TITUSVILLE, N.J. (AP) — Federal regulators have approved the antipsychotic Invega for use in treating schizoaffective disorder, according to Janssen, a unit of Johnson & Johnson. Titusville, N.J.-based Janssen said Friday the FDA approved the marketing of Invega extended-release tablets for use alone or in combination with mood stabilizers and antidepressants. Schizoaffective disorder causes symptoms similar to schizophrenia but also causes mania or depression. Invega was approved in December 2006 to treat schizophrenia. The drug is related to Risperdal, a former blockbuster antipsychotic that lost patent protection in 2008. Also on Friday, the FDA approved a once-monthly, injectable version of Invega to treat schizophrenia. Janssen markets Invega in the United States for New Brunswick, N.J.-based J&J.