Lance M. Dodes, M.D.

When an addicted person is shown a cue or a trigger (a heroin user watches someone on tv injecting heroin) or in those rat studies when they are placed in an environment where they have been given the drug previously, is there a change in dopamine levels or a surge of some kind of neurotransmitter? And is this what contributes to relapse in recovering addicts?
If so, how does that fit into addiction being psychological and not neurological? Isn't the compulsion to use prompted initially by the brains mechanisms to repeat rewarding behaviour ie release dopamine?

The idea that dopamine levels create addiction is a popular myth. It has arisen from studies of drug-seeking behavior in rats (which is very different from human addiction), and the fact that some people with a history of addiction have increased neurotransmitter levels when exposed to drug-related cues in the environment. But if that were the cause of addiction then nobody with alcoholism would be able to walk past a bar, or, as in your example, nobody with a history of heroin addiction could sit still when viewing drugs. Indeed, if it were true, then anybody with a past history of heavy drug exposure, which might cause increased dopamine levels upon subsequent exposure, would be an addict. In the Robins study of Vietnam veterans, soldiers who had taken enough heroin to become addicted, and who theoretically had developed excessive dopamine release when exposed to subsequent drug-related environmental cues, were able to simply stop using when they returned home. Likewise, if the dopamine idea were correct then anyone who drank heavily or took high doses of narcotics for pain relief would inevitably become an addict. The dopamine idea also cannot explain why people commonly switch from drug addictions to non-drug addictive (compulsive) behaviors. And, of course, it cannot explain why psychological factors regularly produce resumption of addictive behavior.
One reason people have believed the dopamine idea, despite all the evidence against it, is that if fits with the notion that addiction is a reward-seeking behavior. But anyone who suffers with an addiction, or has tried to help a person with addiction, knows that far from being a hedonistic search for pleasure or reward, addiction is a sad compulsion long after any reward has ended. I’ve written about the fallacy of the neurobiological view on many occasions. Please take a look at earlier posts in this blog, including the first post, “Blowing up a myth”. If you are interested in an academic discussion, see my paper, “Addiction as a Psychological Symptom” published in Psychodynamic Practice (2009; 15: 381-393).