Cannabis Compound Abuse

PAGE 7

Cannabis Compound Abuse

Marijuana was introduced to the Western Hemisphere in the early 1500s. African slaves brought marijuana plants with them to the Portuguese colony of Brazil, while the Spaniards began growing it in Chile.

Cannabis was introduced to the Virginia colony of Jamestown in 1611 and to the Massachusetts Bay Colony in 1629. Although primarily used as a source of fiber, cannabis occasionally was smoked. Cannabis began to be used medicinally and was grown by many American planters. In the United States, recreational abuse of marijuana became more common in the early 20th century. Marijuana was enjoyed with bathtub gin in the Prohibition Era (1920s). In the 1960s, marijuana use became associated with the widespread cultural changes. As a result of the Comprehensive Drug Abuse Prevention and Control Act of 1970, the penalties for marijuana use became substantially less than the penalties for other drugs such as cocaine or heroin. The medicinal use of cannabis currently is the subject of intense legal and medical debate in the United States.

Pathophysiology: Cannabis contains several pharmacologically active substances, of which, the most powerful psychoactive member is delta-l-tetrahydrocannabinol (THC). Pyrolysis of marijuana releases more than 100 substances that are subsequently inhaled with the smoke. Little is known about how marijuana exerts its psychological effects at the CNS cellular level. Most of the hypothesized activities of marijuana are based upon associative evidence. Because marijuana has sedative effects, some studies have hypothesized activation of benzodiazepine (BZ) receptors in the limbic system and cerebellum. Other studies have viewed the sedating properties as potential evidence of GABA receptor activity.

THC binding sites are known to be distributed widely throughout the brain. The density of these sites is highest in the basal ganglia and cerebellum. They are moderately dense in the hippocampus and cortex. These sites of action may partially account for the psychotoxic effects of the drug.

Frequency: In the US: Marijuana remains the most commonly used illicit drug in the United States. According to data from the 1998 National Household Survey on Drug Abuse (NHSDA), more than 72 million Americans (33%) aged 12 years and older have tried marijuana at least once in their lifetimes. Internationally: Rates of abuse vary widely. The hypothesis that cannabis is the most widely used illicit drug in most Western countries is generally accepted.

Race: Marijuana is abused among all racial groups, with no propensity for any one race.

Sex: Males consistently outnumber females in surveys of marijuana users.

Age: Adolescents and young adults are the most common group to abuse this substance; however, abuse may be observed relatively commonly in most age groups.

People who use marijuana may present either with acute effects of intoxication or with symptoms resulting from chronic use.

Onset of symptoms of marijuana intoxication occurs within a few minutes of smoking or within half an hour of oral ingestion. The duration of action usually is 6-12 hours; symptoms are most marked in the first 1-2 hours. The following symptoms may be prominent in acute intoxication:

Euphoria

Relaxation

Subjective feelings of well-being or grandiosity

Perceptual changes (including visual distortions)

Drowsiness and sluggishness

Diminished coordination

Paradoxical hyperalertness

A subjective sense of slowing of the passage of time

Increased appetite (the "munchies")

Although commonly misperceived as universally resulting in a relaxed and euphoric state, cannabis intoxication can produce a dysphoric reaction. Carefully examine patients for evidence of suicidality and homicidality, document presence or absence thereof, and manage as indicated.

Physical: Physical signs and symptoms reflect the effects of marijuana on multiple organ systems and can be classified according to the system involved.

Effects on central and peripheral nervous systems: Cannabis-induced cerebral atrophy or neuropsychological impairment remains a controversial diagnosis. Chronic effects of long-term marijuana use may be related to marijuana's significant fat solubility resulting in high blood levels of the drug after extended use. Marijuana-induced seizures have been described. Studies using simulated driving and flying situations have shown that the use of cannabis has a profound effect on estimations of time and distance and causes impairment of attention and short-term memory. These effects are still discernible 24-48 hours after use of the drug.

Effects on respiratory system: Cannabis smoke contains carcinogens similar to those found in tobacco smoke, and chronic heavy marijuana use may predispose people to chronic obstructive lung disease. Some studies indicate that pulmonary neoplasms are more common among habitual marijuana users; however, confounding by cigarette smoking limits the interpretability of some of these reports.

Effects on cardiovascular system: Acute intoxication may induce tachycardia and orthostatic hypotension.

Effects on reproductive system: Marijuana has been linked to infertility. In vitro studies have reported abnormal cell division and abnormal spermatogenesis resulting in decreased sperm counts; however, the effects of marijuana on human fertility remain unclear. In females, marijuana use may increase the number of anovulatory cycles. In males, marijuana use may cause a decrease in follicle-stimulating hormone, resulting in a decrease in testosterone production and, possibly, testicular atrophy.

Effects on gastrointestinal tract: Marijuana has known antinausea properties and the use of marijuana has been permitted for the treatment of nausea in some US states for this reason.

Ocular effects: Injected conjunctivae may occur.

Lab Studies: Cannabinoids can be detected in the urine for as many as 21 days after use in persons chronically using marijuana because these lipid soluble metabolites are slowly released from fat cells into the blood; however, 1-5 days is the normal urine-positive period. Blood samples may be used to measure quantitative levels of cannabinoids.

Treatment People who use marijuana and are suffering from biological, psychological, or social impairment from marijuana use should be evaluated and, if necessary, treated by a psychiatrist. The treatment of marijuana abuse follows the general principals of substance abuse, with particular attention paid to psychological and social aspects. Lifestyle changes, such as avoiding drug-related situations, may be encouraged. Identify and address low self-esteem, mood disorders, family problems, and other stresses. One-to-one therapy, group therapy, and even hospitalization may be necessary components of the treatment plan. (Patients with uncomplicated marijuana use in the absence of other psychiatric or medical problems are rarely hospitalized.)

Short-term, low-dose BZ treatment for acute intoxication has been used. Chronic psychosis associated with marijuana use may require antipsychotic treatment. Drug therapies that diminish cravings for marijuana or intoxicating effects from marijuana use currently are not available.

Treatment includes behavior therapy (aimed at reducing the chances of reexposure and establishing coping mechanisms to resist further use); family, group, and individual therapy; and periodic testing of urine to monitor abstinence.

Adolescent drug programs usually focus on promoting communication skills and age-appropriate behaviors.

School-based programs and peer-led groups may be useful in primary prevention of marijuana abuse.

Complications: Marijuana use may be complicated by comorbid substance use and medical problems as outlined.

Marijuana abuse may result in infants with low birth weights.

THC is soluble in breast milk and can be passed to infants.

Prognosis: As with other substance abuse conditions, relapse is common, and treatment may be necessary for multiple episodes.

Picture 1. Cannabis sativa

Picture 2. The major psychoactive component of marijuana is tetrahydrocannabinol (THC).