The Addictive Brain

Begin by defining "addiction," which is diagnosed based on characteristics such as abuse, dependence, and craving. Professor Polk then surveys the history of drug use, from ancient history through the development of synthetics in the 19th and 20th centuries. Finally, he reviews government regulation and the substantial costs of drug abuse, both to the individual and to society.

Explore the brain's mechanisms for learning from reinforcement. You'll start with the psychological aspects, discovering the way humans learn by a series of trials and rewards. Then you'll find out what parts of the brain process pleasure, self-control, and craving, and see how the psychology and neuroscience of reward processing converge.

Here you'll examine the ways addiction alters the brain by numbing the pleasure center, sensitizing the dopamine system, and inhibiting the prefrontal cortex. Combined, these altered brain functions lead to strong cravings and a reduced ability to control one's actions. This foray into neuroscience will forever change the way you think about addiction.

Investigate how people may be susceptible to addiction on a genetic level. Thanks to studies of twins and DNA analysis, scientists are homing in on the genes that predispose us toward addiction. While there is no single "addiction gene," our DNA can significantly influence whether we become addicts.

Shift your attention from the nature of addiction to the nature of drugs. Here you'll delve into the process of neurochemical transmission and see how drugs mimic this activity by binding to neural receptors. This process is responsible for everything from a drug's physical and psychological effects to its potency.

Caffeine and nicotine are two of the most common psychoactive drugs in our society. How do they work? How dangerous are they? After reviewing how each of these drugs affects the brain - and why nicotine in particular is so addictive - Professor Polk offers several strategies to quit tobacco use.

Alcohol is often discussed separately from other drugs, but as you'll discover, alcohol affects the human body in many of the same ways. Take a close look at your brain on alcohol to explore dependence, withdrawal, and genetic susceptibility. Then review several treatment options for alcohol abuse.

Although there is no shortage of controversy around marijuana, whose legal status now varies from state to state, the science of this drug may surprise you. Through the lens of the neuroscientist, Professor Polk tours the effects, and the possible medicinal value, of marijuana.

From the original recipe for Coca-Cola to treatments for attention deficit disorder, psychostimulant drugs have had remarkable uses. But they have also been dangerously abused in the form of crack cocaine, methamphetamine, and related drugs. Find out how stimulants work in the brain and why they can be so harmful.

Round out your survey of the world's major drugs with an examination of opium and its derivatives, from regularly prescribed painkillers like codeine and morphine to heroin, often considered the most harmful drug of abuse in the world today. Learn about the neurological effects and treatment options for opiate drugs.

Are drugs the only thing humans can get addicted to? What about behaviors? To answer this question, take a look at what happens inside the brain of a compulsive gambler. As this case study reveals, many of the same neurochemical processes of drug abuse - from genetic predisposition to dopamine release - also accompany addiction to behaviors.

Conclude with an exploration of other potentially addictive behaviors. Professor Polk argues that some artificial stimuli - junk food, pornography, and video games to name three - are "supernormal," meaning that they actually activate the brain's reward circuit more strongly than natural stimuli do, leading to some of the same neurological effects as drug use.