Schizoaffective disorder is a condition that includes symptoms of psychosis along with symptoms of mania or depression. It is not certain how many people have this disorder, but it may affect between 0.2 percent and 0.5 percent of the population. In contrast, schizophrenia affects approximately 1 percent of the population. Since the two conditions are so similar, some experts suggest that 25 percent to 33 percent of people with schizophrenia may have schizoaffective disorder. The illness can linger for years or decades, but recovery can be seen with individuals displaying no symptoms for extended periods of time.
Criteria for an Accurate Diagnosis of Schizoaffective Disorder
Two or more psychotic symptoms
A concurrent major depressive, manic, or mixed episode
Delusions or hallucinations lasting at least fourteen days without prominent mood symptoms
Symptoms of a mood episode must be present for a substantial portion of the active and residual periods of illness
Drugs, medications, or medical condition must be ruled out as causes of the symptoms
Adapted from the DSM-IV.
It can be difficult for psychiatrists to establish the presence of both mood disorders and schizophrenia-like symptoms in a patient. It may require much observation to make a definitive diagnosis. The criteria are strict, and it is necessary to distinguish between the serious mood disorders of schizoaffective disorder and the disinterest and lack of pleasure that people with schizophrenia often develop.
Subtypes of Schizoaffective Disorder
Schizoaffective disorder is either bipolar type or depressive type. The bipolar type is applied if the patient experiences an episode of mania or a mixed episode of mania and depression at the same time. Major depressive episodes may also occur in this subtype. There are hints that younger adults are more prone this subtype than older adults. People with this subtype may tend to do better in the long run.
The presence of a major depressive episode with no prior history of a manic or mixed episode leads to a diagnosis of schizoaffective disorder, depressive type. Older patients may be affected more than young adults and women may be affected more than men. The increased number of women diagnosed with the depressive subtype probably explains the greater overall incidence of this disease among women.
Multiple studies indicate that children and siblings of people with schizoaffective disorder have an increased risk of developing schizophrenia. The incidence of mood disorders — depression and bipolar disorder — is also increased in relatives of people diagnosed with this psychotic disorder. This crossover between inherited susceptibility to schizophrenia, schizoaffective disorders, and mood disorders strengthens the argument that these diseases share at least some underlying root causes somewhere in the brain.