Tamiflu, made by Roche, has been associated with abnormal behaviour in teenagers, although no causal link has been found. Since 2004, a total of 15 young people have been injured or killed in incidents after taking the drug. In February and March two teenagers injured themselves by falling from buildings following treatment with Tamiflu.
Governments around the world have been stockpiling the drug in anticipation of an avian flu pandemic, as the drug is widely regarded as effective in treating H5N1 symptoms if caught early enough.
Roche has denied a link to suicide with the drug, and has pointed to new studies which have suggested that influenza itself could cause psychiatric symptoms such as hallucinations.