Nicotine, alcohol and drug dependence and psychiatric comorbidity: Results of a national household survey

Dr Michael Farrell, Senior Lecturer and Consultant Psychiatrist, National Addiction Centre, Institute of Psychiatry and Maudsley Hospital, 4 Windsor Walk, London SE5 8AF, UK. e-mail: [email protected]

Declaration of interest

None. Funding detailed in Acknowledgements.

There is a consistent finding that substance misuse disorders and other psychiatric disorders are strongly correlated with increased levels of service utilisation (Kessler et al, 1997). The combination of a substance use disorder and other psychiatric disorder is recognised to be increasingly common with the increased use of non-prescribed drugs over the past two decades. It seems likely that substance misuse can activate new psychiatric disorders and aggravate current disorders. Comorbidity has significant implications in service delivery (Johnson, 1997).

Having one psychiatric disorder significantly increases the risk of having multiple psychiatric disorders (Kessleret al, 1997). The relationship between psychiatric disorders, substance consumption, misuse and dependence has been the subject of a large-scale epidemiological study (Helzer & Pryzbeck, 1988; Regier et al, 1990; Robins & Regier, 1991; Kessler et al, 1994). The issue of comorbidity of substance use disorders and other psychiatric disorders has become a major policy issue (Hall & Farrell, 1997). The British Psychiatric Morbidity Survey is the largest programme of epidemiological research on the prevalence of psychiatric disorders conducted to date in the UK (Meltzer et al, 1995; Jenkins et al, 1997a , b ). The comparison of the prevalence of nicotine, alcohol and drug dependence across prison, homeless and institutional populations is reported elsewhere (Farrell et al, 1998).

METHOD

National survey methodology

A national survey of psychiatric morbidity was conducted in Great Britain (Meltzer et al, 1995) to determine the level of major and minor psychiatric morbidity in the population. The sample was drawn to represent all of Great Britain except the Highlands and Islands of Scotland. Private households with at least one person aged 16-64 years were identified. In all, 15 765 private households were identified and provided 12 370 adults eligible for interview, of whom 10 018 were interviewed. Only one eligible adult (i.e. aged 16-64 years) was interviewed in each household, systematically selected by the Kish grid method (Kish, 1965). This is part of a large programme of surveys to estimate levels of psychiatric morbidity...