The findings suggest that behavioural indicators could be used as initial markers of possible problem gambling among youth. Among Finnish youth aged 12-14 years, gambling behaviour began to cause harm when they gambled beyond 2-3 times per month, spent over €2 per week on gambling, spent more than €8 in any 1 day on gambling, and gambled on more than two different games per year. Among youth aged 15-17 years, gambling behaviour began to cause harm when they gambled beyond once per week, spent over €4 per week on gambling, spent more than €12 in any 1 day on gambling, and gambled on more than two different games per year. For both age groups, amount of money spent on gambling was the strongest indicator of possible problem gambling.
