Symptoms of AAD were assessed by the CAGE, originally developed as a screening instrument for medical settings (Ewing 1984), which gives an indication of the presence of symptoms of AAD (Dhalla and Kopec 2007). The CAGE consists of four items that can be answered with ‘yes’ or ‘no’: Have you ever felt that you should Cut down your drinking?; Have people Annoyed you by criticizing your drinking?; Have you ever felt bad or Guilty about your drinking?; Have you ever had a drink in the morning (as an ‘Eye opener’) to steady your nerves or get rid of a hangover? In 2009/2010, there were three response categories: ‘yes, during the last year’; ‘yes, not during the last year’. These two yes categories were recoded into one, since its frequency was comparable to the frequency of the single yes categories in earlier years. If one of the four CAGE items was missing (N = 64; 0.8%), its value was imputed based on the mean of the three other answers. In case of two or more missing answers (N = 30; 0.4%), the CAGE was set to missing.
