Diagnosed of schizophrenia require that person must meet the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM). When schizophrenia is suspected, doctor collects medical and psychiatric history, conduct a physical examination, and medical and psychological tests:
- Tests and screenings – These include lab test complete blood count (CBC), blood tests to get assessment of body chemistry and rule out conditions with similar symptoms. There must be screening for alcohol and drugs. Other possible investigation asked by doctor may be imaging studies such as an MRI or CT scan.
- Psychological evaluation – This includes assessment of mental status by observing appearance and demeanor and getting details about thoughts, moods, delusions, hallucinations, substance abuse, and indications of violence or suicide.
Diagnosis of schizophrenia involves ruling out other mental health disorders and substance abuse, medication or a medical condition. Person must have at least two of the following symptoms most of the time during a one-month period and some complaints over six months:
- Disorganized speech indicating disorganized thinking
- Extremely disorganized behavior
- Catatonic behavior
- Negative symptoms with reduced or lack of ability to function normally
At least one of the symptoms must be delusions, hallucinations or disorganized speech.