The model of the aetiology and maintenance of DSH on which the treatment protocol is based addresses interactions between cognitive, affective, behavioural and interpersonal aspects of DSH. As in other stress-process models, the relationship between vulnerability factors (negative family experiences and biological characteristics), triggering factors, and DSH is mediated by moderating variables (interpersonal problems/lack of social support and individual characteristics: cognitive distortions, affective dysregulation and skills deficits) and mediating variables (negative appraisal, inadequate coping and psychological reactions such as impulsivity). In accordance with Van Praag (1996), we assume that if a person with a marginally functioning serotonergic-system experiences a stressful event he or she is not able to cope with, the production of the stress-hormone cortisol increases, which decreases the level of serotonin. Reduced serotonin activity in the prefrontal cortex as examined by neuroimaging techniques, may be involved in the destabilisation of the regulation of fear, aggression (Van Praag, 1996) and impulsivity (Mann, 1999), since this area of the brain mediates behavioural inhibition. Increased impulsivity may therefore increase the risk of DSH (Van Heeringen, 2001). We assume that in some patients impulsivity and carelessness will be the primary features associated with DSH. In particular, if impulsivity and feelings of hopelessness co-occur, the risk of DSH appears to be high. The recognition of the association between hopelessness and DSH, described here, is in line with the cognitive approach of Williams (2002) stating that over time, among people who perceive they cannot change the stressful situation they are in, despair gradually gains the upper hand and they will show more marked symptoms of depression and hopelessness in particular.The approach as outlined by us, will have advantages compared to approaches based on single psychiatric problems, since it combines the main biological, cognitive, affective, behavioural and interpersonal aspects of DSH.