Approved research

Antidepressant use and risk of morbidity and mortality: a population-based cohort study

Lay summary

Antidepressant prescribing has risen dramatically over the past decade, mainly because patients are being prescribed these drugs for a longer period. Some patients may end up taking these drugs for longer than they would like because of concerns that the depression may recur if they stop, and because of concerns relating to withdrawal symptoms. Many patients (nearly half according to a Scottish study) are staying on these drugs for more than two years. Given the rise in longer treatment, it is important to find out whether there are any negative health effects associated with taking these drugs so that doctors and patients can discuss these when making prescribing decisions. The public health impact of this work is high given the increasing number of antidepressants prescribed in England (61 million prescriptions in 2015) and the lack of research on long-term safety. Some of the common symptoms reported by patients suggest that these drugs may affect the cardiovascular system, liver and brain. Recently, two large studies, using data gathered from GP practices (covering 11 to 12 million patients) have shown that antidepressants increase the risk of conditions such as epilepsy, fractures and dementia. Many patients who start antidepressants are already at risk of developing these conditions. We want to find out the extent to which taking an antidepressant adds to this risk. To assess the size of this risk more accurately, we need to take into account a person's risk for this disease or condition before they started taking antidepressants. To do this, we need detailed information on key risk factors for all the diseases and conditions of interest. Unfortunately, previous studies have been unable to take these risk factors into account because this information is not measured and recorded for everyone in primary care. We plan to use data collected by UK Biobank, a large study that recruited just over 500,000 participants from across the UK between 2006 to 2010. This study is an ideal resource to explore the long-term effects of antidepressants because it has extensive information on a range of risk factors for disease and it is also linked to GP and hospital records allowing us to look at the effect of antidepressants on a wide range of conditions and diseases.