“…The reported studies applied a variety of different exclusion criteria as screening items such as (1) having ever gambled in life (Bakken et al, 2009;Cox et al, 2004;Welte et al, 2008), (2) having participated in any kind of gambling activity in the past year (Doiron and Nicki, 2001;Huang et al, 2007;Philippe and Vallerand, 2007;Wiebe and Cox, 2005), (3) having gambled a certain amount of money in the past year (Becoña Iglesias, 2004;Bühringer et al, 2007), (4) having either gambled weekly or spent a certain amount of money in the past year (Buth and Stöver, 2008) or (5) having either (a) gambled weekly, (b) ever tried to control gambling, (c) ever spent a certain amount of money, (d) did so regularly or (e) gambled regularly for a certain time period a day (Brodbeck et al, 2009). Given that a tendency to conceal the extent of gambling involvement is characteristic of PG, subjects concerned may not answer truthfully to screening questions about their gambling behaviour (Petry, 2003).…”