Used as an active metabolite in the treatment of depression and seasonal affective disorder, hydroxybupropion contributes to the overall antidepressant effect when bupropion is administered. It plays a key role in smoking cessation therapy by helping reduce nicotine cravings and withdrawal symptoms. Due to its action on dopamine and norepinephrine reuptake inhibition, it supports mood regulation and enhances focus and motivation in patients. Its presence in the bloodstream prolongs the therapeutic activity of the parent drug, making it important for sustained clinical response.