Neuroscience Breakthroughs Since Graduate School - Part 2: Addiction
Updated: Mar 24
Addiction inevitably involves loss, including executive functions, health, pleasure from everyday life, productivity, and often relationships. There has been a paradigm shift to a more complete model of addiction that combines negative and positive reinforcement. Although many factors contribute to substance use disorders, stress and deficient dopamine receptors may be crucial. Abused drugs cause direct and indirect dopamine release at the nucleus accumbens. While dopamine begins the reward cascade, addiction involves diverse neurotransmitters. Craving is one of the most dangerous threats to sobriety. Craving emerges from a complex network of subcortical and cortical projections. The loss of brain volume due to apoptosis contributes to hypofrontality, impairing an addict's ability to resist craving and causing relapse. Neurofeedback is an evidence-based treatment for substance use disorder. The Scott-Kaiser modification of the Peniston Protocol plus rehabilitation for substance use disorder has achieved a rating of probably efficacious, comparable to accepted medical treatments. This second installment focuses on the neuroscience of addiction and the efficacy of neurofeedback interventions.
Alcohol is cunning, baffling, and powerful (The Big Book of Alcoholics Anonymous).
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A Paradigm Shift
The view before 1969 was that addiction is fueled by drug dependence. This negative reinforcement model proposed that addicts ingest their next dose to avoid or escape unpleasant withdrawal effects.
Negative reinforcement strengthens the behavior it follows. For example, an addict's "coke runs" can increase the likelihood of drug use by forestalling a cocaine "crash." This is different from punishment, which weakens the behavior by following it with an aversive consequence. Graphic © Suzanne Tucker/Shutterstock.com.
A tragedy of addiction is that punishing outcomes like arrests, job loss, and overdoses often cannot overcome drug craving.
The negative reinforcement model was incomplete because addicts crave drugs after completely withdrawing from them. Graphic © Jan H Andersen/Shutterstock.com.
For example, Vietnam war veterans who had become addicted to high-purity heroin during their service suddenly relapsed after years of sobriety while back in the US. Graphic © Combatcamerauk/Shutterstock.com.
A more complete model of addiction emerged when researchers demonstrated that nonhuman animals will self-administer virtually all the addictive drugs abused by humans. Graphic © Jagodka/Shutterstock.com.