This study is the first to determine the prevalence of gambling problems in a UK sample with bipolar disorder, as well as exploring the associations between risk of problem gambling and lifetime clinical variables. Its strengths include the large, representative sample of patients with bipolar disorder and the rich clinical history data available concerning these patients. However, there were also several limitations. First, although it is widely used and validated, the PGSI is a self-report measure subject to a degree of social desirability and recall bias. Such bias was minimised at least to some extent because all questionnaires were completed in a private and confidential manner, encouraging honest reporting, and gambling behaviours were assessed over the previous 12 months only. Second, 23% of invited BDRN participants returned the PGSI questionnaire, which inevitably introduces responder bias to the data. It is difficult to know whether this bias over- or underestimates the prevalence of gambling problems. People who are currently gambling might be more likely to be interested in the research and complete the questionnaire; conversely, they might prefer not to disclose
