Oct :
1950s–1960s: Researchers observed that drugs affecting serotonin, norepinephrine, and dopamine could improve symptoms in some patients. This led to the monoamine hypothesis, proposing that deficiencies in these neurotransmitters might cause depression.
1970s–1990s: Despite growing public messaging that depression was due to a “chemical imbalance,” researchers increasingly acknowledged that direct evidence for this explanation was weak. Textbooks and scientific reviews described it as a hypothesis rather than a proven mechanism.
2000s: Advances in brain imaging, genetics, and neurobiology showed depression is far more complex. Studies failed to consistently find lower serotonin levels, fewer serotonin receptors, or other simple biochemical deficiencies in people with depression.
2010s: Many leading psychiatrists and neuroscientists publicly stated that the chemical imbalance explanation was an oversimplification. The field shifted toward models involving genetics, stress, neuroplasticity, inflammation, endocrine function, neural circuitry, and environmental factors.
2022: A major umbrella review led by Joanna Moncrieff, published in Molecular Psychiatry, concluded there was no convincing evidence that depression is caused by low serotonin or a serotonin deficiency. While the review was widely discussed, many experts noted that this reflected what much of the scientific community had already believed for years rather than overturning established science.
2026-07-10 13:04:22