Schizophrenia is a brain disorder that distorts the way a person thinks, acts, expresses emotions, perceives reality, and relates to others. 
Depression is an illness that is marked by feelings of sadness, worthlessness, or hopelessness, as well as problems concentrating and remembering details. 
Bipolar disorder includes cycling mood changes, such as severe highs (mania) and lows (depression).
Schizoaffective disorder can affect all of your life, including work or school, family, friends, and other relationships. Most people who have it go through times called relapses, when their symptoms surface.
Although there is no cure, there are treatments that can manage symptoms.

Symptoms

The symptoms of schizoaffective disorder may vary greatly from one person to the next and may be mild or severe. They may include:
  • Poor appetite
  • Weight loss or gain
  • Changes in sleeping patterns (sleeping very little or a lot)
  • Agitation (being very restless)
  • Lack of energy
  • Loss of interest in usual activities
  • Feelings of worthlessness or hopelessness
  • Guilt or self-blame
  • Trouble with thinking or concentration
  • Thoughts of death or suicide
Mania
  • Being more active than usual, including at work, in your social life, or sexually
  • Talking more or faster
  • Rapid or racing thoughts
  • Little need for sleep
  • Agitation
  • Being full of yourself
  • Being easily distracted
  • Self-destructive or dangerous behavior (such as going on spending sprees, driving recklessly, or having risky sex)
  • Delusions (strange beliefs that the person refuses to give up, even when they get the facts)
  • Hallucinations (sensing things that aren't real, such as hearing voices)
  • Disorganized thinking
  • Odd or unusual behavior
  • Slow movements or not moving at all
  • Lack of emotion in facial expression and speech
  • Poor motivation
  • Problems with speech and communication

Causes

Scientists don’t know the exact cause of schizoaffective disorder. Things that may be involved include:
Genetics (heredity): Someone may inherit a tendency to develop schizoaffective disorder from their parents.
Brain  structure and function: People with schizophrenia and mood disorders may have problems with brain circuits that manage mood and thinking.
Environment: Environmental things -- such as a viral infection, bad relationships, or highly stressful situations -- may trigger schizoaffective disorder in people who are at risk for it. How that happens isn’t clear.
Schizoaffective disorder usually begins in the late teen years or early adulthood, often between ages 16 and 30. It seems to happen slightly more often in women than in men. It's rare in children. 
Because people with schizoaffective disorder have a combination of symptoms reflecting two separate mental illnesses, it’s often misdiagnosed. Some people may be misdiagnosed as having schizophrenia, and others may be misdiagnosed with a mood disorder. As a result, it’s hard to determine exactly how many people actually have schizoaffective disorder. It’s probably less common than either schizophrenia or mood disorders alone.

Diagnosis

If a doctor thinks someone has symptoms of schizoaffective disorder, they’ll want to know everything about that person’s medical history -- both physical and mental. They may also give that person a physical exam.
There are no laboratory tests to specifically diagnose schizoaffective disorder. So doctors may use various tests -- such as brain imaging (like MRI scans) and blood tests -- to make sure that a physical illness isn’t the reason for the symptoms.
If the doctor finds no physical cause, he may refer the person to a psychiatrist or psychologist. These mental health professionals are trained to diagnose and treat mental illnesses. They use specially designed interview and assessment tools to evaluate a person for a psychotic disorder.
In order to diagnose someone with schizoaffective disorder, the person must have periods of uninterrupted illness and, at some point, an episode of mania, major depression, or a mix of both, while also having symptoms of schizophrenia. The person must also have had a period of at least two weeks of psychotic symptoms without the mood (depression or bipolar) symptoms.

Treatment

Treatment is very important. Research shows that it’s effective in keeping symptoms under control and helping the person manage the condition and get along better in their everyday life.
Most people will get:
Medication : Some of the medicine a person needs depends on whether they have depression or bipolar disorder, along with schizophrenia.  The main medications that doctors prescribe for psychotic symptoms such as delusions, hallucinations, and disordered thinking are called antipsychotics.  All antipsychotic drugs likely have value in the treatment of schizoaffective disorder, but paliperidone extended release (Invega) is the only drug that the FDA has approved to treat schizoaffective disorder. For mood-related symptoms, someone may take an antidepressant medication or a mood stabilizer such as lithium. They often will also take an antipsychotic medication.
Psychotherapy : The goal of this type of counseling is to help the person learn about their illness, set goals, and manage everyday problems related to the disorder. Family therapy can help families become more effective in relating to and helping a loved one who has schizoaffective disorder.
Skills training: This generally focuses on work and social skills, grooming and self-care, and other day-to-day activities, including money and home management.
Hospitalization : Most people with schizoaffective disorder live at home. But if someone has severe symptoms or is in danger of hurting themselves or others, they may need to stay in a hospital until they’re better.
Treatment is very important. Research shows that it’s effective in keeping symptoms under control and helping the person manage the condition and get along better in their everyday life.

Can You Prevent Schizoaffective Disorder?

No. But if someone gets diagnosed and starts treatment ASAP, it can help a person avoid or reduce frequent relapses and hospitalizations and help decrease the disruption to the person's life, family, and friendships.