included in the database.

Results: 85,0 % of the trials have been classified as RCTs (randomised controlled trials) according to Cochrane criteria. A vast majority (93.0 %) of the trials had recruited adults only. The median number of participants randomised was 49 (interquartile range 26-91). 70.4 % of the trials were performed in a double-blind fashion, and 57,4 % reported on drop-outs or withdrawals.

Conclusion: Although this preliminary dataset may not be totally representative of the final dataset to be collected, these data highlight the need for more mental health trials in children, adolescents, and elderly. The data also illustrates the magnitude of the problem of underpowered RCTs in psychiatry, as well as the need for further training of trialists to increase the use of blinded assessments and the need for considerable improvement of drop-out reporting. On the other hand, the PsiTri register shows that an impressive volume of randomised mental health trials exist and underscores the need for a more effective dissemination of mental health intervention research.