Schizoaffective disorder is a psychiatric condition characterized by a set of symptoms that combines features of schizophrenia with features of depression, mania, or some other form of mood disorder. Compared to most other mental illnesses, doctors know relatively little about schizoaffective illness. This is true, in part, because of the complex combination of symptoms that can appear in any given affected individual. Women develop schizoaffective disorder more frequently than men, and have unique pregnancy-related risks for the condition. In addition, women tend to develop a particular form of the illness called depressive-type schizoaffective disorder. Schizoaffective Disorder Basics Doctors typically make a diagnosis of schizoaffective disorder in people who have schizophrenic symptoms and mood disorder symptoms, but don't fully meet the guidelines required for a strict diagnosis of either schizophrenia or a specific mood disorder. Symptoms of schizophrenia found in people with the disorder include visual, auditory (sound-based), tactile (touch-based), or odor-based hallucinations, as well as delusional forms of thought that focus on things such as persecution fantasies or other demonstrably false beliefs. Additional symptoms of schizoaffective disorder vary from person to person, the Mayo Clinic explains. Most people with the illness develop depressive-type schizoaffective disorder or a second condition called bipolar-type schizoaffective disorder. In addition to schizophrenic symptoms, people with the depressive form of the illness develop symptoms of depression such as sadness, hopelessness, and suicidal thinking. People with the bipolar form of the illness develop some depressive symptoms, as well as manic or hyperactive moods and rapid surges in physical energy. Because of the ways in which these symptoms can interact in any given person, doctors sometimes have a hard time telling the difference between schizophrenia, schizoaffective disorder, bipolar disorder, and depression. While no one knows exactly what causes schizoaffective disorder, it probably has a partially genetic basis similar to the genetic origins of schizophrenia. Abnormal levels of vital brain chemicals called norepinephrine, serotonin, and dopamine also appear to help trigger the condition. In addition, people with schizoaffective disorder tend to have unusually undersized versions of key brain structures, such as the thalamus and hippocampus, which help control mood and behavior. Frequency in Women As stated previously, schizoaffective disorder is not a particularly well-understood or easily identified mental illness. For this reason, no one knows for sure how many people have some form of the disorder. However, most mental health researchers believe that roughly 0.3 to 1 percent of all Americans will develop schizoaffective symptoms at some point in their lifetime. Children rarely develop the disorder. Among adults, men typically develop schizoaffective symptoms earlier in life than women. Despite the relatively late onset of illness, women ultimately develop schizoaffective disorder more frequently than men. Most researchers believe that women's tendency to develop depressive illnesses throughout the course of adulthood partly explains this gender-based gap. Pregnancy-Related Risks Pregnancy is well known for its ability to increase women's physical and mental stress levels for extended periods of time. Typically, people with schizoaffective disorder react poorly to the effects of mental stress. As a result of the interaction between these two factors, women with schizoaffective disorder have particularly high risks for stress-related mental health complications both during the course of a pregnancy and in the period following a pregnancy. Most commonly, complications during pregnancy manifest as a psychotic break with reality; complications following pregnancy tend to manifest as post-partum depression. Considerations Apart from depressive-type and bipolar-type forms of the illness, some people with schizoaffective disorder develop a mixed form of the illness that features both depressive and bipolar symptoms in equal measure. In some cases, people develop schizoaffective disorder in the aftermath of a clear triggering event or situation; in other cases, the condition appears unexpectedly without any clear starting point. Generally speaking, doctors have an easier time identifying and treating forms of the illness that have a known point of origin. People with pre-existing cases of certain personality disorders-including borderline personality disorder, schizoid personality disorder, paranoid personality disorder and schizotypal personality disorder-may have increased risks for the onset of schizoaffective disorder. In part, these risks appear to stem from personality disorders' tendency to produce a chronic inability to cope well with common life stresses; in turn, this lack of coping skills can lead to psychotic responses to the ongoing effects of stress.