May 14 / Simcha

How Antidepressants Work: A New Explanation

The following selection from a recent Elle Magazine article about the use of antidepressants to improve couple relations (The Couple Who Medicates Together by Louisa Kamps 4.18.12,) offers an interesting look at how anti-depressants work.


Many of us believe that SSRIs work by correcting a simple serotonin deficiency in the brain, but scientists who study depression now mostly consider that to be “last-century thinking,” as one Harvard neuroscientist put it. The new view of how depression develops, and how antidepressants work to relieve it, revolves around stress — wear and tear, that is, in parts of the brain that regulate emotions.

“What we and others have found is that chronic stress can decrease the levels of neurotrophic, or growth, factors in the brain,” says Ronald S. Duman, a professor of psychiatry and pharmacology at Yale University and a leading scientist in the field. Mental illness occurs, the theory goes, when stress mechanisms are on overdrive, causing the atrophy of neurons in such areas as the hippocampus (the region controlling mood and emotion) and the prefrontal cortex (the seat of executive thinking). “It’s very clear,” Duman says, “that antidepressants increase neurogenesis, helping the brain recover.”

No one knows exactly why the combination of antidepressants plus therapy — specifically CBT but also some types of couples therapy — helps many people recover from depression and prevents relapse better than either treatment alone, as studies have consistently shown. Psychologist Zindel Segal’s supposition is that antidepressants allow therapy’s messages to sink in “by regulating emotions, creating a buffer between you and what you’re feeling.” When your brain “is hijacked by strong emotional reactions, the cognitive learning centers shut down,” says Segal, a professor at the University of Toronto.

And evidence is building that long-lasting recovery from depression requires actually learning to behave in some new way, with brain and body fully engaged, so that harmful, ingrained thoughts are overridden by healthier ones.

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Experts also stress that antidepressants are not the only, or even the best, way to make marriage sunnier for people with mild depression. Exercise has been well established to lift mood. Increasing dietary intake of high-purity Omega 3 fatty acid to 1–2 grams per day reduces depressive symptoms, studies have found. A program known as Mindfulness-Based Cognitive Therapy (MBCT), which combines elements of CBT with mindfulness meditation, curtails anxiety and prevents relapse of major depression on par with antidepressants, Segal’s research has shown. And, yes, good couples therapy can also help people understand better the contours — weak but possibly stronger than they think — of their relationships.