what is the difference between schizophrenia and psychosis
But not the same. Psychosis is a symptom, like fever is a symptom. Many conditions can have psychosis as a symptom, scores if not a100 different ones. Schizophrenia is a brain disease which has the symptom of psychosis at its'core.
Schizophrenia is a psychiatric disease characterized by psychosis as well as negative symptoms like lack of motivation and need for pleasure, lack of emotions and judgement, disorganisation of thought and behaviour. The exact causes for schizophrenia are not known. Psychosis can occur due to alcohol, drugs, medical conditions like hypothyroidism, mania, etc. Diagnosis of both is by exclusion of physical conditions, drug abuse, etc using blood tests, imaging procedures and DSM-IV criteria.