Home / Courses / Abnormal Psychology / Unit 8

Abnormal Psychology Unit 8: Substance-Related and Addictive Disorders

Substance use disorders involve a problematic pattern of use that leads to impaired control, social problems, risky use and physical changes such as tolerance and withdrawal. This unit covers the major drug classes, why addiction develops and how it is treated.

Covers: DSM-5-TR criteria and severity for substance use disorders, Intoxication, tolerance and withdrawal, Depressants: alcohol and sedatives, Opioids and overdose, Stimulants, cannabis and hallucinogens, Biological and psychological theories of addiction, Treatment: medication, motivational and behavioral approaches, Gambling disorder

Study guide

The DSM-5-TR diagnoses a substance use disorder when a problematic pattern of use leads to clinically significant impairment or distress, shown by at least two of eleven criteria within a 12-month period. The criteria fall into four groups: impaired control (using more than intended, failed efforts to cut down, much time spent, craving), social impairment (failing major obligations, continued use despite social problems, giving up activities), risky use (use in hazardous situations, continued use despite physical or psychological harm) and pharmacological criteria (tolerance and withdrawal). Severity is mild with two or three criteria, moderate with four or five and severe with six or more. Tolerance means needing more of a substance for the same effect, and withdrawal is a substance-specific syndrome when use stops. Tolerance and withdrawal from medications taken as prescribed do not count. Gambling disorder is the one behavioral addiction in the chapter.

Depressants slow the central nervous system. Alcohol enhances GABA and inhibits glutamate. In the United States a standard drink contains about 14 grams (0.6 ounces) of pure alcohol, roughly 12 ounces of 5% beer, 5 ounces of 12% wine or 1.5 ounces of 40% spirits. Long-term heavy use can cause liver disease and Korsakoff syndrome, a memory disorder linked to thiamine (vitamin B1) deficiency, and use during pregnancy can cause fetal alcohol spectrum disorders. Alcohol withdrawal can be dangerous, with tremors, seizures or delirium tremens. Sedatives such as benzodiazepines and barbiturates also act on GABA, and mixing them with alcohol is especially dangerous. Opioids, including heroin, oxycodone and fentanyl, bind to opioid receptors that normally respond to endorphins, relieving pain and producing euphoria. The main danger of opioid overdose is slowed breathing, which the medication naloxone can reverse.

Stimulants increase alertness and energy. Cocaine blocks the reuptake of dopamine, norepinephrine and serotonin, and amphetamines and methamphetamine increase their release. Stimulant intoxication can cause euphoria, rapid heart rate and, at high doses, paranoia or psychosis, and withdrawal often brings a crash of fatigue and depressed mood. Nicotine is a stimulant that is highly addictive, and tobacco use remains a leading preventable cause of death. Cannabis, whose main psychoactive compound is THC, acts on cannabinoid receptors, impairs memory and coordination, and heavy adolescent use is linked to higher risk of psychosis in vulnerable people. Hallucinogens such as LSD and psilocybin act mainly on serotonin receptors and alter perception; they produce little physical dependence. Nearly all addictive drugs increase dopamine in the brain's reward pathway, from the ventral tegmental area to the nucleus accumbens.

Many factors contribute to addiction. Twin studies estimate the heritability of alcohol use disorder at about 50%, and some genes are protective: a variant of the ALDH2 gene, common in East Asian populations, causes unpleasant flushing after drinking and lowers risk. Robinson and Berridge's incentive-sensitization theory proposes that repeated use makes the brain's 'wanting' system hypersensitive to drug cues even as 'liking' fades. Solomon's opponent-process theory says that each drug effect is followed by an opposite reaction that grows stronger over time, so users increasingly take the drug to escape withdrawal. Psychological factors include positive and negative reinforcement, the tension-reduction hypothesis, and expectancies about what a drug will do. Sociocultural factors include peer use, availability, advertising, poverty and cultural norms about drinking.

Treatment begins, when needed, with medically supervised detoxification. Medications for opioid use disorder include methadone (a full opioid agonist), buprenorphine (a partial agonist) and naltrexone (an antagonist); they cut overdose deaths and are considered the standard of care. For alcohol, disulfiram makes drinking cause nausea, naltrexone reduces craving and reward, and acamprosate eases protracted withdrawal. Psychological treatments include motivational interviewing (William Miller and Stephen Rollnick), which resolves ambivalence about change; cognitive-behavioral relapse prevention (G. Alan Marlatt), which teaches people to handle high-risk situations and avoid the abstinence violation effect, the all-or-nothing belief that one slip means total failure; and contingency management, which gives vouchers or prizes for drug-free tests. Twelve-step programs such as Alcoholics Anonymous offer peer support. Harm reduction aims to reduce damage, as with naloxone distribution. Prochaska and DiClemente's stages of change model guides when to use which approach.

Key ideas

• Substance use disorder requires at least 2 of 11 criteria in 12 months; severity depends on the number of criteria.
• Tolerance and withdrawal are neither necessary nor sufficient for a diagnosis, and they do not count for properly prescribed medications.
• Depressants (alcohol, sedatives) act on GABA; opioids act on opioid receptors; stimulants boost dopamine and norepinephrine.
• Most addictive drugs raise dopamine in the reward pathway from the ventral tegmental area to the nucleus accumbens.
• Addiction reflects genes, brain changes, learning, expectancies and social context together.
• Medications for opioid use disorder, such as methadone and buprenorphine, lower overdose deaths.
• Motivational interviewing, relapse prevention and contingency management are well-supported psychological treatments.

Formulas and rules

Common mistakes

• Thinking a diagnosis requires tolerance or withdrawal; a person can meet criteria through control, social and risk criteria alone.
• Counting tolerance to a properly prescribed pain medication as a symptom of opioid use disorder.
• Confusing naloxone (rapid overdose reversal) with naltrexone (longer-term relapse prevention).
• Treating a single slip as proof that treatment failed, which is the abstinence violation effect.
• Assuming hallucinogens produce strong physical withdrawal like alcohol or opioids.

Before the test, make sure you can

• List the four groups of substance use disorder criteria and assign severity from a criteria count.
• Define intoxication, tolerance and withdrawal and explain when they do not count.
• Calculate standard drinks from a beverage's size and alcohol content.
• Describe the effects and brain mechanisms of depressants, opioids, stimulants, cannabis and hallucinogens.
• Explain the reward pathway, incentive-sensitization and opponent-process theories.
• Compare methadone, buprenorphine, naltrexone and naloxone.
• Describe motivational interviewing, relapse prevention, contingency management and the stages of change.

Words to know

Substance use disorder

A problematic pattern of substance use meeting at least 2 of 11 DSM-5-TR criteria within 12 months.

Intoxication

A reversible, substance-specific syndrome of behavioral or psychological changes caused by recent use.

Tolerance

The need for increasing amounts of a substance to achieve the same effect, or reduced effect from the same amount.

Withdrawal

A substance-specific set of symptoms that develops when heavy, prolonged use stops or is reduced.

Craving

A strong desire or urge to use a substance, one of the DSM-5-TR criteria.

Standard drink

In the U.S., a drink containing about 14 grams (0.6 ounces) of pure alcohol.

Korsakoff syndrome

A memory disorder linked to thiamine deficiency, often from long-term heavy alcohol use.

Delirium tremens

A severe alcohol withdrawal state with confusion, agitation, hallucinations and autonomic instability.

Naloxone

An opioid antagonist that rapidly reverses opioid overdose.

Methadone

A long-acting full opioid agonist used to treat opioid use disorder.

Buprenorphine

A partial opioid agonist that reduces craving and withdrawal with a lower overdose risk than full agonists.

Reward pathway

The mesolimbic dopamine circuit from the ventral tegmental area to the nucleus accumbens.

Incentive-sensitization theory

Robinson and Berridge's view that repeated use sensitizes drug 'wanting' even as 'liking' declines.

Motivational interviewing

A collaborative counseling style that helps people resolve ambivalence and strengthen their own motivation to change.

Contingency management

A behavioral treatment that gives tangible rewards for verified abstinence.

Abstinence violation effect

Marlatt's term for the belief that a single slip means complete failure, which can trigger full relapse.

Harm reduction

An approach that aims to reduce the negative consequences of substance use rather than requiring immediate abstinence.

Gambling disorder

Persistent and recurrent problematic gambling that causes distress or impairment, the behavioral addiction in the DSM-5-TR.

Sample practice questions

30 more questions like these, from level 1 to 5, are in the practice set.