With the tantalizing title, Drug Addiction: Neurobiology of Disrupted Free Will, Volkow tackles head-on one of the central paradoxes of addiction, namely that addiction is a behavior, hence theoretically subject to our free will, and yet it is a behavior which we feel compelled to choose even when we take no pleasure in it and do not want to do it.
Volkow's video lecture runs just over one hour, and if you have any intellectual curiosity about this issue you owe it to yourself to take the time and view it in its entirety. During the first 45 minutes, Volkow reviews territory that will feel familiar to anyone who paid attention to brain research during the 1990s, namely the interplay between addiction and certain receptors for dopamine, notably the low number of D2 receptors in the brains of addicted persons-- processes that occur mainly in the limbic system of the mid-brain. The gist of this is that addicted persons have a reduced anatomical ability to take pleasure from substances that normally provide it.
Then at about minute 48, she launches into the cutting-edge new stuff: research that shows the unmistakable footprint of addiction in the so-called "higher" brain, the forebrain structures where we do our abstract reasoning. The anterior cingulate cortex has the role of interpreting the meaning of external stimuli; it is the spin doctor. In persons who are addicted, this structure is damaged; it has lost its plasticity and can no longer play its normal role of inhibiting urges coming from the limbic system. What emerges from Volkow's lecture is a much more complex, nuanced, and interesting picture of the addicted brain than could have been constructed on the basis of research done ten years ago.
Among the notable points that remained with me:
- Central to the definition of addiction, in Volkow's view, is the fact that addicted persons both want and do not want to use the drug. Volkow is the first prominent researcher to my knowledge to grasp the fact, well known to numerous clinical workers and to addicts themselves, that addicts are internally conflicted about their addiction. The popular notion that addicts are "in denial" about their addiction (that they only want to use and do not also have a conscious contrary volition) is at best a half-truth. Volkow shows with imaging studies why the internal conflict so characteristic of addiction exists.
- Important in overcoming addiction, Volkow says (very briefly) is reinforcement of the addict's own internal inhibitory processes. In other words, positive reinforcement of the addict's inner sober strivings (what LifeRing calls "empowerment of the sober self") is conceptualized as a physiologically grounded recovery strategy.
The reality is still more complex. Although current imaging technology may not show it, in addicted persons, the limbic system supplies not only a drive to use the substance, but also a paradoxical drive to get free of it -- a "gut" urge to stop using. And the forebrain is not only a voice for abstinence, but also a paradoxical channel for voices from the culture that promote use of the addictive substance, and an engine of rationalization for addictive use. Consequently, a recovery strategy based only on enhancement of cognitive forebrain functions is likely to (a) also enhance pro-addictive forebrain processes along with anti-addictive ones, and (b) likely to overlook (and perhaps counteract) powerful anti-addictive energies emerging from the limbic system. Effective recovery, in other words, must utilize and coordinate anti-addictive potentials in both the lower and the upper brain; it must be a whole-brain strategy.
Regrettably missing from Volkow's presentation is any reference to the role of the recently discovered "mirror neurons" in shaping social behaviors. It is also worth asking whether Volkow's eminence in brain imaging -- she is one of the world's leading experts in the field -- may not inhibit the search for relevant neurochemicals and processes in other areas of the body, e.g. the stomach. But she only had an hour. These cavils aside, if you want to see a great teacher at work, relaying the state of the art to a medical audience, take an hour and watch the video, here. You will need the widely-available RealPlayer plug-in to view it on your computer, and of course your computer must be able to play sound.