Various mental disorders and medical conditions must be considered in the differential diagnosis of schizophreniform disorder.

These include psychotic disorder due to another medical condition or its treatment; delirium or major neurocognitive disorder or major neurocognitive disorder; substance/medication induced psychotic disorder or delirium; major depressive or bipolar disorder with psychotic features; schizoaffective disorder; other specified or unspecified bipolar and related disorder; major depressive or bipolar disorder with catatonic features; schizophrenia; delusional disorder; other specified or unspecified schizophrenia spectrum and other psychotic disorder; schizotypal, schizoid, or paranoid personality disorders; autism spectrum disorder; disorders presenting in childhood with disorganized speech; attention-deficit/hyperactivity disorder; obsessive compulsive disorder; posttraumatic stress disorder; and traumatic brain injury.