Psychology
Antidepressants: what they do, side effects and stopping safely
What antidepressants treat, how long they take, common side effects, whether they are addictive, and why you should never stop them suddenly.
27 Sept 20268 min read
Serotonin
Pronounced sair-uh-TOH-nin
Also known as 5-HT, 5-hydroxytryptamine, Happy hormone, Happy chemical
A chemical messenger involved in mood, sleep, appetite, digestion and much more. About 90% of the body's serotonin is in the gut. It is not simply a "happy chemical".
In Psychology
Serotonin is a with many jobs: it helps regulate mood, sleep, appetite, digestion, nausea, body temperature, blood clotting and sexual function. About 90% of it is found in the lining of the gut; only a small share is made in the brain.
The "happy chemical" myth
You will often read that is caused by low serotonin and that antidepressants "top it up". That is an oversimplification. A 2022 umbrella review found no consistent evidence that depression is caused by lowered serotonin. Depression comes from a mix of biology, genes, stress, life events and thinking patterns.
That does not make the medicines useless. , which act on serotonin, help many people — we simply understand why less well than the slogan suggests. Do not stop an antidepressant because of this debate; talk to your doctor.
Where this comes up
Related terms
- NeurotransmitterBrain chemical, Chemical messengerA chemical messenger that carries signals from one nerve cell to the next, or to a muscle or gland. Serotonin, dopamine, noradrenaline, GABA and glutamate are examples.
- SSRISelective serotonin reuptake inhibitor, SSRIsSelective serotonin reuptake inhibitor: the most commonly prescribed type of antidepressant, used for depression and many anxiety conditions. Examples are sertraline, fluoxetine, escitalopram, citalopram and paroxetine.
- DopamineDopamine hit, Dopamine detoxA chemical messenger involved in motivation, reward, learning, movement and attention. It is better thought of as a "seeking and learning" chemical than a "pleasure chemical".
- DepressionClinical depression, Major depressive disorderA medical condition in which low mood or loss of interest lasts most of the day, nearly every day, for at least two weeks, and affects sleep, energy and daily life.