Chapter 16 covers the topics of autistic disorder, stress diorders, and drug abuse. The opening section of the chapter provides a description of autism, a disorder characterized by poor emotional development. Abnormal prenatal development may contribute to autism. The next chapter section describes the stress process and links aversive stimuli (stressors) to hormonal stress responses (secretion of epinephrine and the glucocorticoids). Chronic stress is related to the damaging effects of glucocorticoids on organs and on the immune system. The final chapter section distinguishes between physical and psychological addiction, and introduces the concept of drug dependence. Addiction involves elements of both positive and negative reinforcement. The biological basis of addiction to opiates, cocaine, alcohol, nicotine, cannabis, and the hallucinogens is discussed. A common feature for the abuse of each drug is related to drug action on dopaminergic cells within the nucleus accumbens. The heritability of drug abuse in humans is discussed as are treatments for drug abuse.

After completing the chapter, each student should be able to:

• Describe the symptoms and causes of autism.
• Describe the physiological responses to stress and their consequences on health.
• Discuss several of the long term consequences of stress including posttraumatic stress disorder and cardiovascular disease.
• Discuss psychoneuroimmunology and the interactions between stress and the immune system.
• Review general characteristics and definitions of addiction.
• Contrast positive and negative reinforcement.
• Review the neural basis of the reinforcing effects and withdrawal effects of the opiates.
• Describe the behavioral and pharmacological effects of cocaine, amphetamine, and nicotine.
• Describe the behavioral and pharmacological effects of alcohol, barbiturates, and cannabis.
• Describe research on the role of heredity in human drug addiction.
• Discuss methods of therapy for drug abuse.