Vilazodone hydrochloride is primarily used as an antidepressant in the treatment of major depressive disorder (MDD). It functions as a selective serotonin reuptake inhibitor (SSRI) and a partial agonist of the 5-HT1A receptor, which helps enhance serotonin activity in the brain. This dual mechanism is believed to improve mood, reduce anxiety, and alleviate symptoms of depression more effectively than traditional SSRIs alone. It is typically prescribed for adults and is taken orally once daily, often with food to improve absorption. Patients may experience symptom improvement within a few weeks, though full benefits may take longer. Common side effects include nausea, diarrhea, and insomnia, but it is generally well-tolerated. It is important to follow medical guidance when using this medication, as abrupt discontinuation can lead to withdrawal symptoms.