13 September 2007

Tobacco associated with new mental illness in prospective study.

Smoking is associated with first-ever incidence of mental disorders: a prospective population-based study. Cuijpers P, Smit F, ten Have M, de Graaf R.

Addiction 2007 102:1303-9

Dear Colleagues,

This month�s Addiction journal contains a most important study, almost hidden at the back of an issue packed with other meaty items. For the first time, I believe, the intrepid Dutch group (NEMESIS or Netherlands Mental Health Survey and Incidence Study) has found a significant association between tobacco smoking and mental illness. With up to 80% response rates in over 5000 Dutch adults this study looked at who was smoking and/or had a mental illness at the start, one and three years (along with many other variables).

A significant association found was between smoking and the development of anxiety, dysthymia and new alcohol abuse. Unlike cannabis, no association was found with psychosis. Considering the prevalence of smoking the findings are still highly significant. The prospective nature and accounting for confounders in these findings supports a causal association from the tobacco, yet no dose relation was found. Hence further research will need to look at these areas, according to the authors. Also, a rational pathogenic pathway from smoking to mental disease needs to be confirmed. It may not be a coincidence that some mental illness is increasing in extent and severity in certain countries.

Two other recent studies have apparently shown links between smoking and dementia (Holland; ANU). The Erasmus Medical Centre in Holland found a 50% increase in dementia in age matched smokers. The links with lung cancer and arterial disease are well known. An Adelaide hospital has apparently restricted elective surgery for those who continue to smoke. This month�s Addiction journal reports the same thing from the NHS in Leicester, England (p1331). Yet another report in this issue points to equal outcomes for those who quit abruptly and those who cut down gradually (Hughes p1326).

So the ground-swell against tobacco continues, based on its being the largest single reversible cause of death and morbidity in our society. Over 19,000 Australians die each year from tobacco related illnesses. While we know how to treat established nicotine addiction, we still do not know why people smoke and whether there are safer pharmaceutical alternatives and when these may be appropriate. One innovation which should be considered in Australia is the oral tobacco wad (�chewing tobacco� or Swedish �snus�) which may offer more advantages than harms, although it probably just as addictive as the smoked variety.

Comments by Andrew Byrne ..

Van Laar M, van Dorsselaer S, Monshouwer K, de Graaf R. Does cannabis use predict the first incidence of mood and anxiety disorders in the adult population? Addiction 2007 102:1251-1260