ABSTRACT
This chapter identifies problems with definitions and other basic methodological considerations when studying the epidemiology of comorbidity. Mental health and substance use problems are a major public health issue. Pressures on health services and the emergence of competing approaches, such as the organisation of mental health services, have both served to emphasise this burden. Many people reporting substance use have experienced mental health problems at some point in their lives, and many individuals with a mental health problem have a history of past or current substance use. Professionals face a particular challenge from mental health–substance use problems, as they combine to produce greater impairment of function and poorer health outcomes than a single diagnosis alone. Life course epidemiology in mental health–substance allows investigators to start testing for intergenerational exposure disease association. Mental health–substance use conditions tend to present with more severe mental health problems.
