U.S. regulators on Wednesday approved a new once-a-day treatment for schizophrenia derived from the active ingredient in Johnson & Johnson’s blockbuster schizophrenia treatment Risperdal.

The pill, called Invega, is the first new schizophrenia treatment to win U.S. Food and Drug Administration approval since 2003, according to J&J.

Schizophrenia is a chronic, disabling mental disorder that affects more than 2 million Americans. Symptoms include hallucinations, delusions, disordered thinking, movement disorders, social withdrawal and cognitive deficits, such difficulty with perception, memory or abstract thinking.

The new treatment is designed to deliver paliperidone - the active ingredient in Risperdal - through a technology that allows the drug to remain in the body over a longer period of time.

“Schizophrenia can be a devastating illness requiring lifelong medication and professional counseling,” said Dr. Douglas Throckmorton, deputy director of the FDA’s Center for Drug Evaluation and Research.

“Today’s approval adds to the treatment options for patients with this condition,” he said in a statement announcing the approval.

Wall Street analysts see the approval as key to J&J’s drug portfolio. JP Morgan analyst Michael Weinstein has called Invega “the most important drug in J&J’s pipeline.”

In a note to clients last month, Weinstein said a year-end approval would give J&J 18 months to market the drug before the start of generic competition for its older drug Risperdal.

Risperdal and the injectable long-acting version Risperdal Consta had combined sales of more than $1 billion in the most recent quarter.

J&J will market Invega in the United States by the company’s Janssen LP unit.

Invega is part of a class of drugs known as atypical antipsychotics. Introduced in the 1990s, the drugs now account for some $10 billion in U.S. sales.