Paliperidone extended-release injections (Invega Sustenna, Invega Trinza) are used to treat schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions). Paliperidone extended-release injection (Invega Sustenna) is also used alone or with other medications to treat schizoaffective disorder (a mental illness that causes both a loss of contact with reality and mood problems [depression or mania]). Paliperidone extended-release injection is in a class of medications called atypical antipsychotics.