Adult Hippocampal Neurogenesis in the Pathogenesis of Addiction and Dual Diagnosis Disorders

Abstract

Background: As knowledge deepens about how new neurons are born, differentiate, and wire into the adult mammalian brain, growing evidence depicts hippocampal neurogenesis as a special form of neuroplasticity that may be impaired across psychiatric disorders. This review provides an integrated-evidence based framework describing a neurogenic basis for addictions and addiction vulnerability in mental illness. Methods: Basic studies conducted over the last decade examining the effects of addictive drugs on adult neurogenesis and the impact of neurogenic activity on addictive behavior were compiled and integrated with relevant neurocomputational and human studies. Results: While suppression of hippocampal neurogenic proliferation appears to be a universal property of addictive drugs, the pathophysiology of addictions involves neuroadaptative processes within frontal-cortical-striatal motivation circuits that the neurogenic hippocampus regulates via direct projections. States of suppressed neurogenic activity may simultaneously underlie psychiatric and cognitive symptoms, but also confer or signify hippocampal dysfunction that heightens addiction vulnerability in mental illness as a basis for dual diagnosis disorders. Conclusions: Research on pharmacological, behavioral and experiential strategies that enhance adaptive regulation of hippocampal neurogenesis holds potential in advancing preventative and integrative treatment strategies for addictions and dual diagnosis disorders.