Objective To examine the association between trends in antidepressant prescribing and suicide rates in Australia for 1991-2000. Design Analysis of databases of suicide and rates of antidepressant prescribing according to age and sex. Setting Australian Bureau of Statistics data, sales data from the Australian pharmaceutical industry, prescribing data in general practice. Subjects Men and women aged 15 years and over in 10 year age groups. Main outcome measures Trends in suicide rates and trends in antidepressant prescribing. Association measured by Spearman's rank correlations. Results While overall national rates of suicide did not fall significantly, incidence decreased in older men and women and increased in younger adults. In both men (r s = − 0.91; P < 0.01) and women (r s = − 0.76; P < 0.05) the higher the exposure to antidepressants the larger the decline in rate of suicide.

Several studies over the past 15 years have compared the number of fatal poisonings due to antidepressant drugs in the United Kingdom with drug use statistics to derive a fatal toxicity index: deaths per million prescriptions.1 2 Greater than 10-fold differences in the index have been shown between tricyclic antidepressants and even larger differences between some tricyclics and newer antidepressants. Explanations have focused on preference for noradrenaline or serotonin reuptake blockade, although only weak correlations have been observed 2 and the explanation is toxicologically implausible. 1 In the late 1990s the use of newer serotoninergic antidepressants increased dramatically. Some data show that venlafaxine in particular may not be as safe in overdose as other serotoninergic drugs, with reports of deaths, arrhythmias, and seizures. 3 We aimed to establish the relative frequency with which venlafaxine and other new antidepressants result in fatal poisoning. Methods and resultsWe obtained the number of deaths in Scotland, England, and Wales due to acute poisoning by a single drug, with or without co-ingestion of alcohol, from the General Register Office for Scotland and the Office for National Statistics for the years 1993-9. We used the number of prescription items for England, Wales, and Scotland supplied by the respective departments of health for these years as a measure of relative drug use. Use in hospital is not included, but prescribing of antidepressants overwhelmingly occurs in general practice. For each drug we calculated a fatal toxicity index expressed as deaths per million prescriptions. We calculated the lower and upper 95% confidence limits for the index by using exact confidence intervals for the deaths. The table lists the drugs in descending order of fatal toxicity index within British National Formulary drug classes. The serotoninergic drug class overall had a much lower index than the tricyclic antidepressants and monoamine oxidase inhibitors, but venlafaxine had a higher index than the individual and combined results of other serotoninergic drugs. CommentThe most striking new observation is that the fatal toxicity index for venlafaxine is higher than those for other serotoninergic antidepressants and similar to those for some less toxic tricyclic antidepressants. This raises the question of whether venlafaxine should continue to be a first line drug in patients with suicidal ideation. Our results also confirm previously reported large differences in fatal toxicity index between other antidepressant drugs.

ObjectiveTo determine the pattern of use of antidepressant drugs in the Australian community, 1990–1998, and to compare this with those of other developed countries. DesignRetrospective analyses of prescription and sales data, together with information about patient encounters for depression (from an ongoing survey of service provision by general practitioners) and population‐based prevalence estimates for affective disorders (from community health surveys). Main outcome measuresNational and international consumption of antidepressants, expressed in defined daily doses (DDDs) per 1000 population per day. Changes in both the frequency of general practice patient encounters for depression and population‐based prevalence estimates for affective disorders. ResultsDispensing of antidepressant prescriptions through community pharmacies in Australia increased from an estimated 12.4 DDDs/1000 population per day in 1990 (5.1 million prescriptions) to 35.7 DDDs/1000 population/day in 1998 (8.2 million prescriptions). There has been a rapid market uptake of the selective serotonin reuptake inhibitors (SSRIs), accompanied by a decrease of only 25% in the use of tricyclic antidepressants (TCAs). In 1998, the level of antidepressant use in Australia was similar to that of the United States, while the rate of increase in use between 1993 and 1998 was second only to that of Sweden. In Australia, depression has risen from the tenth most common problem managed in general practice in 1990‐91 to the fourth in 1998‐99, and the number of people reporting depression in the National Health Surveys (1995 v 1989–90) has almost doubled. Of the prescriptions dispensed in 1998 for antidepressant drugs subsidised by the Pharmaceutical Benefits Scheme, 85% were written by general practitioners, and 11.2% by psychiatrists. ConclusionsAs in most developed countries, antidepressant use increased between 1990 and 1998. The rapid market uptake of the new antidepressants, particularly SSRIs, is likely to have been driven by increased awareness of depression, together with availability and promotion of new therapies.

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The Australian government offers its citizens subsidies on a select list of pharmaceuticals. For a drug to qualify for inclusion on this list, its manufacturer must demonstrate that the drug is both clinically effective and cost-effective. In part, this measure, along with others, was introduced to improve clinical and economic outcomes. Although this evidence-based system has provided transparency and consistency in decision making about which drugs will be covered, it may not have contained the rate of increase in drug costs.