Bristol-Myers Squibb (BMS) and Otsuka Pharmaceuticals spend almost twice on promotional activities than others in the industry but achieve less recognition, it has been alleged.

A study by Decision Resources found that in the atypical antipsychotics market, both companies spend about double the amount on marketing and promotion of Abilify (aripiprazole).

However, less than ten per cent of primary care physicians and psychiatrists mentioned either firm as a "top-of-mind" brand in this sector.

Instead, respondents cited AstraZeneca's Seroquel and Eli Lilly's Zyprexa as the manufacturers from which they receive the greatest amount of marketing material.

It is expected that the market for branded atypical antipsychotics will grow from $15.9 billion (7.96 billion pounds) in 2007 to $17.8 billion in 2011, Decision Resources reported.

"The atypical antipsychotics market has undergone huge shifts in market leadership that will continue over the forecast period," said Sandra Chow, an analyst at the research firm.

"In 2006, Janssen's Risperdal overtook Zyprexa's position as the sales leader for the seven major markets. Seroquel will become the seven-market sales leader in 2008," she added, before suggesting that further competition will be seen in generic form in future.

Last month saw Otsuka and BMS receive approval for Abilify for the treatment of bipolar disorder-associated episodes in paediatric patients.