T. Evarts
Compulsive drug use is not a choice. Drug addiction is caused by changes in the brain emotional biochemistry, not a weak moral character. Biochemical reactions are caused by neurotransmitter functions. The data show significant differences in neurotransmitter functions between an addict and a non-user. Neurotransmitters in an addict cause the compulsive use of drugs, rejecting the misconception that addiction is a choice, rather than a disease.
Drug use produces a sense of euphoria caused by a burst of neurotransmitters. The euphoric experience, or high, positively reinforces the act of using the drug. At the end of a high, the body attempts to return to its normal state, and neurotransmitter levels decrease belownormal, causing withdrawal. It is common to use drugs again to alleviate withdrawal symptoms. Unfortunately, more drugs reinforce the use of the drug (negative reinforcement). Positive and negative reinforcement contribute to compulsivity, however, negative reinforcement (blue) affects addicts more because of reduced reward neurotransmitter function which leads to the intensified urges to use drugs. The difference between negative and positive reinforcement shown in the data is caused by the impact neurotransmitters have on an addict and a non-user’s brain. The non-user experiences a high level of positive reinforcement and a very low level of negative reinforcement while an addict has the opposite reaction. The pattern of reinforcement caused by the neurotransmitter activity is what gives an addict the urge to use. One could argue that because the same neurotransmitters are released in both subjects, drug use is based on choice. The bold arrows represent the greater impact neurotransmitters have on reinforcement type. Although the same neurotransmitters are released, their reward stimulus differs significantly between an addict and a non-user.
Addiction is driven by the biochemical urge to use drugs which an addict cannot control. Positive and negative reinforcement resulting from neurotransmitter activity in the non-user is inverted from the addict’s, showing the difference in brain function that leads to compulsive drug use. Difference in neurotransmitter release is not a choice, and neither is addiction.
Koob et al., Annu. Rev. Psychol., Volume 59, 2008
