Gambling behaviour was measured using the Problem Gambling Severity Index,2 a validated self-report instrument that measures gambling behaviour over the preceding 12 months. It is derived from the Canadian Problem Gambling Index and consists of nine items. For each item respondents answer on a four-point scale (0 never, 1 sometimes, 2 most of the time, 3 almost always). Total scores therefore range from 0 to 27, where 0 indicates no gambling problem, 1 or 2 a low risk of gambling problems, 3–7 moderate risk and 8 or over severe risk. The PGSI was mailed to 3500 BDRN participants in April 2011 and a reminder was sent 1 month later; 793 participants (23%) completed and returned the questionnaire.
