Overview
Antidepressants are a class of medications that target the production of monoamine neurotransmitters like serotonin, norepinephrine, and dopamine which are thought to be associated with depression and anxiety.
The old biological theory of depression posits that an imbalance between these is responsible for depression, and this is still the narrative commonly found in the public consciousness thanks to pharmaceutical marketing campaigns, but the consensus in research circles is that reality is more complex. Consider that if you take aspirin to address a headache, we wouldn’t necessarily say you had an aspirin-deficiency. Yet, this was the assumption made by researchers and clinicians upon observing that providing patients with drugs that boosted their serotonin levels also improved their symptoms of depression. In 2022, a study led by Joanna Moncrieff at University College London analyzed decades of data and found no consistent evidence that low serotonin levels were the cause of depression.
Instead, modern research is interested in neuroplasticity and neurogenesis as explanations. The inflammation and floods of cortisol from chronic stress is thought to drop a protein called Brain-Derived Neurotrophic Factor (BDNF) which stimulates the repair and rebuilding of neural pathway. Antidepressants might work by increasing the activity of BDNF over the course of weeks or months; this means that they can increase neuroplasticty, but not that they automatically provide feelings of happiness without a psychosocial framework that takes advantage of the brain’s capacity to change.