A long-term research study (published in 2003) of more than 50,000 Swedish military conscripts suggests that early cigarette smoking may provide a shield against schizophrenia. After a variety of other possible influences were accounted for, men who smoked cigarettes at the time of conscription (ages 18-20) were less likely to be diagnosed with schizophrenia during the following 27 years.

The more they smoked, the lower the chance of developing schizophrenia. Each increase of one half pack per day reduced the risk by about 10%, up to 1 and 1/2 packs per day. The association did not hold in the first five years after conscription, but some men diagnosed during that time may already have been suffering from unrecognized early symptoms in late adolescence.

These results are, suggest the researchers, "consistent with animal models showing both neuroprotective effects of nicotine and differential release of prefrontal dopamine in response to nicotine." Similarly - in other studies researchers have found that in parkinsons disease studies that "smoking may induce a biological protection against nigral neuronal damage".

IMPORTANT: Researchers are NOT suggesting smoking for people as a means to prevent schizophrenia - because of the well-known and deadly Lung Cancer and Emphysema that is caused by smoking. As the researchers noted in their own report "The harmful effects of cigarette smoking vastly outweigh any possible benefits"

Possibly Helpful Actions: It seems possible that people with very high risk of schizophrenia (due to family history - e.g. mother or father had schizophrenia, or an identical twin brother or sister with schizophrenia, or multiple people in family have had schizophrenia) might benefit from the use of medicinal nicotine products such as nicotine gum or nicotine losenges, nicotine patches, etc. - as a strategy for potentially lowering their schizophrenia risk. Medicinal nicotine patches are not addictive, researchers say, so this does not seem to be an issue.

A recent article in the "Harvard Health Letter" (May, 2005) suggests that " Most experts say nicotine itself does not cause cancer. It's addictive,...but ... other substances in tobacco smoke (polycyclic aromatic hydrocarbons, tobacco-specific nitrosamine) that cause DNA damage and therefore cancer.". That same issue of Harvard Health Letter noted the "good safety record of the patch and other nicotine replacements, while noting that there has been some legitimate concern about the development of insulin resistance."

Supporting and Related Research:

• Schizophrenia and Smoking - Special Report
• Nicotine for Alzheimers and Schizophrenia? (December, 2005)
• Investigating the association between cigarette smoking and schizophrenia in a cohort study (2003)
• Schizophrenia, Smoking and Nicotine Resources, Research and Information