Antidepressants and Risk of Dementia: Methodology Is Essential

See reply by Kao and article by Lee et al

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Antidepressants and Risk of Dementia: Methodology Is Essential

To the Editor: Having read with great interest the recent JCP article by Lee et al1 that examined the association between antidepressant treatment and risk of dementia, I would like to make some remarks on this important topic.

First, in relation to patient selection, the first group that was selected from the Catastrophic Illnesses Patient Database (of the Taiwan National Health Insurance Research Database) was treated for depression in 1997-2004 and newly diagnosed with dementia in 2005-2011. The control group was not selected from the same database and did not have a catastrophic illness certificate. However, they were newly diagnosed with major depression in 2005-2011 and did not have dementia. This comparison of the 2 groups is not suitable and leads to bias. The use of antidepressants would be expected more in the first group than in the second group. The control group should also have been selected from the Catastrophic Illnesses Patient Database (from those without a diagnosis of dementia).

Second, regarding the cumulative antidepressant dose, antidepressant dose ranges even in the same class differ from each other. For example, one selective serotonin reuptake inhibitor (SSRI), fluvoxamine, has a 50-300 mg/d dose range, while another SSRI, escitalopram, has a dose range of 10-20 mg/d. Calculating the cumulative dose of each drug separately (sertraline, paroxetine…) rather than as a group (SSRI, TCAs…) would be more appropriate.

Because of these two methodological limitations, it would not be absolutely right to claim that antidepressant use is associated with a (reduced or increased) risk of dementia on the basis of this study.

Reference

1. Lee CW, Lin CL, Sung FC, et al. Antidepressant treatment and risk of dementia: a population-based, retrospective case-control study. J Clin Psychiatry. 2016;77(1):117-122. PubMed doi:10.4088/JCP.14m09580

Ali Doruk, MDa

dralidoruk@yahoo.com

aGulhane Medical Faculty, Psychiatry, GATA Psikiyatri, Etlik, Ankara, Turkey

Potential conflicts of interest: None.

Funding/support: None.

J Clin Psychiatry 2016;77(9):e1151

dx.doi.org/10.4088/JCP.16lr10742

© Copyright 2016 Physicians Postgraduate Press, Inc.