A study by researchers from Stanford University and Brazil's Universidade Federal de Sao Paulo has found that a drug usually meant for the treatment of cognitive symptoms of Alzheimer's disease, may also aid in limiting sleep disturbances in patients.

It's long believed that Alzheimer's patients usually experience sleep-disordered breathing and this drug, called donepezil, may reduce these disturbances.

The researchers evaluated the effect of donepezil, on obstructive sleep apnea in 23 patients with Alzheimer disease in a randomised, double-blind design.

For the study, the patients were categorised into two groups: donepezil-treated (11) and placebo-treated (12), and polysomnography and cognitive evaluations were performed.

After the test period, it was found that patients treated with donepezil were found to have improved oxygen saturation, apnea-hypopnea index scores, and cognitive scores, and also increased sleep duration, as compared with those treated with placebo.

This study is published in the recent issue of the journal CHEST.

Marijuana does not boost risk of cancer

A study by researchers from New Zealand and Britain has revealed that smoking marijuana does not increase head and neck cancer risk.

For the study, the researchers scrutinised 75 cases of head and neck cancer. The findings revealed that the relative risk associated with smoking cannabis and head and neck cancer in marijuana users was the same (1.0) as in those who had never smoked cannabis.

These results differ from the relative risk associated with cigarette smoking and cancer at 2.1 and heavy alcohol intake at 5.7.

However, the authors said that a larger study is needed for clear understanding. The head and neck cancer is the fourth most common type of cancer with 500,000 new cases diagnosed each year globally.

The study is published in the March 2008 issue of Otolaryngology - Head and Neck Surgery.