The population impact on incidence of suicide and non-fatal self harm of regulatory action against the use of selective serotonin reuptake inhibitors in under 18s in the United Kingdom: ecological study

Discussion

We found no evidence of a temporal association between trends in antidepressant prescribing and deaths from suicide or hospital admissions for self harm in young people despite a halving in levels of prescribing after the Medicines and Healthcare products Regulatory Agency’s regulatory interventions in 2003.

These findings contrast with data from the USA, where regulatory action by the US Food and Drug Administration resulted in reductions in prescribing of selective serotonin reuptake inhibitors (SSRIs) to young people in 2003-4 and these were followed by a reversal of previously falling suicide rates. Between 1988 and 2003 mortality rates for suicide in 5-19 year olds in the USA fell from 4.4 to 2.8 per 100 000 population, but in 2004 they increased to 3.2 per 100 000 population.7 That study looked at suicide rates for only one year after the regulatory action, however, and did not study rates of self harm. Preliminary analysis of data released after this study suggested that the trend from 2003 to 2004 did not continue to 2005, with a decline in number of suicides among young people despite continuing reductions in SSRI prescribing.13

The magnitude of changes in prescribing rates during 2003 to 2004 was larger in the UK than in the USA. We found an overall decrease in prescribing rates to 12-19 year olds of around 40%-50% for both SSRIs and total antidepressants between 2003 and 2005, whereas in the USA the decrease for SSRI prescriptions to similar age groups was in the region of 10%-20% over the same period.7 One possible reason for any disparities between the two countries is that if young people in the UK were more likely to have been receiving psychotherapy as well as drugs, any effects of decreasing use of drugs may have been lessened. This is unlikely, however, given the relatively sparse use of psychotherapy in children and young people in the UK.14

We did not find any temporal association between antidepressant prescribing rates and hospital admissions for deliberate self harm. This is contrary to evidence from a meta-analysis of randomised trials, which indicated around a 1.7-fold increased risk of suicidal thoughts or behaviour in children and adolescents taking an SSRI compared with those taking placebo.15 The data presented here indicate a steadily increasing trend in admissions of females and a relatively flat trend for males, with neither responding to the dramatic increase and decrease in prescribing rates occurring between 1999 and 2006, a pattern primarily driven by SSRI prescriptions. The data on hospital admissions lend additional weight to our assessment of a lack of association between trends in antidepressant prescribing and deaths from suicide, especially given that they are based on greater numbers.

Interpretation of these data must take into account the limitations of this study. Firstly, as our study was an ecological one we were limited to analysis of population trends in prescribing and self harm and suicide. Adverse or beneficial impacts of changing levels of antidepressant use may be masked by changing levels of other influences on suicide and non-fatal self harm.16 Secondly, the prescribing and outcome datasets are for different groups of UK countries, and age groups differ. The potential errors introduced by comparing data for different geographical areas are negligible; on the basis of population estimates in mid-2006 from the Office for National Statistics, the population of England made up 84% of the UK population. Trends that include other UK countries will therefore be dominated by those for England. Additionally, regulations by the Medicines and Healthcare products Regulatory Agency cover the entire UK simultaneously, and any impacts on trends in prescribing in England will likely be similar to those elsewhere within the UK. Similarly, in using prescribing rates for 12-19 year olds to infer those for 12-17 year olds, we are unlikely to be introducing any important bias. It is unlikely that changes in prescribing to 18-19 year olds compensate for changes in the under 18s age group affected by the regulatory action. Thirdly, our prescribing data are restricted to prescribing by general practitioners—it is possible that some of the downturn in primary care prescribing was taken up by increased use of antidepressants in secondary care. Analysis of data on antidepressants from hospital and retail pharmacies (prescribed in primary care), however, indicates that hospital prescribing accounts for about only 4% of all antidepressant prescribing, and that this percentage did not vary substantially over the period 2001-6 (all ages) (unpublished results). It is therefore unlikely that our analysis is biased by unmeasured changes in prescribing in secondary care. Finally, our analysis of beneficial and adverse effects of recent advice on antidepressant prescribing are limited to its impact on suicidal behaviour; there might be other adverse or beneficial long term and short term impacts on the mental health and quality of life of young people whose management has changed.

The noticeable change in antidepressant prescribing to young people after the introduction of SSRIs and subsequent regulatory action limiting their use in under 18s in the UK does not seem to have impacted on the incidence of self harm or suicide at the population level. These findings are important because they do not suggest that reduced access to SSRIs in young people has had an adverse impact on suicidal behaviour among adolescents in the UK, as has been suggested. Longer term impacts on population health of recent changes in antidepressant prescribing requires careful assessment.