In this study, the researchers examined data from a large population study in Sweden. Participants were 4,991 respondents who reported gambling in the past 12 months. The results showed that some forms of gambling were more closely associated with problem gambling. These included electronic gaming machines (EGMs), casino games, bingo and poker. People with problem gambling spent more time and money gambling. They were also more likely to play multiple forms of gambling. However, about 40% of those participants gambled regularly on only one gambling form. Thus, gambling regularly on a specific form of gambling might be the source of harm for many people with problem gambling. Participants who gambled regularly on EGMs were most likely to have problem gambling, regardless of whether they engaged in additional gambling forms. For most other gambling forms, the risk of problem gambling increased if people also engaged in additional gambling forms.