Antidepressant Use at the Threshold: using electronic health records to characterise people prescribed antidepressants around the time of dementia diagnosis

Antidepressant use is common in people with dementia. Antidepressants may be started to manage symptoms of dementia, rather than depressive and anxiety disorders. We hypothesised people prescribed antidepressants around the time of dementia diagnosis may have different characteristics from those with longstanding prescriptions. We used linked primary care (Lambeth DataNet) and specialist (Clinical Record Interactive Search) data for patients with dementia in south London, UK. Antidepressant prescription was ascertained, and a new start was within one year before or after dementia diagnosis. Coded fields, a rating scale for neuropsychiatric symptoms and natural language processing of full-text were used to describe depression and anxiety. Of 3,713 patients with dementia, 28% were prescribed antidepressants within the year of dementia diagnosis, and 42% of these were new start prescriptions. Compared to the no antidepressant group, the new start group were more likely to be female, have vascular dementia and neuropsychiatric symptoms. Compared to the long-standing group, new start had fewer comorbidities; people from non-White ethnicities were more likely to lack documentation of depression or anxiety. Deprescribing was equally unlikely in new and long-term prescriptions (6.3% vs 5.5% per year of follow-up). The high incidence of new prescribing, as well as the lack of deprescribing, points to unmet needs and a role for more proactive medication review. Further studies should include the clinician and patient voices to further understand how to improve non-pharmacological support for people at the threshold of dementia.