No one symptom positively identifies schizophrenia. All of the symptoms of this illness can also be found in other brain disorders. For example psychotic symptoms may be caused by the use of drugs, may be present in individuals with Alzheimer's Disease, or may be characteristics of a manic episode in bipolar disorder. However, when a doctor sees the symptoms of schizophrenia and carefully asseses the history and the course of the illness over six months, he or she can almost always make a correct diagnosis.
The symptoms of schizophrenia are generally divided into three categories, including positive, disorganized and negative symptoms.
Positive Symptoms, or "psychotic" symptoms, include delusions and hallucinations because the patient has lost touch with reality in certain important ways. "Positive" as used here does not mean "good." Rather, it refers to having overt symptoms that should not be there. Delusions cause the patient to believe that people are reading their thoughts or plotting against them, that others are secretly monitoring and threatening them, or that they can control other people's minds. Hallucinations cause people to hear or see things that are not there.
Disorganized Symptoms include confused thinking and speech, and behavior that does not make sense. For example, people with schizophrenia sometimes have trouble communicating in coherent sentences or carrying on conversations with others; move more slowly, repeat rhythmic gestures or make movements such as walking in circles or pacing; and have difficulty making sense of everyday sights, sounds and feelings.
Negative Symptoms include emotional flatness or lack of expression, an inability to start and follow through with activities, speech that is brief and lacks content, and a lack of pleasure or interest in life. "Negative" does not, therefore, refer to a person's attitude, but to a lack of certain characteristics that should be there.
Schizophrenia is also associated with changes in cognition. These changes affect the ability to remember and to plan for achieving goals. Also, attention and motivation are diminished. The cognitive problems of schizophrenia may be important factors in long term outcome.
Schizophrenia also affects mood. Many individuals affected with schizophrenia become depressed, and some individuals also have apparent mood swings and even bipolar-like states. When mood instability is a major feature of the illness, it is called, schizoaffective disorder, meaning that elements of schizophrenia and mood disorders are prominently displayed by the same individual. It is not clear whether schizoaffective disorder is a distinct condition or simply a subtype of schizophrenia.
