Killing two birds with one stone: the potential role of aripiprazole for patients with comorbid major depressive disorder and nicotine dependence via altering brain activity in the anterior cingulate cortex.

The high comorbidity between major depressive disorder (MDD) and nicotine dependence (ND) is well recognized. Patients with comorbid MDD and ND often have increased suicidal risk and poor outcomes. A dysfunctional dopaminergic brain reward system might be a neurobiological link between MDD and ND. Aripiprazole has been considered as a dopamine stabilizer and was the first atypical antipsychotic agent approved by the US Food and Drug Administration as an adjunctive to the treatment of unipolar MDD. Bupropion is well known as a dual norepinephrine and dopamine reuptake inhibitor, and has been shown to be effective in smoking cessation. One reason bupropion is useful in treating ND is that it enhances the level of dopamine in the brain. Aripiprazole might act as a dopamine agonist similar to the way that bupropion does because of its partial dopamine D2 agonist and 30% intrinsic dopaminergic activity. Several recent studies have applied the unique pharmacodynamic characteristics of aripiprazole to treat patients with ND. Based on neuroimaging findings, aripiprazole can reduce substance cravings by altering brain activity, particularly in the brain regions of the anterior cingulate cortex. Therefore, we hypothesize that adjunctive aripiprazole with antidepressant may be an effective treatment for patients with MDD and ND comorbidity. A new drug invention that combines an antidepressant with an adequate dose of aripiprazole thus should be considered. The neurobiological basis for this combination to treat patients with MDD and ND comorbidity deserves further study.