Symptoms of schizoaffective disorder are complex and without treatment they are disabling.
Janssen Scientific Affairs director of Clinical Development Dong-Jing Fu said: "Schizoaffective disorder is a difficult-to-treat disease.
"Approval of Invega Sustenna to manage the mood as well as the psychosis that define the condition has the potential to change the lives of the 750,000 adult Americans who suffer from it."
The FDA approved these sNDAs under priority review, which is a designation for drugs that, if approved, would provide improvement in the treatment of serious conditions.
The FDA approval is based on results from a 15-month period of a long-term maintenance trial measuring ability to delay relapse in schizoaffective disorder.
The data showed that treatment with Invega Sustenna resulted in a statistically significant delay in relapse due to mood and psychotic symptoms of schizoaffective disorder compared to placebo.
The company said that Invega Sustenna is the first and only FDA-approved once-monthly medicine to treat schizoaffective disorder as monotherapy.