L-methylfolate, the active form of folic acid, is required to synthesize neurotransmitters such as serotonin, dopamine, and norepinephrine.

Valproic acid (VPA) is the go-to antimanic agent for acute manic episodes, featuring faster onset of response and a better adverse effect profile compared to lithium, fewer drug interactions than carbamazepine, and efficacy for rapid cycling and relapse prevention.

Cariprazine is a partial dopamine agonist similar to aripiprazole and brexpiprazole.

Brexpiprazole is a partial dopamine agonist closely related to aripiprazole, with similar efficacy.

Vilazodone is essentially an SSRI with added buspirone-like 5-HT1A partial agonist effects.

Venlafaxine may be slightly more effective than SSRIs, but side effects—especially blood pressure elevation and withdrawal symptoms—make it a second-line option.

TCAs are less commonly used today due to side effects and overdose risk but remain a valid option for patients who haven’t responded to other antidepressants.

Trazodone is most often prescribed at low doses (25–50 mg) as a sleep aid.