The authors of a study published in Alzheimer Disease and Associated Disorders found that elderly individuals using antidepressants were at significantly higher risk for dementia when compared with both depressed and not depressed nonusers. The study, which is one of the few long-term studies focusing on associations between antidepressants and dementia, followed a large group of participants for up to 18 years.
“In this elderly primary care patient cohort, we found that SSRIs users were at significantly higher risk for incident dementia when compared with not depressed nonusers and also when compared with nonusers with depression. Patients who were taking non-SSRIs also showed significantly higher risk for incident dementia when compared with nonusers without depression.”
Antidepressants, including selective serotonin re-uptake inhibitors (SSRI), are commonly prescribed drugs in the U.S. Despite studies that have suggested these could have neuroprotective effects and that they can improve cognitive function in patients with Alzheimer’s dementia, these results are not consistent. Studies conducted with different populations have also found conflicting results with some finding that older antidepressants were associated with a reduced rate of dementia and others have found antidepressant use associated with cognitive impairment. Further, as the authors, led by Dr. Chenkun Wang, point out, elderly individuals are often underrepresented in clinical trials, therefore little is known about this antidepressant use in this population, particularly those with unimpaired cognitive functioning.
Over a span of two years (i.e. 1991-1993) 3,688 patients from a private care practice were enrolled in the study and included in the analysis – all of whom were 60 years of age or older. The researchers used medical history information from inpatient, outpatient, and emergency room records. Among the data retrieved were diagnoses of depression and dementia. Data regarding their antidepressant medication prescription and dispersal was also retrieved from their electronic medical record. Patients were divided into 5 groups:
- Prescribed only SSRIs
- Prescribed only non-SSRIs anti-depressants
- Prescribed mixed anti-depressants (non-SSRIs & SSRIs)
- Participants diagnosed with depression but not prescribed antidepressants (nonusers with depression)
- Participants diagnosed who were not diagnosed with depression nor received antidepressants (nonusers without depression)
Results revealed that participants who were on SSRIs or non-SSRI antidepressants had a higher risk of dementia than the individuals diagnosed with depression who were not prescribed antidepressants. In addition, those who were on either type of antidepressant were at a higher risk of dementia than nonusers without depression.
Despite the limitations of the study, which include prescribing bias (e.g. doctors prescribing SSRIs to adults with cognitive impairments) and lack of depression and dementia severity measures, this is not the only study to yield these associations. A recent article on Medscape reporting on SSRIs and sleep disruption found that these antidepressants could cause significant sleep problems in the elderly, which could contribute to neurodegeneration leading to dementia. The authors of the study, which was presented at the Institute of Psychiatric Services: The Mental Health Services 2016 Conference, warn against ignoring sleep issues and side-effects of SSRIs and reiterate the importance of psychotherapy and holistic alternatives for elderly populations.
Wang, C., Gao, S., Hendrie, H. C., Kesterson, J., Campbell, N. L., Shekhar, A., & Callahan, C. M. (2016). Antidepressant use in the elderly is associated with an increased risk of dementia. Alzheimer Disease & Associated Disorders, 30(2), 99-104. (Abstract)