Since substance use, misuse, harmful use and dependence are associated with considerable mortality and physical and psychological morbidity, the multiple and complex interactions of substance misuse with health will be explored.

Gender differences in substance use accrued from prevalence studies will be outlined and will be presented in the context of predisposing or complicating psychological symptoms or psychiatric syndromes. Observations that women are more likely to report a comorbid psychiatric condition than males, especially depression or borderline personality disorder but also impulsivity, aggression and disinhibition, anxiety, psychotic illness, post-traumatic stress disorder (as a result of early life stress and physical abuse) and eating disorders, will be examined in relation to the course and outcome of illness. Evidence for the high risk behaviours and chaotic life style that may be associated with comorbidity, such that self-harm may result, with eventual suicide, will be described.

In view of the fact that patients with comorbid conditions have poorer prognosis and place a heavy burden on services because of disengagement, high rates of relapse and re-hospitalisation, serious infections, and homelessness, unemployment, poverty, prostitution, violence, arrest and even imprisonment, it is important to have a grasp of the nature and extent of the problems so that patients can be sensitively managed. The likely impact of these conditions on women and their social roles as mother and carer will be analysed as part of the need to develop effective services, which detect problems early and deliver appropriate interventions which are sensitively managed.