The findings of a systematic review published in BMJ Open support anxiety as a modifiable risk factor for later dementia, as opposed to a prodromal feature of neurodegeneration.
With few treatment options available for dementia, clinicians are particularly interested in its prevention. It has been well established that depression, which commonly co-occurs with anxiety, is associated with the development of dementia. However, fewer studies have examined the role of anxiety alone.
Prospective cohort and case-controlled studies were eligible for the review if they included standardized clinical assessments of both anxiety and dementia, with late-onset dementia diagnosis (≥65 years) and anxiety assessed at least 10 years prior to a final dementia diagnosis. Studies that did not control for depression or that focused on populations with posttraumatic stress disorder or obsessive-compulsive disorder were excluded.
Of the 3510 articles yielded by Medline, PsycINFO, and Embase, 4 met these criteria, with a total sample size of 29,819. Authors verified the quality of eligible studies on the Newcastle-Ottawa Scale.
All 4 studies reported a significant association between midlife anxiety and late-onset dementia diagnosis, with anxiety occurring, on average, at least 10 years before a dementia diagnosis. Although anxiety has been thought of as a prodromal feature of cognitive decline, its relatively early appearance in these studies suggests that it could also be a risk factor.
Heterogeneous design and a limited number of eligible studies prevented formal statistical analyses. The authors also stated that, ideally, retrospective studies would include assessments of cognitive functioning at baseline, but the predetermined exclusion criteria for the review were already rigorous.
In treating midlife anxiety, the authors encouraged clinicians not to rely solely on medication, as benzodiazepines have been shown to increase mortality in certain groups. They pointed to talk therapy, meditation, and mindfulness-based interventions as possible considerations. Whether this treatment is preventive of later dementia, however, will require further research.
Gimson A, Schlosser M, Huntley JD, Marchant NL. Support for midlife anxiety diagnosis as an independent risk factor for dementia: a systematic review. BMJ Open. 2018;8:e019399.