A gene-by-environment interaction involving the 5-HTTLPR gene may contribute to this disorder. Max Hamilton developed a popular 17-question rating scale for this condition. Aaron Beck claimed that this disorder was characterized by a cognitive triad involving one's thoughts about oneself, one's future, and the world. One hypothesis for this disorder's etiology is hyperactivity of monoamine oxidase A. (*) Tricyclic drugs used for this condition include imipramine. A chronic, less severe form of this disorder is dysthymia. Bipolar disorder involves swings between symptoms of this disorder and mania. Selective serotonin 
A gene-by-environment interaction involving the 5-HTTLPR gene may contribute to this disorder. Max Hamilton developed a popular 17-question rating scale for this condition. Aaron Beck claimed that this disorder was characterized by a cognitive triad involving one's thoughts about oneself, one's future, and the world. One hypothesis for this disorder's etiology is hyperactivity of monoamine oxidase A. (*) Tricyclic drugs used for this condition include imipramine. A chronic, less severe form of this disorder is dysthymia. Bipolar disorder involves swings between symptoms of this disorder and mania. Selective serotonin reuptake inhibitors like Zoloft are primarily used to treat this disorder. For 10 points, name this mood disorder characterized by loss of interest in normal activities and persistent low mood.
A gene-by-environment interaction involving the 5-HTTLPR gene may contribute to this disorder.
major depression [or major depressive disorder; or MDD; or clinical depression]