A brief overview of our current understanding of the neurobiological processes that underlie addiction.
PDF Version Plus Figures
It is only recently that the idea that addiction is a brain disease has begun to be accepted by the general population. The disease model was at the centre of the AA/NA message long before it became accepted by even the medical field. As we make advances in neuroscience we are finding that many of the conclusions drawn from anecdotal evidence have, in fact, a sound neurobiological basis. There is indeed a strong neurological underpinning for addiction, and in this essay I will summarise the current understanding of this.
What is Addiction?
The American Psychiatric Association defines addiction as a "chronically relapsing disorder that is characterized by three major elements: (a) compulsion to seek and take the drug, (b) loss of control in limiting intake, and (c) emergence of a negative emotional state when access to the drug is prevented". The American Society of Addiction Medicine have much more extensive short and long definitions of addiction which encompass these three concepts. This moves us away from the DSM-IV concept of abuse and dependence, which focus on issues of tolerance and withdrawal. It has been demonstrated that dependence can develop without the criteria for addiction being met, for example in the case of Beta-blockers.
Addiction is not simply substance use or abuse. It is, in my opinion, a pathological “relationship” with the substance or activity at the expense of more appropriate or beneficial relationships.
It is this state of addiction, after chronic drug use that results in changes in the brain and manifests in the behavioural patterns described in the definition, above that is covered in this essay.