A US Food and Drug Administration advisory panel will meet later today to consider tightening up warning labels for attention-deficit hyperactivity disorder (ADHD) drugs following reports of psychosis, hallucinations and mania in children taking them.

FDA documents published ahead of the meeting suggest that these side effects can occur with all the currently-marketed drugs to treat ADHD, even at normal doses. The agency has reviewed around 90 clinical studies of the products, which include Novartis’ Ritalin (methylphenidate), Shire’s Adderall (mixed amphetamine salts), Eli Lilly’s Strattera (atomoxetine) and Johnson & Johnson’s Concerta (methylphenidate).

In the documents, FDA officials say patients and doctors must be made aware that the cases of psychosis and mania could be a drug-related side effect, while acknowledging there is no hard evidence yet to support a direct link. One cause for concern is the complete absence of cases in children taking placebo in the clinical trials reviewed.

Today’s meeting is just the latest in a series of reviews of the safety of ADHD drugs, which are seeing strong gains in popularity among both children and adults. Use of the products rose 19% among people aged 20 to 44 last year, to 1.7 million, while there was a 2% increase in usage among people aged 19 or younger to 3.3 million, according to just-published data from Medco Health Solutions.

However, use in younger children (aged two to 10) fell 5%, and this is thought to be related to press coverage of the ongoing debate into the products’ safety.

In February, an FDA panel recommended that black-box warnings be added to some of the products to indicate they may be linked to a higher risk of sudden death from cardiovascular side effects, although the agency said it would be unprecedented to put this level of warning notice on a product in the absence of definitive proof of causality. Adderall and Strattera were excluded from this recommendation.

The cardiovascular side effects are also due to be discussed at today’s meeting. And, tomorrow, the panel will review the marketing application for Cephalon’s ADHD drug candidate Sparlon (modafinil).