Marijuana has long been known to trigger attacks of mental illness, such as
bipolar (manic-depressive) psychosis and schizophrenia. This connection with
mental illness should make health care providers for terminally ill patients and
the patients themselves, who may already be suffering from some form of clinical
depression, weigh very carefully the pros and cons of adopting a therapeutic
course of marijuana.
In the short term, marijuana use impairs perception, judgment, thinking, memory,
and learning; memory defects may persist six weeks after last use. Mental
disorders connected with marijuana use merit their own category in the
Diagnostic and Statistical Manual of Mental Disorders (DSM) IV, published by the
American Psychiatric Association. These include Cannabis Intoxication
(consisting of impaired motor coordination, anxiety, impaired judgment,
sensation of slowed time, social withdrawal, and often includes perceptual
disturbances; Cannabis Intoxication Delirium (memory deficit, disorientation);
Cannabis Induced Psychotic Disorder, Delusions; Cannabis Induced Psychotic
Disorder, Hallucinations; and Cannabis Induced Anxiety Disorder.