Comic actress Kirstie Alley and Kelly Preston, wife of actor John Travolta and an avid supporter of fellow Scientologist Tom Cruise, are set to join him in a battle against psychiatric drugs.

According to the New York Post, Alley and Preston compare psychiatric drugs such as Ritalin to cocaine and heroin. They have written a letter to the US Food and Drug Administration asking it to curb the medicines.

In the letter, Alley warns FDA: "Parents in particular have been misled about the effects of these drugs. They are highly addictive, and kids are using them more than street drugs to get high."

Tom Cruise recently had an on air clash with a TV show host over the issue where he went as far as to criticise Brooke Shields over taking drugs to deal with problems.