Validity problems with the diagnosis remain and await further work in the fields of psychiatric genetics, neuroimaging, and cognitive science that includes the overlapping fields of cognitive, affective, and social neuroscience, which may change the way schizoaffective disorder is conceptualized and defined in future versions of the DSM and ICD. Comorbidities
Schizoaffective disorder shares a high level of comorbidity with other psychiatric disorders, specifically  anxiety disorders, depression, and bipolar disorder. Individuals with schizoaffective disorder are also often diagnosed with substance abuse disorder, usually relating to tobacco, marijuana, or alcohol. Health care providers indicate the importance of assessing for co-occurring substance use disorders, as multiple diagnoses not only potentially increase negative symptomology, but may also adversely affect the treatment of schizoaffective disorder. Types
One of three types of schizoaffective disorder may be noted in a diagnosis based on the mood component of the disorder:
Bipolar type, when the disturbance includes manic episodes, hypomania, or mixed episodes—major depressive episodes also typically occur;
Depressive type, when the disturbance includes major depressive episodes exclusively—that is, without manic, hypomanic, or mixed episodes. Mixed type, when the disturbance includes both manic and depressive symptoms, but psychotic symptoms exist separately from bipolar disorder. Problems with DSM-IV schizoaffective disorder
The American Psychiatric Associations DSM-IV criteria for schizoaffective disorder persisted for 19 years (1994–2013). Clinicians adequately trained in diagnosis used the schizoaffective diagnosis too often, largely because the criteria were poorly defined, ambiguous, and hard to use (or poorly operationalized).
Negative symptoms include alogia (lack of speech), blunted affect (reduced intensity of outward emotional expression), avolition (lack of motivation), and anhedonia (inability to experience pleasure). Negative symptoms can be more lasting and more debilitating than positive symptoms of psychosis. Mood symptoms are of mania, hypomania, mixed episode, or depression, and tend to be episodic rather than continuous. A mixed episode represents a combination of symptoms of mania and depression at the same time. Symptoms of mania include elevated or irritable mood, grandiosity (inflated self-esteem), agitation, risk-taking behavior, decreased need for sleep, poor concentration, rapid speech, and racing thoughts. Symptoms of depression include low mood, apathy, changes in appetite or weight, disturbances in sleep, changes in motor activity, fatigue, guilt or feelings of worthlessness, and suicidal thinking. DSM-5 states that if a patient only experiences psychotic symptoms during a mood episode, their diagnosis is Mood Disorder with Psychotic Features and not Schizophrenia or Schizoaffective Disorder. If the patient experiences psychotic symptoms without mood symptoms for longer than a two-week period, their diagnosis is either Schizophrenia or Schizoaffective Disorder. If mood disorder episodes are present for the majority and residual course of the illness and up until the diagnosis, the patient can be diagnosed with Schizoaffective Disorder. Causes
A combination of genetic and environmental factors are believed to play a role in the development of schizoaffective disorder.