Additional information on cannabis-related disorders
Additional Information on Cannabis-Related Disorders
Associated Features and Disorders
Associated descriptive features and mental disorders.
Cannabis is often used with other substances, especially nicotine, alcohol, and cocaine. Cannabis (especially marijuana) may be mixed and smoked with opioids, phencyclidine (PCP), or hallucinogenic drugs. Individuals who regularly use cannabis often report both physical and mental lethargy and anhedonia. Mild forms of depression, anxiety, or irritability are seen in about one-third of individuals who regularly use cannabis (daily or almost daily). When taken in high doses, cannabinoids have psychoactive effects that can be similar to those of hallucinogens (e.g., lysergic acid diethylamide [LSD]), and individuals who use cannabinoids can experience adverse mental effects that resemble hallucinogen-induced "bad trips." These range from mild to moderate levels of anxiety (e.g., concern that the police will discover the substance use) to severe anxiety reactions resembling Panic Attacks. There may also be paranoid ideation ranging from suspiciousness to frank delusions and hallucinations. Episodes of depersonalization and derealization have also been reported. Fatal traffic accidents have been found to occur more often in individuals who test positive for cannabinoids than in the general population. However, the significance of these findings is unclear because alcohol and other substances are often also present.
Associated laboratory findings.
Urine tests generally identify cannabinoid metabolites. Because these substances are fat soluble, persist in bodily fluids for extended periods of time, and are excreted slowly, routine urine tests for cannabinoids in individuals who use cannabis casually can be positive for 7-10 days; urine of individuals with heavy use of cannabis may test positive for 2-4 weeks. A positive urine test is only consistent with past use; it does not establish Intoxication, Dependence, or Abuse. Biological alterations include temporary (and probably dose-related) suppression of immunological function and suppressed secretion of testosterone and luteinizing hormone (LH), although the clinical significance of these alterations is unclear. Acute cannabinoid use also causes diffuse slowing of background activity on EEG and rapid eye movement (REM) suppression.
Associated physical examination findings and general medical conditions.
Cannabis smoke is highly irritating to the nasopharynx and bronchial lining and thus increases the risk for chronic cough and other signs and symptoms of nasopharyngeal pathology. Chronic cannabis use is sometimes associated with weight gain, probably resulting from overeating and reduced physical activity. Sinusitis, pharyngitis, bronchitis with persistent cough, emphysema, and pulmonary dysplasia may occur with chronic, heavy use. Marijuana smoke contains even larger amounts of known carcinogens than tobacco.
Specific Culture, Age, and Gender Features
Cannabis is probably the world's most commonly used illicit substance. It has been taken since ancient times for its psychoactive effects and as a remedy for a wide range of medical conditions. It is among the first drugs of experimentation (often in the teens) for all cultural groups in the United States. As with most other illicit drugs, Cannabis Use Disorders appear more often in males, and prevalence is most common in persons between ages 18 and 30 years.
Prevalence
Cannabinoids, especially cannabis, are also the most widely used illicit psychoactive substances in the United States. Although the lifetime prevalence figures slowly decreased in the 1980s, modest increases were reported between 1991 and 1997, especially among youth. A 1996 national survey of drug use noted that 32% of the U.S. population reported ever having used a cannabinoid. Almost 1 in 11 had used it in the prior year, and around 5% had used it in the past month. The age span with the highest lifetime prevalence was 26 to 34 years (50%), but use in the last year (24%) and last month (13%) was most common in 18- to 25-year-olds. Among those who used in the prior year, 5% had taken a cannabinoid at least 12 times, and 3% had taken one on more than 50 days. Regarding use of cannabis in adolescents and young adults, a 1995 survey found that 42% of high school seniors had ever used a cannabinoid, including 35% in the prior year. Because the surveys assessed patterns of use rather than disorders, it is not known how many of those who used marijuana had symptoms that met criteria for Dependence or Abuse.
A 1992 national survey conducted in the United States reported lifetime rates of Cannabis Abuse or Dependence of almost 5%, including 1.2% in the prior year.
Course
Cannabis Dependence and Abuse usually develop over an extended period of time, although the progression might be more rapid in young people with pervasive conduct problems. Most people who become dependent typically establish a pattern of chronic use that gradually increases in both frequency and amount. With chronic heavy use, there is sometimes a diminution or loss of the pleasurable effects of the substance. Although there may also be a corresponding increase in dysphoric effects, these are not seen as frequently as in chronic use of other substances such as alcohol, cocaine, or amphetamines. A history of Conduct Disorder in childhood or adolescence and Antisocial Personality Disorder are risk factors for the development of many Substance-Related Disorders, including Cannabis-Related Disorders. Few data are available on the long-term course of Cannabis Dependence or Abuse. As with alcohol, caffeine, and nicotine, cannabinoid use appears early in the course of substance use in many people who later go on to develop Dependence on other substances-an observation that has led to speculation that cannabis might be a "gateway drug." However, the social, psychological, and neurochemical bases of this possible progression are not well understood, and it is not clear that marijuana actually causes individuals to go on to use additional types of substances.
Differential Diagnosis
For a general discussion of the differential diagnosis of Substance-Related Disorders, see p. 207. Cannabis-Induced Disorders may be characterized by symptoms (e.g., anxiety) that resemble primary mental disorders (e.g., Generalized Anxiety Disorder versus Cannabis-Induced Anxiety Disorder, With Generalized Anxiety, With Onset During Intoxication). See p. 210 for a discussion of this differential diagnosis. Chronic intake of cannabis can produce a lack of motivation that resembles Dysthymic Disorder. Acute adverse reactions to cannabis should be differentiated from the symptoms of Panic Disorder, Major Depressive Disorder, Delusional Disorder, Bipolar Disorder, or Schizophrenia, Paranoid Type. Physical examination will usually show an increased pulse and injected conjunctivas. Urine toxicological testing can be helpful in making a diagnosis.
In contrast to Cannabis Intoxication, Alcohol Intoxication and Sedative, Hypnotic, or Anxiolytic Intoxication frequently decrease appetite, increase aggressive behavior, and produce nystagmus or ataxia. Hallucinogens in low doses may cause a clinical picture that resembles Cannabis Intoxication. PCP, like cannabis, can be smoked and also causes perceptual changes, but Phencyclidine Intoxication is much more likely to cause ataxia and aggressive behavior. Cannabis Intoxication is distinguished from the other Cannabis-Induced Disorders (e.g., Cannabis-Induced Anxiety Disorder, With Onset During Intoxication) because the symptoms in these latter disorders are in excess of those usually associated with Cannabis Intoxication and are severe enough to warrant independent clinical attention.
The distinction between occasional use of cannabis and Cannabis Dependence or Abuse can be difficult to make because social, behavioral, or psychological problems may be difficult to attribute to the substance, especially in the context of use of other substances. Denial of heavy use is common, and people appear to seek treatment for Cannabis Dependence or Abuse less often than for other types of Substance-Related Disorders.