The prefrontal cortex in drug addiction: insights from human and non-human primate neuroimaging

This paper reviews neuroimaging evidence from humans and non-human primates to examine how drug addiction impacts the prefrontal cortex (PFC). The authors utilize the impaired Response Inhibition and Salience Attribution (iRISA) framework to explain how PFC dysfunction leads to the hallmark behaviors of addiction: an inability to suppress drug-seeking (inhibitory control) and an over-valuation of drug-related cues (salience attribution).

The authors synthesize structural and functional neuroimaging data to demonstrate that addiction is not merely a subcortical reward-system disorder but a condition involving widespread PFC degradation. Key findings include:

• Structural Damage: Chronic drug use is associated with reduced gray matter volume and white matter integrity in PFC regions like the orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC).
• Functional Impairment: Addicted individuals show blunted PFC activity during non-drug tasks but hyper-reactivity to drug cues, which correlates with craving and relapse risk.
• Causality and Recovery: By comparing human data with longitudinal non-human primate studies, the authors establish that chronic drug self-administration causes PFC damage. Crucially, they find that this damage is partially reversible through sustained abstinence, suggesting potential for neuroplastic recovery.

Understanding that addiction causes tangible, yet potentially reversible, damage to the PFC shifts the clinical perspective from viewing addiction solely as a failure of willpower to recognizing it as a neurobiological disorder. This insight supports the development of targeted treatments—such as neuromodulation (e.g., TMS, tDCS) and cognitive training—aimed at restoring PFC function to improve long-term abstinence outcomes.