Which TCA is used to treat both depression and nighttime bed-wetting?

Imipramine is the correct answer because it is a tricyclic antidepressant (TCA) that has been shown to be effective in treating both major depressive disorder and enuresis, commonly referred to as nighttime bed-wetting in children. Imipramine's effectiveness in this area is attributed to its ability to inhibit the reuptake of norepinephrine and serotonin, which can help regulate mood and also influence the bladder's function.

Specifically, when used for enuresis, it is believed that imipramine acts on the central nervous system to increase bladder capacity and decrease the frequency of bed-wetting episodes. This dual action makes imipramine unique among TCAs, as most are primarily used for depressive disorders without FDA approval for enuresis.

While clomipramine is a TCA that is primarily utilized for obsessive-compulsive disorder and also has some effect on enuresis, imipramine is more commonly recognized and studied for its effectiveness specifically in both conditions. Doxepin and protriptyline are other TCAs, but they are primarily focused on depression and do not have the same established efficacy for treating bed-wetting.