Supplemental Reading A: Who Needs Treatment? The Nature, Prevalence, and Consequences of Marijuana Dependence
Brief Marijuana Dependence Counseling (BMDC) is based on findings that show regular marijuana use can lead to a drug dependence syndrome characterized by impaired control over marijuana use, preoccupation with its use, tolerance of its effects, and recognizable withdrawal symptoms following abrupt discontinuation of its use. The syndrome typically develops over the course of years rather than months, with daily or near-daily marijuana smoking being the hallmark symptom.
The Nature of the Syndrome
A syndrome is a cluster of symptoms that signals the presence of an underlying disorder (see section IV of this manual for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition [DSM-IV] [American Psychiatric Association 1994] criteria for marijuana dependence). The marijuana dependence syndrome includes behavioral, psychological, and physiological symptoms that are typically reported by people who chronically smoke marijuana and who have difficulty controlling their use (Stephens and Roffman 1993). People who use marijuana daily develop tolerance for its subjective effects (e.g., feelings of being high) and cardiovascular effects (e.g., increased heart rate) (Compton et al. 1990; Wiesbeck et al. 1996). Some experience such difficulty in controlling their marijuana use that they continue to use despite adverse personal consequences of use (Stephens and Roffman 1993; Swift et al. 1998a, 1998b).
The relatively low intensity of physiological withdrawal symptoms resulting from heavy marijuana use may have contributed to marijuana’s not being viewed as dependence producing. However, studies have documented that people who use marijuana heavily and chronically may develop both physiological and psychological dependence and that cessation from use may produce a withdrawal syndrome broadly characterized by restlessness, irritability, mild agitation, insomnia, decreased appetite, sleep disturbance, anxiety, stomach pain, nausea, runny nose, sweating, and cramping (Crowley et al. 1998; Haney et al. 1999b; Wiesbeck et al. 1996). These symptoms commonly abate within a few days to 2 weeks of abstinence from marijuana.
Considerable evidence of a biological basis for marijuana dependence has accumulated since the identification of a specific cannabinoid receptor in the brain (Pertwee 1999) and the discovery of anandamide, a compound that binds to and activates the same receptor sites in the brain as delta-9-tetrahydrocannabinol (THC), the active ingredient in marijuana (Devane et al. 1992). Subsequently, researchers discovered a cannabinoid antagonist, a compound that blocks anandamide action in the brain (Rinaldi-Carmona et al. 1994). With increased knowledge of the neurochemical basis of marijuana’s reinforcing effects on brain systems, the biological basis of marijuana dependence is becoming better understood.
Prevalence
Marijuana is the most widely used illicit substance in the United States and is the third most widely used mood-altering substance after alcohol and tobacco. In 2003, more than 75 percent of illicit drug users (14.6 million people) smoked marijuana. For nearly 55 percent of illicit drug users, marijuana was the only substance they used (Substance Abuse and Mental Health Services Administration 2004). The proportion of young adults who use marijuana regularly has increased since the 1960s, and the age of initiation has declined (Hall et al. 1999). More risky patterns of smoking developed with the increased popularity of waterpipes or bongs, which permit the delivery of large doses of THC (Hall and Babor 2000). These conditions, combined with increased social tolerance of marijuana use, reduced penalties for possession, and the development of a substantial black market industry to distribute marijuana products, likely have increased the possibility that a substantial number of persons exposed to marijuana during their youth will continue to use the drug regularly into adulthood.
Epidemiological studies conducted in the last two decades have tracked trends in the prevalence of marijuana dependence. In the 1980s, the Epidemiological Catchment Area Study found that 4.4 percent of adults had been dependent on marijuana at some point in their lives (Anthony and Helzer 1991). About a decade later, the National Comorbidity Study estimated that 4.2 percent of the U.S. population met diagnostic criteria for marijuana dependence (Anthony et al. 1994). Whereas overall marijuana use was stable among the adult population in the 1990s, rates of dependence and abuse (as classified by the DSM-IV) increased significantly during the same period (Compton et al. 2004).
These studies indicate that marijuana dependence is one of the most prevalent substance use disorders in the United States, exceeded only by nicotine and alcohol dependence.