Substance-related disorders are an increasing public health concern in the United States. In 2009, of the population aged 12 or older, about 9% reported current use of illicit drugs and 52% reported current use of alcohol. Because these figures were obtained from self-reports, the actual number of American substance users is likely to be even higher (Table 23-1).
Illegal substance-related disorders are more common among young adults aged between 18 and 25 years, and it is about twice as common in males. It is also more common in American Indians or Alaska Natives; rates in this group (18.3%) are at least twice as high as those reported for African Americans (9.6%), whites (8.8%), Hispanic Americans (7.9%), or Asian Americans (3.7%) (Substance Abuse and Mental Health Services Administration, 2010).
For the individual, the use of substances may lead to family, health, and legal problems. For society, the cost of substance-related disorders in the short- and long-term runs into billions of dollars.
It was once believed that substance-related disorders resulted primarily from a lack of self-control. In the last few decades, however, it has become clear that substance use disorders and other addictive illnesses are complex disorders involving social factors as well as genetic, (McHugh et al, 2002) molecular, and cellular modifications in the brain itself. Once effected, these alterations may be difficult or even impossible to reverse, which may explain why substance-related disorders tends to be chronically relapsing. Such findings about the nature of addiction have led to changes both in the attitudes of health care providers and in the design of treatment interventions. The development of new, often multifocal treatment programs can be expected to improve the historically negative outcomes of treatment for individuals affected by addictive illnesses.
• OVERVIEW OF SUBSTANCE-RELATED DISORDERS
Biology of substance-related disorders
Drugs used in substance-related disorders have immediate and long-term effects on the brain. The immediate effect of most misused substances is to increase the availability of neurotransmitters that signal the nervous system to feel pleasure.
The most important of the “feel good” neurotransmitters is dopamine (DA). DA is produced in the neurons of the mesolimbic dopaminergic tract in the area of the ventral tegmentum of the brain. These neurons project forward through the medial forebrain bundle and, when stimulated, release DA toward the nucleus accumbens (NA) and frontal cortex (see Fig. 5-3).
table 23.1 PAST MONTH ALCOHOL AND ILLICIT DRUG USE AMONG PERSONS AGED 12 OR OLDER
A maladaptive pattern of substance use over at least 12 months that leads to impairment of occupational, physical, or social functioning.
Substance dependence
Substance misuse plus withdrawal symptoms, tolerance, or a pattern of compulsive use
Withdrawal
Development of physical or psychological symptoms after the reduction or cessation of intake of a substance
Tolerance
Need for increased amounts of the substance to achieve the same positive physical and psychological effects
Cross-tolerance
Development of tolerance to one substance because of using another substance
Empirical evidence shows the rewarding nature of DA’s action on the NA. Laboratory animals will work to receive electrical stimulation of the NA, and the use of opioids, among the most addicting of substances, causes release of DA from the NA. Other neurotransmitters, such as serotonin and glutamate, are associated with the positive effects of drugs as well. Glutamate is associated specifically with the maintenance of addictive behavior (Nestler & Aghajanian, 1997) and agents that block its activity, such as acamprosate (Campral) (see below), reduce drug cravings. As such, these agents, or agents that prevent glutamate from acting through its major receptor N-methyl-D-aspartate (NMDA) receptor blockers provide an avenue for management of alcohol, cocaine, and heroin addiction (Wickelgren, 1998).
Although the precise mechanisms are not known, long-term exposure to drugs used in substance-related disorders most likely induces changes in neurotransmitter receptors. These changes appear to play a major role in the development of physical addiction and psychological dependence. They explain why repeated use of many substances ultimately leads to both a compulsion to continue using (dependence) and a need for increased doses of the drug to repeat the positive effect (tolerance). Definitions of substance-related disorder, substance dependence, withdrawal, tolerance, and cross-tolerance are listed in Table 23-2.
Classification of misused substances
Most substances can be classified categorically as sedatives, opioids, stimulants, or hallucinogens and related agents. Summaries of the effects of use and withdrawal of these groups can be found in Table 23-3, and a more detailed discussion follows.
Drugs used in substance-related disorders can be administered by many routes. Drug users tend to use routes that provide fast access to the bloodstream and hence the brain, such as injection (which requires special equipment and expertise), sniffing into the nose (snorting), and inhaling (smoking).
Management of substance-related disorders
Because of the neurologic changes effected by use, once dependency develops, abrupt absence of some substances can lead to psychological and physical withdrawal symptoms. Psychological withdrawal symptoms can range from mild irritability to severe depression. Physical withdrawal symptoms can range from the uncomfortable but benign headache associated with withdrawal from stimulants to the life-threatening seizures and cardiovascular collapse associated with withdrawal from barbiturates. Management of the withdrawal symptoms of substance-related disorders includes immediate treatment or detoxification and extended treatment to prevent relapse or maintenance (Table 23-4).
Some substance users also have mental disorders. Patients with diagnoses of both mental illness (e.g., major depression) and substance-use disorder (so-called dual diagnosis or mentally illchemically addicted [MICA] patients) require treatment for both the substance-use disorder and the comorbid psychiatric illness. This treatment must often be provided in a special unit in the hospital.
• SEDATIVES
Sedatives are central nervous system depressants and include alcohol, barbiturates, and benzodiazepines. Although dopaminergic systems are also involved, sedative agents work primarily by increasing the activity of the inhibitory neurotransmitter GABA. The increase in GABA activity results in reduced anxiety as well as sedation.
Alcohol
Alcohol is the most used substance in the world. In the United States, there is a 10% to 13% lifetime prevalence of alcohol use or dependence. Some ethnic groups (e.g., Native Americans) are more likely to use alcohol than others, and men are twice as likely to be users as females.
table 23.3 EFFECTS OF USE AND WITHDRAWAL OF PSYCHOACTIVE SUBSTANCES
CATEGORY
EFFECTS OF USE
EFFECTS OF WITHDRAWAL
Sedatives
Alcohol
Benzodiazepines
Barbiturates
Mood elevation
Decreased anxiety
Sedation
Behavioral disinhibition
Respiratory depression (particularly the barbiturates)
Mood depression
Increased anxiety
Insomnia
Delirium (including psychotic symptoms)
Seizures
Cardiovascular collapse
Opioids
Heroin
Opioids used medically (e.g., methadone, codeine, morphine)
Mood elevation
Decreased anxiety
Sedation
Analgesia
Respiratory depression
Constipation
Pupil constriction
Mood depression
Increased anxiety
Autonomic stability
“Flu-like” symptoms (e.g. muscle aches, sweating)
Piloerection
Yawning
Stomach cramps and diarrhea
Pupil dilation
Stimulants
Amphetamines
Cocaine
Caffeine and nicotine (minor stimulants)
Mood elevation
Insomnia
Deceased appetite
Increased cardiovascular, neurological, and GI activity
Psychotic symptoms
Pupil dilation
Hallucinations (often tactile)
Mood depression
Lethargy
Increased appetite
Decreased cardiovascular, neurological and gastrointestinal activity
The etiology of alcoholism includes genetic and developmental-environmental factors. For example, adopted children tend to show the drinking patterns characteristic of their biological rather than their adoptive parents (see Chapter 5), and behavior problems such as attention-deficit/hyperactivity disorder and conduct disorder correlate with alcoholism in adulthood (see Chapter 2).
Acute use of alcohol is associated with a variety of societal problems, including, but not limited to, suicide (see Chapter 14), traffic accidents, homicide, child physical and sexual abuse, elder abuse, domestic violence, and rape (see Chapter 22). Fetal alcohol syndrome, which includes facial abnormalities, reduced height and weight, intellectual disability, and other problems, is seen in the offspring of women who drink alcohol during pregnancy.
Because people with substance abuse disorders tend to use denial as a defense mechanism (e.g., “I am not an addict because I can stop any time I want to”), a useful strategy to determine if a patient has a problem with alcohol is to ask the patient four specific questions. These “CAGE” questions all begin with “Do you ever …
table 23.4 MANAGEMENT OF USE OF SEDATIVES, OPIOIDS, STIMULANTS
Substitution of long-acting barbiturate (e.g., phenobarbital) or benzodiazepine (e.g., chlordiazepoxide [Librium]) in decreasing doses
Intravenous diazepam (Valium), lorazepam (Ativan), or phenobarbital if seizures occur
Specifically for alcohol: thiamine, and restoration of nutritional state
Education for initiation and maintenance of abstinence for all sedatives
Specifically for alcohol: AA or other peer support group (12-step program), disulfiram (Antabuse), psychotherapy, behavior therapy, acamprosate (Campral), naltrexone (ReVia), topiramate (Topamax)
Opioids
Heroin
Opioids used
medically (e.g., methadone, codeine, morphine)
Hospitalization and naloxone (Narcan) for overdose
Clonidine to stabilize the autonomic nervous system during withdrawal
Substitution of long-acting opioid (e.g., methadone) in decreasing doses to decrease withdrawal symptoms
Methadone or buprenorphine maintenance program
Naltrexone or buprenorphine plus naloxone (Suboxone) used prophylactically to block the effects of opioids
Narcotics Anonymous or other peer support program
Stimulants
Amphetamines
Cocaine
Benzodiazepines to decrease agitation
Antipsychotics to treat psychotic symptoms
Medical and psychological support
Education for initiation and maintenance of abstinence
Minor stimulants
Caffeine
Nicotine
Eliminate or taper from the diet
Analgesics to control headache due to withdrawal
Substitute decaffeinated beverage
Nicotine-containing gum, patch, nasal spray
Antidepressants (particularly bupropion [Zyban]) to prevent smoking
Peer support group (e.g., “Smokenders”)
Support from family members or nonsmoking physician
Hypnosis to prevent smoking
Hallucinogens and related agents
Marijuana
Hashish
LSD
PCP
Psilocybin
Mescaline
Calming or “talking down” the patient
Benzodiazepines to decrease agitation
Antipsychotics to treat psychotic symptoms
Education for initiation and maintenance of abstinence
get Angry when someone comments on your drinking?”
feel Guilty about your drinking?”
take a drink as an Eye-opener in the morning?”
A positive answer to any two of the CAGE questions or to just the last question indicates that the patient has a problem with alcohol.
Chronic, heavy use of alcohol results in several serious physical disorders. These include Wernicke and Korsakoff syndromes (see Chapter 14) as well as liver dysfunction and gastrointestinal problems, such as peptic ulcers and pancreatitis.
Although the dangers of heavy drinking are well established, moderate use of alcohol may have positive effects on health. In long-term studies, patients who drank alcohol “moderately” (up to one drink [defined as 12 oz (355 ml) of beer, 5 oz (148 ml) of wine, or 1.5 oz (44 ml) of 80-proof distilled spirits] per day for women and up to two drinks per day for men), showed cardiovascular benefits, such as fewer heart attacks, than in nondrinkers or in those who had one or two drinks only 1 or 2 days a week (Mukamal, 2003
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