Description

There is strong evidence for the occurrence of substance misuse and comorbid psychiatric disorders in community and clinical settings. The pattern of this comorbidity varies between comorbid mood, anxiety and personality disorders in patients accessing addiction services and comorbid alcohol, cannabis and cocaine misuse in patients accessing general psychiatric services. Comorbidity is associated with  increased risk for violence, suicide and worse clinical and social outcome. Whilst its diagnosis remains challenging, diagnostic guidelines including DSM – IV derived ones offer a major advance in offering criteria for distinguishing substance induced (organic) and independent (primary) psychiatric cormorbidity.  Treatment is guided by evidence-based and experience-based approaches which should be optimally provided in intergrated models of services where substance misuse and cormorbid psychiatric disorders are managed by professionals who are skilled in both domains whether working in community/hospital settings or addiction/general psychiatric services.

The co-occurrence of substance misuse and other mental disorders has been increasingly recognised as a major public health problem in recent years; the term dual diagnosis has been introduced into the psychiatric lexicon to describe this phenomenon. This is unfortunate, as the same term has also been used to denote the co-occurrence of mental handicap and mental illness. Moreover, it is often confined to the combination of severe mental illness (psychotic disorders) and substance misuse. A better term to describe these phenomena is co-morbidity. The recent recognition of dual diagnosis as a problem can be attributed to a number of reasons. Firstly, there was the development of drug abuse services in the late 1960s, with the establishment of special clinics, separately from the development of general psychiatric services, with little interface between them. Secondly, the move from hospital to community care for treatment of people with severe mental disorders has exposed them more to the risk of developing alcohol and drug problems, and thus compounding their psychopathology and disabilities. Thirdly, there is the high risk for self-harm and harm to people in the community in two distinct populations: the seriously mentally ill within general psychiatric services and those with severe personality disorders within addiction services. This results in a tendency to disown these problems within the service concerned together with an expectation that each group belongs to the counterpart service; the result is that those patients within these groups are likely to fall between the cracks.