Objective: The aim of this study was to assess health professionals' beliefs about the helpfulness of a broad range of possible interventions for mental disorders. Method: The study involved a postal survey of 872 general practitioners (GPs), 1128 psychiatrists and 454 clinical psychologists. These health practitioners were presented with a vignette describing either a person with schizophrenia or one with depression. The vignettes were taken from an earlier survey of the general public. Respondents were asked to rate the likely helpfulness of various types of professional and non-professional help and of pharmacological and non-pharmacological interventions. Results: Two-thirds or more of each profession agreed that the person with schizophrenia would be helped by GPs, psychiatrists, clinical psychologists, antipsychotic agents and admission to a psychiatric ward. Similarly, two-thirds agreed that the person with depression would be helped by GPs, psychiatrists, clinical psychologists, antidepressants, counselling and cognitive-behavioural therapy. However, there were also areas of disagreement. Psychiatrists were less likely than GPs and clinical psychologists to rate psychological and lifestyle interventions as helpful, while clinical psychologists were less likely to rate specifically medical interventions as helpful. Younger members of the professional groups and female members (who also tended to be younger) tended to rate a wider range of interventions for each disorder as likely to be helpful. Conclusions: Despite areas of broad agreement about treatment, health practitioners were more likely to endorse the interventions associated with their own profession. However, younger members of each profession tended take a broader view. If these age differences represent a cohort effect, health professionals may in the future show greater acceptance of the helpfulness of interventions offered outside their profession. These conclusions are limited by the methodology of the survey, which involved a questionnaire designed for the public rather than professionals.