Severe stressful experiences, such as the death of a loved one, break-up of a relationship, or job loss usually go along with a destabilization of living conditions and an elevated level of unpleasant feelings. In such changing life situations, alcohol use, particularly heavy use, can reduce negative feelings and, in the beginning, dampen unpleasant physiological phenomena, such as sleeplessness or restlessness [2]. Therefore, drinking is frequently used as a means to cope with stress [2], [12]–[14]. However, growing tolerance towards the effects of alcohol can lead to increased amounts being drunk, thereby aggravating life stress and altering circadian rhythmicity [15]. Accordingly, life stress is regarded as a major environmental risk factor for both, heavy drinking [16], [17] and disturbed circadian rhythmicity. Possible explanations for this link include biological mechanisms, by which alcohol use alters the physiological reaction to stress, namely the hypothalamic-pituitary-axis response, or vice versa [4], [17], [18].
