Background Significant resources are used to produce health information but little is known about consumer information needs, particularly in mental healthcare. The Internet is increasingly being used, particularly for mental health topics. Methods Literature reviews in the areas of health information needs and the role of the Internet in healthcare; in-depth interviews to explore the experience of mental health users with health information and with the Internet; and a population survey to investigate the interview findings and provide generalisable data on information needs. Results There is very little existing research in the area of mental health information needs. Much of the literature around consumer use of the Internet for health information focuses on issues of quality and access. The most common information needs were: what the problem is; what treatments are available; how to help oneself; where to get help from; what has caused the problem; and the future course of the problem. The sources of information considered most accurate and most likely to be used were general practitioners and mental health professionals. The Internet was not ranked highly for accuracy, but was one of the sources likely to be used. The presence of mental health distress was significantly associated with the use of the Internet for mental health information, after adjustment for age, sex and educational level. Another need is to hear about the experience of others, and this was a particular role for the Internet. This need can be subdivided into 'universality', 'installation of hope', and 'empathy and understanding'. Conclusions and implications Mental healthcare users are poorly served by current health information provision. The results provide support for a stronger practitioner-patient partnership. Policymakers should address the needs identified in this work, including the need to hear about other people's experience. Further research investigating health-related use of the Internet is required.