Common mental disordersIn a review and analysis of multinational epidemiological surveys, Kessler (2001) found that overall approximately 50% of current drug dependence could be attributed to pre-existing mental disorders. The figure was slightly higher for men (54.7%) compared with women (47.8%). The contributing pre-existing disorders differed for the sexes with conduct or antisocial personality (ASPD) disorders being most salient for men (51.2% of risk) ahead of anxiety (17.5%) and mood disorders (9.6%). For women there was a more even spread of risk across conduct or ASPD (34.8%), anxiety (25.9%) and mood disorders (27.0%). As pointed out by Kessler, there are limitations to the findings from epidemiological surveys, but the finding that common mental disorders tend to precede substance abuse disorders is also corroborated in clinical studies (see also Chapter 4).
Although the results from the epidemiological studies do not prove causation, they point to the likelihood that early intervention for common psychiatric disorders may have an impact on drug dependence rates at a later stage. The analysis by Kessler (2001) showed that only active, not remitted, disorders related to onset of drug use — a strong argument for early intervention for mental disorders. Much effort directed at preventing drug use in schools has met with little success (Ennett et al., 1994); yet studies have shown that large-scale interventions in childhood can affect the course of such common disorders as anxiety (Chapter 4) and depression (Cicchetti & Rogosch, 1999). There is also a tendency to focus on the more disruptive conduct disorders in school populations with much less interest in the internalising, anxiety and mood, disorders. This has particular relevance for females for whom the anxiety and mood disorders are much more likely to precede drug dependence. Furthermore, research suggests that treatment outcomes may be worse for women compared with men with common mental disorders and substance abuse (Lynskey, 1998), so that it may be particularly important that steps are taken to prevent the common disorders amongst women.
These data argue strongly for greater emphasis on screening and treatment of the common mental disorders in childhood with likely benefits to be found in the long-term reduction of numbers presenting as adults with single and comorbid substance use and mental disorders.
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PsychosesIn a recent review Schaffner and McGorry (2001) explored developments regarding early detection and interventions for psychotic disorders. They concluded that there are promising treatments awaiting ethical approval which may significantly and positively change the prognosis for people suffering from psychotic disorders. Early interventions can be introduced at the prodromal or first psychotic episode phase; the former attracting considerable ethical debate as it requires antipsychotic treatment (and the stigmatisation associated with identification of such illnesses) before onset of the illness. However, there is evidence of both biological and psychosocial damage resulting from the symptoms of the prodrome and first episode psychosis which provides a compelling argument for their prevention. Research on early interventions at first psychotic episode is less problematic ethically and such interventions have generally been regarded as beneficial (Wyatt & Henter, 2001).
In contrast to the continuing medicalisation of services, the work done on psychosocial interventions suggests that these can also improve outcomes and there needs to be a re-orientation of services so that staff are trained in the effective psychotherapeutic interventions now available for serious mental illness (Thornicroft & Susser, 2001). Psychotherapeutic interventions are far less controversial in this area because they do not pose the risks that antipsychotic medications do in terms of medical side-effects. Thus it is important that staff in psychiatric and substance abuse services are trained and funded to implement evidence-based practices for early intervention. Such practices need to be implemented across the board in psychiatric and drug and alcohol services in the form of standardised procedures, rather then waiting for individual service providers to decide to take up these effective practices.