An intravenous drug user gets ready to injects heroin into his arm with a needle in Vancouver's downtown Eastside January 28, 2009. John Lehmann/Globe and Mail Marc Lewis himself was a drug addict through most of his 20s – something he wrote about in his earlier book Memoirs of an Addicted Brain.JOHN LEHMANN/The Globe and Mail
What, exactly, is addiction? The scientific community – including medical doctors, psychiatrists and social workers – has a very clear answer: It's a disease, and we should approach it no differently from the way we approach heart disease or cancer. The American Society of Addiction Medicine makes it explicit in the definition it provides on its website: "Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry."
Marc Lewis, a neuroscientist and also a former addict, begs to differ. Addiction is not a disease, and declaring it to be one can get in the way of treatment, he argues. But that doesn't mean addiction is a "choice" – not exactly. If our view of addiction came down to such a simple dichotomy, the decision to label it one way or another would split cleanly on political lines: Conservatives could say that addiction is nobody's fault but the addict's, and leave them to their misery, while liberals could say it's a societal failing – and call for more public spending on research and treatment programs. (I recently heard an addiction expert on CBC Radio who was incapable of using the phrase "opiate addiction" without prefacing it with the words "the disease of." There was a good deal of politics encoded in those five words, I suspect.)
But Lewis's book isn't political, it's personal. Lewis, who taught at the University of Toronto for more than 20 years, has interviewed countless current and former addicts, and five of their stories are detailed at length in The Biology of Desire. Their struggles – with alcohol, heroin, meth, prescription pain killers, and food – are relayed with unblinking clarity, and with compassion. (Lewis himself was a drug addict through most of his 20s – something he wrote about in his earlier book Memoirs of an Addicted Brain.) Along with detailing those personal battles, Lewis examines what various substances do to our brains – and what this does and doesn't say about addiction.
The disease label took hold because neuroscientists have been able to show that drugs physically alter the brain in very specific ways. Lewis doesn't deny that; those changes are very real – but he points out that the brain is always changing, all the time. Instead, he focuses on behaviour, and the mechanisms that control it. That means taking a close look at the workings of desire. Lewis reminds us that it's normal to desire things – a good job, or the well-being of our children, for example. Problems arise only when the mechanisms that keep those desires in check begin to fail us; when our entire world begins to revolve solely around the object of that desire. We become consumed by the quest for the next "hit."
What causes those control mechanisms to fail? The reasons are complex, but Lewis argues that the drugs themselves cannot shoulder all of the blame. The biology of behaviour plays a crucial role: We engage in "motivated repetition" – the repetition of some pleasurable act – and our neural pathways change in response. We succumb to "synaptic patterns that reinforce themselves over countless repeated occasions – a creeping vine that eventually strangles the flowers in the garden."
Addicts don't need to be educated about the risks of overusing whatever substance they're hooked on; they're all too aware of the dangers. But they're focused on the immediate, on the present – the needle, the booze, the pills. This brings Lewis to what I found to be the most interesting part of his argument – the role of the imagination, and of time. (Full disclosure: I wrote a book about time back in 2008.) One thing that helps an addict quit – and in fact the majority do eventually quit, he points out – is the ability to imagine a different future, a better future. But some people, because of an impairment of certain brain regions, can't pull off this cognitive feat. For such people, the present is everything; there is no hope for a tomorrow that is any different from today.
Emerging from this temporal prison is not easy – but the addict can be (and often is) helped by outside forces. Families, supportive friends, caring communities – all of these can affect an addict's sense of what possible futures lay open before them.
The addict, even though he did not "choose" his fate in any straightforward sense, still needs to exercise some measure of control; to steer the direction of his life. The medicalization of addiction, Lewis claims, erodes this sense of control by casting the addict as a helpless victim, someone whose fate will be determined by "experts" (if he's lucky) or by the poisons he's been consuming (if he's not).
I admit, I'm one of the lucky ones; I've avoided the kinds of addictions that Lewis has studied (unless you count my fondness for Diet Coke – or for Ms. Pac-Man back in my undergrad days). But I can see what Lewis is trying to do here, as he struggles to reconcile our varying perspectives on addiction. I think he has found a useful balance: Yes, we are biological creatures – but biology is not destiny.
Dan Falk is a science journalist based in Toronto. His books include The Science of Shakespeare and In Search of Time.