Sunday, June 25, 2023
Alexander Papp
The serotonin theory of depression has been around for a good 60 years and is often used as justification for the use of antidepressants, specifically selective serotonin re-uptake inhibitors (SSRIs).
Understandably, a review published recently by psychiatric researcher Joanna Moncrieff, which concluded that there was no consistent evidence of an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations, created quite a stir.
The researchers suggested that many people believe depression is caused by “low serotonin” or a “chemical imbalance”, and that antidepressants don’t work by targeting these unproven abnormalities. This study was picked up by the national media, sparking fears among patients that depression has been overmedicalized.
While there is indeed limited evidence regarding the efficacy of long-term antidepressant use, there is strong evidence that antidepressants can help relieve the symptoms of chronic depression for many individuals, and lead to significantly lower rates of relapse, or recurrence.
Other researcjers have pointed out that the possible role of serotonin in depression was a separate question from the antidepressant effects of SSRIs. It is well known that antidepressants affect several pathways and receptors in the brain, not just serotonin.
Moncrieff’s study does not conclude that antidepressants do not work, and patients should not stop taking their antidepressants suddenly. Antidepressants remain “a lifeline” for many patients prescribed them.
It was never an actual scientific theory that depression is caused by some imbalance in brain chemistry – it was always a popular oversimplification of a very complex problem.
Scientists continue working to understand the mechanisms causing depression, but what is already clear that it is a heterogenous disorder with many underlying causes. Depression results from a complex interaction of social, psychological and biological factors, and may be influenced by existing mental health conditions. It can be linked with childhood experiences, stressful life events, personality traits, family history, recreational drug and alcohol use, physical health problems and genetics. People with existing other mental health conditions, such as an eating disorder or post-traumatic stress disorder, may also be more likely to experience depression.
These factors are why a combination of antidepressants and talking therapies is often recommended as the best approach to treating depression.
