5‐Hydroxytryptamine Receptor 2A encodes one of the receptors for serotonin, a neurotransmitter with many roles. Mutations in this gene are associated with susceptibility to schizophrenia and obsessive‐compulsive disorder and are also associated with response to the antidepressant citalopram in patients with major depressive disorder (MDD). Here, HTR2A is linked to major depressive disorder.