9.6 SUMMING UP

Substance Use: When Use Becomes a Disorder

• The hallmark of substance use disorders is loss of control over urges to use a psychoactive substance, even though such use might lead to significant problems.
• The term addiction focuses on the compulsive behaviors related to regular drug taking but is not used in DSM-5.
• Tolerance and withdrawal are symptoms of substance use disorders.
• The common liabilities model focuses on underlying factors that may contribute to a variety of problem behaviors, including substance use disorders. The gateway hypothesis focuses on factors that lead individuals to progress from using entry drugs to using harder drugs.
• Substance use disorders frequently co-occur with mood disorders (particularly depression), PTSD, schizophrenia, and ADHD. Many people with substance use disorders engage in polysubstance abuse.
• Cultures can promote or regulate substance use through the use of rituals and penalties.

Stimulants

• Stimulants, which increase arousal and brain activity, are the psychoactive substances in which use is most likely to lead to a use disorder. Unlike many other types of drugs, they act directly—rather than indirectly—on the dopamine reward system by binding to dopamine transporters in the synapse.
• Stimulants include cocaine and crack, amphetamines, methamphetamine, Ritalin, MDMA, and nicotine. In high doses, most of these stimulants can cause paranoia and hallucinations. With continued use, stimulants lead to tolerance and withdrawal.
• A neurological factor that contributes to substance use disorders is activation of the dopamine reward system.
• Psychological factors related to substance use disorders include operant reinforcement of the effects of the drug, classical conditioning of stimuli related to drug use, and observational learning of expectancies about the effects of drugs and their use of them.
• Social factors related to substance use disorders include the specific nature of a person’s relationships with family members, socioeconomic factors, and cultural and perceived norms about appropriate and inappropriate uses of substances.

Depressants

• Depressants decrease arousal, awareness, and nervous system activity. Depressants include alcohol, barbiturates, and benzodiazepines.
• Continued use of depressants leads to tolerance and withdrawal. Some withdrawal symptoms are potentially lethal; people with a depressant use disorder should be medically supervised while tapering off the use of the drug.
• The effects of alcohol depend on its concentration in the blood. Repeated binge drinking can lead to alcohol use disorder. Long-term alcohol use disorder is associated with a variety of cognitive problems, as well as atrophy of certain brain areas and enlarged ventricles. Withdrawal symptoms include delirium tremens.
• Depressants directly affect the GABAnergic neurotransmitter system, which in turn dampens activity in key brain areas that give rise to anxiety. Depressants also indirectly activate the dopamine reward system.
• Psychological factors related to depressant use disorders include observational learning to expect specific effects from depressant use and to use depressants as a coping strategy, positive and negative reinforcement of the effects of the drug, and classical conditioning of drug cues that leads to cravings.
• Social factors related to depressant use disorders include the nature of a person’s relationships with family members, peers’ use of depressants, and norms and perceived norms about appropriate and inappropriate use of depressants.

Other Abused Substances

• Exogenous opioids can dull pain and decrease awareness. Continued opioid use quickly leads to tolerance and withdrawal, as well as compulsive drug-related behaviors. Heroin is an opioid. Opioids activate the dopamine reward system. They also depress the central nervous system and decrease endorphin production, thereby reducing the body’s inherent ability to relieve pain.
• Hallucinogens include LSD, mescaline, psilocybin, and marijuana. Hallucinogens have unpredictable effects, which depend in part on the user’s expectations and the context in which the drug is taken. LSD affects serotonin functioning.
• Cannabis use disorder affects motivation, learning, and memory. The active ingredient in marijuana, THC, activates the dopamine reward system. Chronic marijuana users may develop withdrawal.
• Dissociative anesthetics (sometimes referred to as “club drugs”) are so named because they induce a sense of dissociation and cause anesthesia. Dissociative anesthetics include PCP and ketamine. Use and abuse of this type of drug impairs cognitive functioning and can lead to violent behavior.
• Genes may predispose some people to develop a substance use disorder.
• Psychological factors related to other substance use disorders include observational learning of what to expect from taking the drugs and of using the drugs as a coping strategy. Classical conditioning of stimuli related to drug use can lead to cravings and can play a role in building tolerance. In addition, the disorders may arise in part from operant conditioning.
• Social factors related to other substance use disorders include the person’s relationships with family members, peers’ use of substances, cultural norms and perceived norms about appropriate and inappropriate use of substances, and socioeconomic factors.

Treating Substance Use Disorders

• A treatment that focuses on neurological factors is detox to help reduce symptoms of withdrawal that come from substance use disorders. Medications may reduce unpleasant withdrawal symptoms or block the pleasant effects of using the substance, which can help maintain abstinence.
• Treatments that target psychological factors, such as motivational enhancement therapy, are designed to motivate people to decrease substance use. CBT addresses antecedents, consequences, and specific behaviors related to substance use. Twelve-Step Facilitation provides structure and support to help patients abstain.
• Social factors are targeted by residential treatment and other types of community-based treatment (group therapy and self-help groups), as well as family therapy to address issues of communication, power, and control.