Psychoactive Drugs and Addiction
Learning Objectives
- Describe how substance abuse disorders are diagnosed
Substance Abuse Disorders
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is used by clinicians to diagnose individuals suffering from various psychological disorders. Drug use disorders are addictive disorders, and the criteria for specific substance (drug) use disorders are described in DSM-5. A person who has a substance use disorder often uses more of the substance than they originally intended to and continues to use that substance despite experiencing significant adverse consequences. In individuals diagnosed with a substance use disorder, there is a compulsive pattern of drug use that is often associated with both physical and psychological dependence.
Physical dependence involves changes in normal bodily functions—the user will experience withdrawal from the drug upon cessation of use. In contrast, a person who has psychological dependence has an emotional, rather than physical, need for the drug and may use the drug to relieve psychological distress. Tolerance is linked to physiological dependence, and it occurs when a person requires more and more drug to achieve effects previously experienced at lower doses. Tolerance can cause the user to increase the amount of drug used to a dangerous level—even to the point of overdose and death.
Drug withdrawal includes a variety of negative symptoms experienced when drug use is discontinued. These symptoms usually are opposite of the effects of the drug. For example, withdrawal from sedative drugs often produces unpleasant arousal and agitation. In addition to withdrawal, many individuals who are diagnosed with substance use disorders will also develop tolerance to these substances. Psychological dependence, or drug craving, is a recent addition to the diagnostic criteria for substance use disorder in DSM-5. This is an important factor because we can develop tolerance and experience withdrawal from any number of drugs that we do not abuse. In other words, physical dependence in and of itself is of limited utility in determining whether or not someone has a substance use disorder.
Link to Learning
Read through this fascinating comic created by Stuart McMillen about psychologist’s Bruce Alexander’s Rat Park study on addiction.
For more information on Bruce Alexander’s study and a better understanding of addiction, listen to Johann Hari’s TED Talk, “Everything you think you know about addiction is wrong.”
Drug Categories
The effects of all psychoactive drugs occur through their interactions with our endogenous neurotransmitter systems. Many of these drugs, and their relationships, are shown in Figure 1. As you have learned, drugs can act as agonists or antagonists of a given neurotransmitter system. An agonist facilitates the activity of a neurotransmitter system, and antagonists impede neurotransmitter activity.
The main categories of drugs are depressants, stimulants, and hallucinogens. You’ll learn more about these types drugs in the coming pages.
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- Substance Use and Abuse. Authored by: OpenStax College. Located at: https://openstax.org/books/psychology-2e/pages/4-5-substance-use-and-abuse. License: CC BY: Attribution. License Terms: Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction.
changes in normal bodily functions that cause a drug user to experience withdrawal symptoms upon cessation of use
emotional, rather than a physical, need for a drug which may be used to relieve psychological distress
state of requiring increasing quantities of the drug to gain the desired effect
variety of negative symptoms experienced when drug use is discontinued
chemical substances that alters brain functioning, causing changes to consciousness, perception, mood, and thoughts
drug that tends to suppress central nervous system activity
drug that tends to increase overall levels of neural activity; includes caffeine, nicotine, amphetamines, and cocaine
one of a class of drugs that results in profound alterations in sensory and perceptual experiences, often with vivid hallucinations