It has been very useful for western society to classify addiction as a disease, according to Marc Lewis, a Toronto neuroscientist. That has let drug users understand their cravings as something that can be dealt with within existing health-care systems. It has also allowed doctors to treat addiction with pharmaceutical tools like methadone and permitted policymakers to spend money on drug-rehabilitation programs the same way governments fund research for conditions such as diabetes.
On the line from the Netherlands, where he teaches developmental psychology at Radboud University, Lewis conceded that the conception of addiction he proposes in his new book, The Biology of Desire: Why Addiction Is Not a Disease, risks upending all of that.
“The criticism that I’ve gotten says that if you stop calling it a disease, if you take away our health-care system—the institutional network that we have for dealing with addicts—that addicts won’t get treated,” he told the Georgia Straight. “That is a valid concern, but I think it is shortsighted.”
Lewis will present a long-term alternative when he travels to Vancouver on August 4 for an event, organized by the Portland Hotel Society, that is timed to coincide with the Canadian publication of his book.
In The Biology of Desire, he argues that addiction is not a disease but a learned habit, a normal process of the brain’s development, albeit a destructive one.
“The repetition of particular experiences modifies synaptic networks,” he writes. “This creates a feedback cycle between experience and brain change, each one shaping the other. New patterns of synaptic connections perpetuate themselves like the ruts carved by rainwater in the garden. The take-home message? Brain changes naturally settle into brain habits—which lock into mental habits.”
In easily digestible anecdotes, Lewis presents the lives of characters like Natalie, a university student who slowly transitioned from prescription opioids to heroin. Alternating real-life stories and descriptions of neurological changes happening at a molecular level, Lewis delivers step-by-step explanations of the ways that physical actions involving drugs impact the brain to create feedback loops. Over time and through repeated behaviour, those effects change how the brain functions.
For example, dopamine uptake to the striatum—the part of the forebrain that receives input from the cerebral cortex—evolves to prioritize short-term rewards over long-term planning. At the same time, synaptic pruning results in a loss of communication between different brain systems that regulate self-control.
These changes are not the result of a disease or dominant genetic predisposition, Lewis maintained, but are the predictable results of behaviour patterns and environmental impacts.
“When people talk about an addiction gene or a cluster of genes for addiction, it is just not right; it is just not scientifically valid,” he argued. “What I wanted to do is to launch an alternative based on the science, and on the neuroscience in particular, as well as the stories of addicts.”
Lewis, whose 2012 book, Memoirs of an Addicted Brain, lays bare his own past struggles with drugs, said that as long as we continue to incorrectly describe addiction as a disease, we prevent society from developing an understanding that allows us to more effectively help people get better.
His work makes a strong case for a paradigm shift, but The Biology of Desire presents no silver bullets.
“Whether you see addiction as a disease or as a learning phenomenon, it isn’t clear exactly how you fix it,” Lewis said. But, Lewis added, the first step must be acknowledging that addiction as a concept is something more complicated than a disease.
Marc Lewis will speak at 7 p.m. on Tuesday (August 4) at the Goldcorp Centre for the Arts at SFU Woodward's.