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Evidence-Based Practices:
Shaping Mental Health Services Toward Recovery
Co-Occurring Disorders:
Integrated Dual Disorders Treatment
Integrated Dual Disorders Treatment Workbook
Chapter 3: Cannabis
INTRODUCTION
Cannabis (also referred to as marijuana, pot, weed, herb, and hash) is a commonly used and abused substance throughout the U.S. and other countries. Many people feel relaxed and happy when using cannabis, though some experience anxiety or paranoia, and people with mental illness sometimes have severe psychotic reactions to the substance. This chapter presents a young man with schizoaffective disorder and cannabis dependence. The vignette and discussion illustrate some of the effects of cannabis on mental illness and some of the dilemmas that clinicians often face.
VIGNETTE
Corey is a 25-year-old man who has been diagnosed with schizoaffective disorder and cannabis dependence. He began smoking pot at the age of 15 with friends in high school. Corey says that marijuana always made him feel relaxed and comfortable.
At the age of 17, Corey experienced his first manic episode. He felt euphoric, powerful, and brilliant, without any need to sleep or eat. He described plans for a new fighter jet, which he was sure the US Air Force would buy to make him a famous millionaire. Corey was hospitalized during this episode, started on medication, and referred to the local community mental health center for follow-up treatment. Though he met a case manager and a psychiatrist, Corey wasn't convinced that he had a mental illness and didn't remember the symptoms he experienced while manic.
Since that first episode, Corey accepted prescriptions for medication, but did not take them regularly. He visited with his case manager every week and told her that he worried about people attempting to steal his plans for a new fighter jet. He continued to smoke marijuana daily and believed that he needed it to relax. He used to smoke with friends, but because he came to feel that they were out to get him, he smoked in his apartment by himself. Corey had several more hospitalizations for manic and psychotic symptoms. When his case manager suggested that there could be a connection between his use of marijuana, not taking medications, and ending up in the hospital, he disagreed and stated he would continue to smoke marijuana because "that is who I am."
Corey's functioning steadily deteriorated. After graduating from high school, Corey worked at a series of jobs that never lasted long, which he attributed to poor concentration and difficulty getting along with co-workers. He became isolated from family and friends. He was referred to a dual diagnosis assertive community treatment team.
For the first 2 years, team members used motivational interviewing techniques to get him interested in attending treatment and self help groups and to get him involved with a vocational specialist. He eventually chose to take medications regularly. He began holding a steady job at a book publishing company. He cut back on the frequency of his cannabis use and stated that he smoked pot occasionally on the weekends. He hadn't been hospitalized for over a year. He stopped bringing up the topic of fighter jets. After a total of 4 years with the team, he was still doing well. He graduated from the program and only saw a psychiatrist every 3 months.
BASIC INFORMATION ABOUT CANNABIS
Cannabis is the most commonly abused illegal substance in most of North America. Produced from the leaves, stems, and flowering tops of the plant Cannabis sativa, cannabis is widely grown and distributed. It is available in several forms, which vary widely in strength. The most common form is dried plant parts. Hashish, or hash, is the resin from the female plant flowers, and is usually stronger than the dried plant form. Hashish oil, made by distilling the plant in chemicals, is even more potent. Street marijuana is considerably more potent than in past years because of current growing and harvesting techniques.
Cannabis can be smoked or eaten. The active chemical, THC, is absorbed into the bloodstream and affects the brain, resulting in its characteristic effects. The THC is absorbed from the blood into fat cells and then slowly released back into the blood so it is removed from the body over days to weeks. Thus, the typical high ends within hours, but THC remains in the bloodstream at lower levels for a long time.
CANNABIS INTOXICATION AND SHORT-TERM EFFECTS ON MENTAL ILLNESS
Acute cannabis intoxication causes increased appetite, reduced motor performance (as in driving a car); reduced attention, concentration and memory; visual distortions and decreased recognition of visual stimuli; and a sense of time distortion. People who use cannabis report that it makes them feel anxious or paranoid, or conversely, happy, relaxed, and sleepy. High doses of the drug usually lead to paranoia and anxiety. The acute effects last approximately 3-4 hours.
Persons with mental illness who are intoxicated with cannabis may appear more paranoid or calm. They are often less able to participate in treatment or other activities due to reductions of attention and concentration. Cannabis use, even in small amounts, can precipitate acute psychotic episodes, which often require hospitalization and sometimes do not resolve quickly or easily. Because of cannabis users' perception that cannabis is calming and sleep-inducing, however, they are often unable to recognize the adverse effects of cannabis.
TOLERANCE AND WITHDRAWAL
There is some evidence that regular, heavy cannabis use produces tolerance, physiological dependence, and withdrawal symptoms. These have been somewhat controversial, in part because these effects can be less severe than those of other drugs and because cannabis is removed from the body slowly. After a regular user stops taking cannabis, the body takes about a month to remove all the cannabis. If a person does experience withdrawal symptoms, they typically include insomnia, anxiety, and irritability, as well as thoughts and dreams about cannabis use.
DETOXIFICATION FROM CANNABIS
Destabilization of the mental illness can occur during withdrawal from heavy cannabis use, though symptoms of withdrawal from cannabis are usually mild and not dangerous. Medical treatment is not necessary, but monitoring of mental illness and support for avoiding substance use are important.
LONG-TERM EFFECTS
Long-term cannabis use has negative effects on health. Cannabis smoke contains more tar and cancer-causing chemicals than tobacco smoke. Cannabis use is associated with lung damage and cancer. Cannabis is also linked with impaired immune function, heart problems, and changes in reproductive hormones.
Of great concern is the long-term effect of cannabis on mental illness. The vignette illustrates how long-term cannabis use in individuals with dual disorders is associated with poor outcomes (relapses, hospitalizations, declining functioning, and a lack of progress towards life goals). Corey's symptoms of mental illness have gradually worsened over time as he used cannabis heavily and refused mental health treatment. Heavy cannabis abuse impairs cognition (reducing attention, concentration, and memory), which impacts functioning at work, home, or school. Though Corey was interested in engineering and did well in school when he was young, he lost interest in pursuing education or work. The loss of interest and motivation may have been due to the cannabis, his mental illness, or, more likely, the combination.
MENTAL ILLNESS, SUBSTANCE USE DISORDER, OR BOTH?
Clients and families often notice that mental illness symptoms start when a person is using substances and they wonder whether substance abuse caused the mental disorder. Current research suggests that substance abuse does not cause severe mental illnesses like schizophrenia and bipolar disorder, but may precipitate episodes of illness in those who are vulnerable. Substance abuse can cause psychiatric symptoms during intoxication and withdrawal, but they typically go away when the person stops using. For people with severe mental illness, substance abuse is considered a biological stress that can precipitate mental illness. The symptoms continue, because the individual was already predisposed to having the mental illness by their biological make-up. Mental illness symptoms that have been present for months or years rarely resolve without treatment when substance abuse stops.
Recommended reading
The following article describes the psychiatric effects of cannabis use. Psychiatric Effects of Cannabis, Andrew Johns. British Journal of Psychiatry, 178,116-122, 2001.
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