Why Some People Are Drug Addicts

Is science finally on the verge of cracking addictions?

We know that addicts lose control over their lives and that they would as soon give up breathing as stop using their preferred substance(s). Yet, the critical question of why one member of an adolescent peer group becomes an addict and the others do not remains open.

The oldest explanation of addiction as a moral weakness is unsatisfactory because it is circular. It does not tell us why some individuals are capable of resisting addiction. Scientists also dislike the moralistic interpretation because it evokes free will that is considered inherently unscientific.

Tossing out the moralistic pseudo-explanation, addiction researchers are left with two plausible theories. According to the disease model, an addict is someone who suffers from a biological vulnerability to some, or all, addictive drugs. The alternative explanation is that drug use is reinforcing and that addicts simply learn to repeat actions that had made them feel good.

The disease theory of addiction

Drug addiction causes all sorts of a medical problem but the disease theory holds that the addict has a biological vulnerability to addiction before they ever began to use the drug.

This perspective underlies the strategy of Alcoholics Anonymous that unquestionably saves many lives and it also seems helpful to family members and to therapists. If the disease theory were correct, it would offer the promise of a medicine that could correct the chemical abnormality of the brain underlying addiction.

Needless to say, there is no such magic bullet and there may never be. The alternative theory focuses on the addictive properties of drugs.

Are addictions learned?

The notion that addiction is produced by reinforcing properties of drugs got a boost from experiments showing that lab animals would work at pressing a lever in order to receive small injections of addictive drugs.

This approach is uniquely helpful in explaining why crack cocaine that is smoked is more addictive than the snorted variety. The smoked variety gets to the brain sooner. The idea is that more immediate reinforcement strengthens the drug-taking behaviour more.

The learning theory of addictions is also backed up by neuroscience because addictive drugs activate dopamine-based reward systems that are designed by natural selection to strengthen naturally-rewarded behaviours such as feeding and mating.

This evolution-based interpretation of learned addictions actually provides an elegant explanation of why addiction occurs. Yet, it does not help in explaining why some individuals get hooked whereas others having a similar drug history do not.

The riddle of who gets addicted

The problem of why some individuals become addicts remains an open question but biological psychologists may be zeroing in on a solution. It has long been known that addicts have underactive dopamine systems and suffer from a decreased capacity to experience pleasure in their ordinary lives.

That is not too surprising because brain receptors tend to get depleted from over-stimulation by the neurotransmitter. Now researchers are reporting genetic abnormalities in dopamine systems that are correlated with addictive tendencies prior to the development of addictions (1).

Reading between the lines, it is possible that some people are more prone to addiction because they obtain less pleasure through natural routes, such as from work, friendships and romantic relationships. That could explain why they are more thrill-seeking, or “stimulus-hungry.”

Dopamine abnormality might also be related to a lack of social inhibition found in some addicts. Alcoholics ignore many of the social conventions about alcohol use, for instance: it should be social; it should never begin before noon; it should be restricted to the evening meal; never have more than three drinks, and so forth.

Supposing that these approaches pan out, we may finally begin to understand why some individuals succumb to addiction. The answer may combine aspects of the disease theory and a sophisticated understanding of the effects of drugs on the brain.

Written by Nigel Barber PhD 2013