Antidepressants and Dementia: Is There a Link?

Antidepressants and Dementia: Is There a Link?

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By Clare Knight, B.Sc.Reviewed by Dr. Liji Thomas, MD

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• How Do Antidepressants Work?
• Is There a Link Between Antidepressants and the Increased Risk of Dementia?
• Take-Home Message

Dementia is a neurodegenerative disorder. There is no cure for this chronic and progressive condition, which impairs memory as well as judgment in function, in behaviour and language. A large amount of research into dementia is focused on the prevention of this condition rather than its cure. This article examines the link between antidepressants and the development of dementia.

How Do Antidepressants Work?

Antidepressants are used to help patients suffering from depression. Many different types of antidepressants have been developed. They are very similar in their mode of action; however, they differ in structure as well as in their adverse effects. Selective serotonin reuptake inhibitors (SSRIs) are one type of antidepressants. They block the reuptake of serotonin into the nerve cell and prolong its action within the brain. Serotonin and noradrenalin reuptake inhibitors (SNRIs) also inhibit the reuptake of serotonin but also that of noradrenalin, increasing the levels of both neurotransmitters over a longer duration in the brain. Another drug category is known as monoamine oxidase inhibitors (MAOIs); they also increase the duration of neuronal activation by serotonin and noradrenalin by making it harder for monoamine oxidase to break them down.

Antidepressants may affect the risk of dementia by their different mechanisms of action, which may include anticholinergic characteristics, cytotoxicity in many normal cells, neuron growth and death, some neurologic adverse effects and other symptoms.