The Malmo-modified Michigan Alcoholism Screening Test (Mm-MAST; Kristenson and Trell, 1982) is a 9-item self-report scale of current drinking patterns and problems designed for application in Nordic cultures (Seppa et al., 1999). Representative items include taking a drink before going to a party, increased tolerance over time, and having difficulty not drinking more than one’s friends. Our scale added 2 items more directly overlapping DSM diagnostic criteria: finding it hard to stop after having had a drink and feeling that someone close to you thinks you should drink less. Each of these questions was asked of “current and past drinking habits” and had a “Yes” or “No” response option. For those twins who answered at least 9 of the 11 items, we calculated a Mm-MAST score by taking the average response (yes/no) across the number of items answered. This scoring method permitted us to retain participants who completed the majority of the items but who may have neglected to answer a few of them.
