Tricyclic antidepressants are a type of medication chiefly used to treat clinical depression. However, they may also be used to treat other conditions such as obsessive-compulsive disorder (OCD), bedwetting (enuresis) and some chronic pain conditions.

From the 1960s to the 1980s, tricyclic antidepressants were the first choice of medications used to treat depression. However, they can have significant side effects such as cardiac arrhythmias (irregular heartbeats)  and may cause life-threatening consequences including hallucinations, seizures and coma, when taken in high dosage levels. As a result, many physicians prescribe alternative antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), that are less likely to trigger such undesirable effects. Today, tricyclics are most often used in individuals who have failed to respond to other types of antidepressants.