Addiction doesn't just happen; it's learned

Most scientific research ends up as unread papers published in arcane journals with boring titles. Now and then, for better or worse, some of their findings make it into public discourse and popular culture. The latest findings on the biochemistry of drug addiction by Wei Liping of Peking University, and her team, cry out for the public attention they deserve.

They go a long way towards explaining why some people are more prone to addiction and why it is so difficult to shake off once addiction has started. They will, hopefully, enlighten those in charge of catching, jailing and rehabilitating addicts, and educating others, to develop a better scientific understanding of the matter. Until then, anti-drug policies will always risk being counterproductive and even increasing the costs of addiction to society.

There are usually two opposing social attitudes towards addicts and how to treat them. One may be described as moralistic, portraying those who are tempted to experiment, and those already addicted, as having a choice to stop before their lives are ruined. This is the common message from the latest series of government TV commercials on addiction. One such commercial features a young drug addict as having a breakdown, surrounded by onlookers, in a crowded street. A voiceover warns people not to be tempted to experiment with drugs because they can't stop once they start.

Another public attitude is more liberal, or medical, and is inclined to treat addiction as something like a 'normal' disease. In this view, character, willpower and personal choices are largely irrelevant. Addicts are just like patients with a physical sickness.

Dr Wei's team, whose findings are published in The Public Library of Science (www.plos.org), may have found a middle path, showing that both sides need to revise their basic assumptions. Contemporary neuroscience, on which Dr Wei's work is based, has found something that is perhaps highly disturbing to some people: at a neurological level, learning new things like calculus and historical facts may be indistinguishable from developing an addiction.

Learning is, essentially, transforming sensory experiences into long-term memories and skills. This is achieved by forming new connections between nerve cells (also called neurons) through synapses, the gaps through which neurons communicate with one another. The 'wiring' of these connections and their networks enable us to learn new things and improve skills.

In an exhaustive review of the existing literature, Dr Wei's team has identified a small group of genes that encode pathways of enzymes implicated in addictions to alcohol, cocaine, nicotine and opiates, as well as the formation of neuron networks that underlie learning. Once you have mastered something, such as riding a bicycle or a set of equations, it is very difficult to unlearn it. It is, neurologically, the same with addiction, which is why it is so difficult to quit.

What do pathways and enzymes have to teach policymakers, judges, social workers, therapists and law enforcement officers? Nothing directly, perhaps, but a proper scientific outlook provides a context for them to exercise their duties. Yes, social environment and external factors have an influence on addicts, but genetics and neurological causes also play a crucial part. So, character strength and psychological determination may not be enough for addicts to quit their persistent habits. And, because of the plasticity of neuron networks, some people are more prone to addiction than others, but not necessarily because of moral defects.

On the other hand, 'moralists' may be right to warn people not to experiment with drugs, because the risks they face cannot be predetermined accurately. Addiction triggers biochemical processes which are likely to be irreversible.

Dr Wei's work may, hopefully, provide a more scientific and humane framework for our understanding of this social plague.

Alex Lo is a senior writer at the Post