Prevalence and variation in antidepressant prescribing across Northern Ireland

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Evidence indicates an increase in antidepressant prescription rates across the UK however rates of depression are not changing substantially. There was a 165% increase in the prescribing of antidepressant drugs in England between 1998 and 2012 (an average of 7.2% a year). However the reasons behind these figures are not clear]. There is a strong evidence base detailing associations between socioeconomic deprivation and poor mental health.

Recent recession induced unemployment, poverty and inequality are likely to have contributed to increases in mental health difficulties, and a subsequent demand for health services. A recent Nuffield Trust and Health Foundation Quality Watch report documented trends in the prescribing of antidepressants in primary care across the UK. Longitudinal analysis demonstrated that higher unemployment was associated with significant increases in the number of anti-depressant tablets that were distributed.

A 1% rise in unemployment typically meant that one and a half more tablets were prescribed per person, per year. Notably, there were sizable geographical variations in prescription rates across the UK. During the period between October and December 2012/13, rates varied from 71 items per 1,000 people in NHS Brent, to 331 items per 1,000 people in NHS Blackpool. Generally, there were lower levels of prescribing in London, and higher rates in the North East.

GP practices that prescribed more antidepressants had a greater percentage of patients that were aged 65 and over, female and white. The quantity of antidepressants prescribed was also associated with GP practice characteristics such as the number of GPs per 10,000 patients and the number of antibiotics prescribed. Moreover, GP practices in areas with better health prescribed more antidepressants, whereas GP practices in areas with better housing prescribed fewer antidepressants.

Although there has been a recent increase in the prevalence of depression recorded by GPs, this change cannot fully account for the increased dispensing of antidepressants. In fact, research by the Mental Health Foundation found that 78% of GPs had prescribed an antidepressant in the previous three years, despite believing that an alternative treatment might have been more appropriate.

It also found that 66% had done so because a suitable alternative was not available, 62% because there was a waiting list for the suitable alternative, and 33% because the patient requested antidepressants. Of the GPs surveyed, 60% said they would prescribe antidepressants less frequently if other options were available to them.

More recently, the ‘Script Report’, based on a freedom of information request on U.K. prescribing practices, gained access to 36 million prescription records from across the UK, including 3.5 million prescriptions from GPs in NI for the period April to September 2013. The findings showed that NI prescribed proportionately more antidepressants than 23 other countries, and that NI consumed more than two-and-a-half times the antidepressants per head than in similarly wealthy economic areas in England.

Overall, GPs in NI prescribed enough antidepressants to give every member of the population a 27-day supply; the same statistics for England and Wales were 10 days and 19 days respectively. To date however no analysis has been conducted to investigate the socio-economic context of this pattern of prescribing.

In summary the aforementioned research indicates that (a) the prevalence of antidepressant prescribing can be explained by personal, social and economic factors, (b) the supply-demand association for antidepressant prescribing is moderated by personal, social and economic factors, and (c) the relative importance of these moderating factors vary geographically.

This project was supported by a research grant from the ESRC through the Secondary Data Analysis Initiative. The investigators are from Ulster University (Mark Shevlin, Jamie Murphy, Michael Rosato, & Stephanie Boyle), Huddersfield University (Daniel Boduszek), and AWARE (Tom McEneaney).

Specifically this project aimed to (i) provide a detailed breakdown of antidepressant prescribing in NI from 2011 to 2015, (ii) use linked census data to identify demographic variables that predict antidepressant prescribing, and (iii) stimulate ‘social prescribing’ across the region through targeted intervention through collaboration with Aware.

Executive Summary

Anti-depressant prescription rates in the United Kingdom (UK) are among the highest in Western Europe and prescription rates in Northern Ireland (NI) are significantly higher than the rest of the UK. Moreover, while prescription rates are climbing annually, rates of depression are not changing, and evidence suggests that a range of socio-economic and geographical factors may be responsible.

The primary aim of this project was to use data-linkage techniques trough the Administrative Data Research Centre (Northern Ireland) to link returns from the 2011 NI Census and data on anti-depressant prescribing from the Enhanced Prescribing Database to help inform the work of our non-academic partner Aware Defeat Depression (AWARE NI). Project outcomes include

Successful linkage of 92.58% of the 2011 NI Census cases with the Enhanced Prescribing Database was achieved, resulting in a sample of 1,588,491 individuals.
For years 2011 to 2015 the prevalence of anti-depressant prescribing was 12.45%, 13.08%, 13.67%, 14.23%, 14.93%, and over the 5-year period the prevalence was 24.12%.
Self-reported mental health condition (OR=3.37), poor physical health (OR=3.22), female gender (OR=2.08), disability (OR=1.34), lower rateable property value (ORs = 1.11 – 1.63) and lone parent family (OR=1.17) were all significant risk factors for anti-depressant prescribing.
Some variables were found to be protective; age 40-54 years (OR=.94), not being in a family (OR=0.95), being Catholic (OR=0.91) or No faith (OR=.95), and being a full-time (OR=0.53) or part-time student (OR=0.59).
In collaboration with AWARE NI, The project findings were presented at an End of Project Briefing Conference with representatives from the Royal College of Psychiatrists, the Public Health Agency, the Belfast Health and Social Care Trust, and academics from Ulster University and Queens University Belfast in attendance.
AWARE has used the project findings to tailor delivery of training and services.