Table 1 shows the prevalence of problem gambling in bipolar disorder and major depression. The prevalence of at least moderate risk of problem gambling in bipolar disorder was 10.6% (95% CI 8.21–12.99) and of severe risk was 2.7% (95% CI 1.44–3.96). In major depression the prevalence of at least moderate risk of problem gambling was 5.2% (95% CI 1.14–9.26) and of severe risk it was 0.9% (95% CI 0.83–2.63). The difference between bipolar disorder and major depression in the prevalence of both at least moderate risk and severe risk of problem gambling did not reach statistical significance (P = 0.087 and P = 0.336 respectively). The mean PGSI score in the moderate-risk group with bipolar disorder was 4.24 (95% CI 3.92–4.72; range 3–7, median 4) and in the severe-risk group with bipolar disorder it was 14.06 (95% CI 11.35–16.77; range 8–22, median 13). The sample size with severe risk of problem gambling with bipolar disorder was too small for further analysis (n = 17); therefore, all further analyses described below consider the combined group of participants with bipolar disorder and moderate to severe risk of gambling problems.
