Schizophrenia has a wide range of symptoms, and not all symptoms may be present in all forms of schizophrenia. The signs and symptoms of schizophrenia are usually divided into two categories - positive and negative symptoms. A third category of cognitive symptoms is also included in some descriptions of the disease. Symptoms are further characterized by type. These types include motor, behavioral and mood disturbances. Symptoms can be positive or negative motor, behavioral, or cognitive disturbances.
Types of Symptoms
Positive symptoms are disorders of commission, meaning they are something that individuals do or think. Examples include hallucinations, delusions, and bizarre or disorganized behavior (Figure 1). Positive symptoms can also be categorized as "any behavior not seen in healthy people that correlates with loss of contact with reality". An example of a positive motor disturbance would be catatonic excitement, which is uncontrolled and aimless motor activity. Positive symptoms tend to be the easiest to recognize.
Hallucinations are one of the most noted symptoms and involve perceiving a sensory stimuli that no one else can. Most frequently, people with schizophrenia hear voices that tell them what to do, warn of danger, or talk to each other about the individual. Delusions can also be a very damaging symptom. They are false beliefs that are not of the culture of the individual, and are unchanging even after being proven incorrect.
Negative symptoms are disorders of omission, meaning they are things that the individual does not do. Examples include alogia (lack of speech), flat affect (lack of emotional response), anhedonia (inability to experience pleasure), asociality (lack of interest in social contact), avolition (lack of motivation) and apathy (lack of interest). Some individuals will experience a catatonic stupor. This is a state in which patients are immobile and mute, yet conscious. They may exhibit waxy flexibility, so one can move their limbs into postures and the patient will retain these postures, like a wax doll. In some cases, negative symptoms can be misinterpreted as depression or laziness.
Cognitive symptoms are the most harmful to the livelihood of the individual, as they prevent the individual from participating effectively in the workplace or in society. Cognitive symptoms are subtle differences in cognitive ability that are normally only discovered after neuropsychological tests are given. These include poor ability to absorb and act upon information (executive functioning), lack of attention, and an inability to utilize working memory.
Types of Disturbances
Motor disturbances include disorders of mobility, activity, and volition. People with schizophrenia can exhibit too little (negative) or too much (positive) movement. In addition to catatonic stupor and catatonic excitement outlined above, examples of motor disturbances include stereotypy (repeated, non-goal directed movement such as rocking), mannerisms (normal, goal-directed activities that appear to have social significance, but are either odd in appearance or out of context, such as repeatedly running one's hand through one's hair or grimacing), mitgehen (moving a limb in response to slight pressure, despite being told to resist the pressure), ecopraxia (the imitation of the movements of another person), and automatic obedience (carrying out simple commands in a robot-like fashion).
Disorders of behavior may involve deterioration of social functioning, such as social withdrawal, self-neglect or neglect of environment. Behavioral disorders may also involve socially inappropriate behaviors such as talking to oneself in public, obscene language, or inappropriate exposure.
Substance abuse is another disorder of behavior. Patients may abuse cigarettes, alcohol, or other substances. Substance abuse is associated with poor treatment compliance, and may be a form of "self-medication" for negative symptoms or medication effects.
Disorders of mood and affect include affective flattening, which is a reduced intensity of emotional expression and responsiveness that leaves patients indifferent and apathetic. Typically, one sees unchanging facial expression, decreased spontaneous movements, a lack of expressive gestures, poor eye contact, lack of vocal inflections, and slowed speech. Anhedonia, or the inability to experience pleasure, is also common, as is emotional emptiness. Patients may also exhibit inappropriate affect, such as laughing at a funeral.
Criteria for Diagnosis
The Diagnostic and Statistical Manual for Mental Disorders (DSM) defines schizophrenia as characterized by at least one psychotic episode, accompanied by associated functional decline. In addition to psychotic behavior, two or more additional symptoms must be present. These include delusions, hallucinations, disorganized speech, disorganized behavior or catatonia, or negative symptoms. Only one symptom may lead to diagnosis if the delusions or hallucinations are severe. These symptoms must persist for at least one month, although this criteria can be less if treatment is effectively provided. During the course of the disorder, the patient must show some signs of disturbance for at least 6 months. The disturbance must affect some aspect of the individual's functioning.