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Prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people

BMJ 2004; 330 doi: (Published 30 December 2004) Cite this as: BMJ 2004;330:11

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Cannabis and copper and zinc upsets increase the risk of psychosis?

A clue why the risk of cannabis-psychosis is four times more likely in young people with predisposing factors, may be found in the results of animal studies of the interactions with copper and zinc and cannabis.1 Copper potentiated the barbiturate hypnosis-potentiating activity of cannabis.2 Single doses of copper partially inhibited tolerance to barbiturate hypnosis-potentiation activity and markedly delayed the development of tolerance to hypothermic activity of cannabis for one to two weeks. Many patients prone to mental instability have difficulty in maintaining a normal copper/zinc balance.

Zinc deficiency is extremely common and is increased with smoking tobacco and drinking alcohol. Men have lower zinc levels than women and need extra zinc during growth. Menstruating females have higher copper levels than males. If women also use progesterone contraceptives or menopausal hormones, high monoamine oxidase levels and even higher than usual copper levels increase the risk of mental illnesses and suicide attempts.3,4 Infections also increase copper levels. Copper stores may become depleted and copper deficiency impairs Cu/Zn superoxide dismutase activities.

These important homeostatic imbalances increase adverse reactions to foods and chemicals. Zinc and copper deficiency or high copper levels can also block essential fatty acid pathways, causing both omega-6 and omega-3 deficiencies, and also vitamin B group deficiencies, which further increase the risk of psychosis. Monitored nutritional supplementation with 1mg doses of copper in the morning and 30 mg doses of zinc in the evening for two or three weeks can give a rapid improvement in many conditions. In particular, the resolution of mental or neurological illnesses can be very dramatic.

1 Henquet C, Krabbendam L, Spauwen J, et al. Prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people BMJ 2004; 0: bmj.38267.664086.63v1

2 Singh PP, Das PK. Studies on the interactions of copper and cannabis. Psychopharmacology (Berl). 1978 ;56 : 309-16.

3 Grant ECG. The Pill, Hormone Replacement Therapy, Vascular and Mood Over-reactivity, and Mineral Imbalance J Nutr Environ Med 1998; 8: 105- 116.

4 Price EH. Increased Risk of Mental Illness and Suicide in Oral Contraceptive and Hormone Replacement Therapy Studies 1998; 8: 121-127.

Competing interests: None declared

Competing interests: No competing interests

05 December 2004
Ellen C G Grant
physician and medical gynaecologist
20 Coombe Ridings, Kingston-upon-Thames, KT2 7JU, UK