Marijuana causes many mental disorders, including acute toxic psychosis, panic attacks, flashbacks, delusions, depersonalization, hallucinations, paranoia, depression, and "uncontrollable feelings of aggression." (1)

Increased aggressive behavior after smoking marijuana has been reported in inner city males. (2)

Marijuana has long been known to trigger attacks of mental illness, such as bipolar (manic-depressive) psychosis and schizophrenia. It has been shown that marijuana users are six times more likely to develop schizophrenia than are non-users. (3)

Marijuana use is associated with the development of Amotivational Syndrome. (4)

"Often the relationship of impairments and symptoms to marijuana use becomes evident only when the user is persuaded to stop, shows clear-cut improvement in mood and behavior, and describes a feeling of coming out of a fog." (5)

Marijuana impairs perception, judgment, thinking, memory, and learning. Memory defects may persist six weeks after last use. (6)

Mental disorders caused by marijuana (cannabis) listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV, published by the American Psychiatric Association May 1994 include: Cannabis Dependence; Cannabis Abuse; Cannabis Intoxication (impaired motor coordination, anxiety, impaired judgment, sensation of slowed time, social withdrawal), often includes perceptual disturbances; Cannabis Intoxication Delirium (memory deficit, disorientation); Cannabis Induced Psychotic Disorder, Delusions; Cannabis Induced Psychotic Disorder, Hallucinations; Cannabis Induced Anxiety Disorder; other Cannabis-Related Disorders. Marijuana causes both dependence and addiction. "Marijuana is an addictive drug... Addictive use is defined by compulsive, repeated use in spite of adverse consequences. Marijuanas effects include tolerance, leading to dependence, and then inability to cease use." (7)

In many parts of the country, there are more people admitted to drug treatment centers because of marijuana addiction than heroin addiction. (8)

A withdrawal syndrome occurs, consisting of "anxiety, depression, sleep and appetite disturbances, irritability, tremors, diaphoresis, nausea, muscle convulsions, and restlessness." (9)

Since marijuana impairs coordination, perception, and judgment, it is the cause of many accidents. A study of 1023 trauma victims revealed that marijuana had been used by 34.7%; alcohol had been used by 33.5%. (10)

This is similar to a 36.8% incidence of marijuana use reported in fatally injured drivers in California. (11)

A study of 182 fatal truck accidents revealed that 12.8% of the drivers had used marijuana, 12.5% alcohol, 8.5% cocaine, 7.9% stimulants. (12)

A roadside study of reckless drivers not believed to be impaired by alcohol found that 45% tested positive for marijuana. (13)

The effects of marijuana, which is fat-soluble, persist much longer than the effects of alcohol, which is water soluble. An experiment on pilots, using a computerized flight simulator, showed that their ability to land a plane was still impaired 24 hours after smoking a single marijuana cigarette. (14)

The use of marijuana during pregnancy is associated with babies of low birth weight. (15)

Also, there is evidence that such infants will show intellectual impairment a decade or more later. (16)

Children exposed to marijuana prenatally have increased behavioral problems; they have decreased visual perception, language comprehension, attention span and memory. (17)

Babies born to mothers who use marijuana during pregnancy have an eleven-fold increase in nonlymphoblastic leukemia. (18)

In males, marijuana diminishes testosterone production and lowers sperm counts. In females, marijuana disrupts hormone cycles. (19)

Studies have shown that marijuana is mutagenic and impairs DNA synthesis. (20)

Marijuana smoke produces airway injury, acute and chronic bronchitis, lung inflammation, and decreased pulmonary defenses against infection. Smoking one marijuana cigarette leads to airway deposition of four times as much cancer-causing tar as does tobacco smoke. (21)

Recently, there have been cases of cancer reported in young marijuana smokers, including cancer of the mouth, tongue, larynx, jaw, head, neck, and lungs. (22)

Marijuana causes impairment of the white blood cells which fight infections. (23)

Marijuana use decreases resistance to diseases such as herpes. (24)

Marijuana smokers have increased outpatient visits for respiratory illnesses, accidents, and other illnesses. (25)

The use of marijuana tends to lead to the use of other drugs. 20% of persons who use marijuana 3-10 times go on to use cocaine; 75% of persons who use marijuana 100 or more times go on to use cocaine. (26)

Non-marijuana users virtually never become cocaine users. In Alaska, when marijuana use was decriminalized, use by Alaskan youth of both marijuana and cocaine became the highest in the nation. The National Survey of High School Seniors showed that whereas nationally 17% of seniors had used marijuana in the past month, the Alaskan rate was 45%. The Alaskans then sensibly recriminalized marijuana use in 1990.

1. Schwartz RH. Pediatric Clinics of North America 34:305-317, 1987.

2. Cherek DR et al. Psychopharmacology 111:163-168, 1993.

3. Andreasson S et al. Lancet 2:1483-1485, 1987.

4. Schwartz RH, op.cit.

5. Jaffe JH. Drug Dependence. In Kaplan HI, Saddock BJ eds, Comprehensive Textbook of Psychiatry, Baltimore: Williams & Wilkins, 1989.

6. Schwartz RH et al. Am J Dis Child 143:1214-1219, 1989.

7. Gold MS. Marijuana, NY:Plenum Medical Book Co., p. 227, 1989.

8. Office of National Drug Control Policy. Pulse Check, December 1994.

9. Gold MS. op. cit. p. 103.

10. Soderstrom CA et al. Archives of Surg 123:733-737, 1988.

11. Williams AF et al. Public Health Report 100:19-25, 1985.

12. Department of Transportation. National Transportation Safety Board Report, Washington DC, February 5, 1990.

13. Brookoff D et al. New Eng J Med 331:518-522, 1994.

14. Leirer VO et al. Aviat Space Environ Med 62:221-227, 1991.

15. Zuckerman B et al. New Eng J Med 320:762-768, 1989.

16. Shalala DE. Say No to Legalization of Marijuana. The Wall Street Journal, August 18, 1995.

17. Fried PA. Life Sciences 56:2159-2168, 1995.

18. Robison LL et al. Cancer 63:1904-1910, 1989.

19. Gold MS. op. cit. p. 69-71.

20. Nahas G et al. Med J Austr 156:495-497, 1992.

21.Tashkin DP. West J Med 158:635-637, 1993.

22. Donald PJ Otolaryn Head & Neck Surg 94:517-521, 1986. Ferguson RP et al. JAMA 261:41-42, 1989. Taylor FM. South Med J 81:1213-1216, 1988. Donald PJ. Adv Exp Med Bio 288:33-46, 1991.

23. Spector S et al. Adv Exp Med Bio 288:47-56, 1991. Djeu J et al. Adv Exp Med Bio 288: 57-62, 1991. Watzl B et al. Adv Exp Med Bio 288: 63-70, 1991. Cabral GA et al. Adv Exp Med Bio 288: 93-105, 1991.

24. Cabral GA et al. Proc Soc Exp Bio Med 182:181-186, 1986.

25. Polen MR et al West J Med 158:596-601, 1993.

26.Kleber HD. J Clin Psych 49:2(Suppl), p. 3-6, 1988.