Schizophrenia Diagnosis and DSM IV Schizophrenia Criteria
Many people are terrified at the possibility of a diagnosis of schizophrenia. Unfortunately, schizophrenia brings up images of “insanity,” violence, danger and even a death sentence. Fortunately, none of these things are true (see: Myths of Schizophrenia). Being diagnosed with schizophrenia is just like being diagnosed with any other illness. There are effective treatments and strategies for coping with a schizophrenia diagnosis.
How is Schizophrenia Diagnosed?
Schizophrenia is diagnosed, usually by a psychiatrist, with a mental status and history examination. There is no medical test for schizophrenia. However, the doctor may order a brain scan and run a complete blood count and thyroid function tests in order to rule out other possible physical causes of symptoms that may mimic the symptoms of schizophrenia.
The history of a patient is often useful when diagnosing schizophrenia. Diagnostic aids include information about:1
- Medical and psychiatric history of the patient and family
- Pregnancy details
- Travel history
- Medication and substance abuse
A mental status examination is also used to diagnose schizophrenia. Body language, behaviors and responses to questions are all part of the diagnosis process.
Diagnostic Symptoms of Schizophrenia
There are four types of schizophrenia symptoms and this is what the doctor will be looking for when considering a schizophrenia diagnosis.
- Positive symptoms such as hallucinations, delusions or inappropriate behavior (psychotic symptoms)
- Negative symptoms such as decrease in speech and emotional range or a loss of interest or drive (more on positive and negative schizophrenia symptoms)
- Cognitive symptoms such as memory, attention and organizational difficulties, as well as difficulty reading relationship cues
- Mood symptoms such as being cheerful or sad inappropriately
DSM IV Criteria for Schizophrenia
The diagnosis of schizophrenia is made using the criteria outlined in the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). The DSM-IV-TR criteria for schizophrenia include two or more of the following symptoms for a significant portion of time during a one-month period:2
- Delusions (false thoughts)
- Jumbled, incoherent or confused speech (disordered speech)
- Catatonic or incoherent behaviors
- Negative symptoms
Note that only one of the above is required if delusions are bizarre or if hallucinations consist of a voice keeping a running commentary on the person's behavior or thoughts, or two or more voices are conversing with each other.
In addition to the above, DSM-IV schizophrenia diagnostic criteria also requires:
- Social or work dysfunction
- Continuous signs for at least six months
A schizophrenia diagnosis must also rule out other medical, mood, psychotic and substance use disorders. Relationship to a developmental disorder (such as autism), if present, also must be taken into consideration.
Last Updated: 14 July 2016
Reviewed by Harry Croft, MD