Addiction, compulsive drug seeking, and the role of frontostriatal mechanisms in regulating inhibitory control.

A principal feature of drug addiction is a reduced ability to regulate control over the desire to procure drugs regardless of the risks involved. Traditional models implicated the neural 'reward' system in providing a neurobiological model of addiction. Newer models however, have expanded on this circuitry to include two separate, but interconnecting systems, the limbic system in the incentive sensitization of drugs, and the prefrontal cortex (PFC) in regulating inhibitory control over drug use. Until the recent developments in neuroimaging and brain stimulation techniques, it has been extremely difficult to assess the involvement of the PFC in addiction. In the current review, we explore the involvement of the frontostriatal circuitry in regulating inhibitory control, and suggest how dysregulation of these circuits could be involved in an increased difficulty in ceasing drug use. Following this, we investigate the recent neuropsychological, neuroimaging and brain stimulation studies that explore the presence of these inhibitory deficits, and frontostriatal dysfunctions, across various different substance groups. Further insight into these deficits could contribute to the development of treatment strategies which target these cognitive impairments, and frontostriatal dysfunction, in reducing drug-seeking behaviors.