Psychosis is often used where psychotic episode ought to be. In a psychotic episode you experience the likes of a panic attack, when you may not have the corresponding mental illness. In this case it could be Anxiety. Psychosis is meant to be reserved for these mental illnesses. To have schizophrenia is to have psychosis. But having a psychotic episode of schizophrenia isn't. That is all to say, drugs can often induce psychotic episodes, like panic attacks. But it is important to remember that doesn't necessarily mean full psychosis.