You’ve probably heard about the chemical imbalance theory of depression. It states that depression is caused by low levels of the neurotransmitter serotonin, also known as 5-HT, in the brain. There is.
The theory originates from the 1960s, when doctors used medications such as Iproniazid mood enhancers, which they believed worked by increasing serotonin concentrations in the brain.
Since then, the idea stuck as a simple explanation for depression, and one with an attractively simple treatment: taking SSRIs (selective serotonin reuptake inhibitors) such as Prozac to boost serotonin levels.
Experts have known for a long time that this theory is an oversimplification.
Serotonin not involved in depression
Now, a goes even further, concluding that there is “no clear evidence” that low serotonin levels cause depression.
The study, which gathered evidence from 361 peer-reviewed scientific studies, found no link between depression and serotonin levels in the blood. Similarly, the researchers behind it found no differences in serotonin receptors or transporters in the brains of people with depression compared to brains of people without depression.
“Depression has lots of different symptoms, and I don’t think I’ve met any serious scientists or psychiatrists who think that all causes of depression are caused by a simple chemical imbalance in serotonin,” said Michael Bloomfield, consultant psychiatrist and researcher at University College London, who was not involved in the study. Although experts weren’t surprised by the fact that low levels of serotonin can cause depression, most people disagree with this conclusion.
” It is possible that certain people suffering from depression may have symptoms related to changes in their serotonin levels. Bloomfield stated. “The problem with this review is that it has lumped together depression as if it is a single disorder, which, from a biological perspective, does not make any sense.”
Antidepressants not so effective at treating depression?
The study goes on to suggest that SSRI antidepressants such as Prozac, which work by blocking serotonin reuptake in the brain, should not be used to treat depression.
The study points to research that found that antidepressants are , particularly in those with moderate or less-severe depression. The authors suggest that belief in the chemical imbalance theory may discourage people from stopping treatment, potentially leading to lifelong dependence on these drugs.
David Curtis is an honorary professor at UCL Genetics Institute, UK. He challenged the conclusion and said that it was important for people suffering from severe depression to receive appropriate treatment. Curtis stated that it is clear that depressive illnesses can cause brain dysfunctionalities. Although we don’t know the exact causes, antidepressants have proven to be effective in treating severe cases.
What is the cause of depression?
If, as the new study claims, serotonin isn’t linked with depression, what causes it? Experts say that depression can be caused by multiple factors. The meta-study does not offer any alternative explanation.
Unsurprisingly, negative life events, and how we deal with them, have a huge impact on depression. It is well-known that stress can trigger depression.
“Depression can be triggered by life events,” Patricia Fonseca (psychiatrician at the Max-Planck-Insitut for Psychiatry, Munich, Germany) told DW. But it is important to note that genetic influences can also play a role in the onset of depression. By having a special genetic predisposition, distressing life events can trigger the onset of depression.”
Current theories have moved on from explanations of single neurotransmitters such as serotonin. Instead, they focus on how depression changes complex networks in the brain that process emotions and stress.
Theories involve key roles of regions in the brain such as the amygdala and prefrontal cortex. Emotions are processed in the amygdala, which are then assessed for meaning in the prefrontal cortex. People with depression tend to have a reduced volume of the amygdala, as well as reduced connectivity between it and the cortex.
Experts suggest that depression is caused by the cortex more negatively appraising emotions, particularly those triggered by events linked with bad memories.
Chronic Stress can also have an impact on these networks and affect the brain’s ability adapt to stress situations. In turn, this causes preexisting vulnerabilities to manifest.
New ways to treat depression look more effective
With the mixed effectiveness of antidepressants, scientists have been keen to identify new ways to treat depression.
There is increasing evidence for the benefits of mind-altering drugs such as ketamine and psilocybin mushrooms in treating depression. found that psilocybin was more effective than the antidepressant drug escitalopram.
Brain-imaging studies have found that these drugs help increase connectivity in the brain. The thinking is that the substances help people to reprocess old emotions in a new light, while also rewiring the brain to reduce depressive tendencies.
Fonseca also emphasized the effectiveness of nonpharmacological treatments in treating depression. Fonseca stated that depression prevention must be emphasized with skills such as mindfulness, acceptance, and reduction of stress. “This might include psychotherapy, where people aim to handle stress and depression much better.”
In therapy, Fonseca said, people have time to find out triggers of depression. You can find out about your disease so that you are able to deal with life’s challenges.
Edited by: Carla Bleiker
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