Schizophrenia is a disorder in which patients have psychotic symptoms and social and/or occupational dysfunction that persists for at least 6 months.

Epidemiology

Schizophrenia affects I % of the population. The typical age of onset is the early 20s for men and the late 20s for women. Women are more likely to have a “first break” later in life; in fact, about one third of women have an onset of illness after age 30. Schizophrenia is diagnosed disproportionately among the lower socioeconomic classes; although theories exist for this finding, none have been substantiated.

Etiology

The etiology of schizophrenia is unknown. There is a clear inheritable component, but familial incidence is sporadic and schizophrenia does occur in families with no history of the disease. Schizophrenia is widely believed to have a neurobiological basis. The most notable theory is the dopamine hypothesis, which posits that schizophrenia is due to hyperactivity in brain dopaminergic pathways. This theory is consistent with the efficacy of antipsychotics (which block dopamine receptors) and the ability of drugs (such as cocaine or amphetamines) that stimulate dopaminergic activity to induce psychosis. Postmortem studies also have shown higher numbers of dopamine receptors in specific subcortical nuclei of schizophrenics than in normal brains. More recent studies have focused on structural and functional abnormalities through brain imaging of schizophrenics and control populations. No one finding or theory to date is adequate in explaining the etiology and pathogenesis of this complex disease.

Clinical Manifestations

History and Mental Status Examination
Schizophrenia is a disorder characterized by what have been termed positive and negative symptoms, a pattern of social and occupational deterioration, and persistence of the illness for at least 6 months. Positive symptoms are characterized by the presence of unusual thoughts, perceptions, and behaviors (e.g.,  hallucinations, delusions, agitation); negative symptoms are characterized by the absence of normal social and mental functions (e.g., lack of motivation, isolation, anergia, and poor self-care). The positive versus negative distinction was made in a nosologic attempt to identify subtypes of schizophrenia and because some medications seem to be more effective in treating negative symptoms. Clinically, patients often exhibit both positive and negative symptoms at the same time. Table 1-2 lists common positive and negative symptoms.

To make the diagnosis, two (or more) of the following criteria must be met: hallucinations, delusions, disorganized speech, grossly disorganized or catatonic (mute and/or posturing) behavior, or negative symptoms. There must also be social and/or occupational dysfunction. The patient must be ill for at least 6 months.

Patients with schizophrenia generally have a history of abnormal premorbid functioning. The prodrome of schizophrenia includes poor social skills, social withdrawal, and unusual (although not frankly delusional) thinking. Inquiring about the premorbid history may help to distinguish schizophrenia from a psychotic illness secondary to mania or drug ingestion.

Schizophrenics are at high risk for suicide.
Approximately one third will attempt suicide and 10% will complete suicide. Risk factors for suicide include male gender, age < 30 years, chronic course, prior depression, and recent hospital discharge.

DSM-IV recognizes five subtypes of schizophrenia: paranoid, disorganized, catatonic, undifferentiated, and residual. The subtypes of schizophrenia are useful as descriptors but have not been shown to be reliable or valid. Table 1-3 describes these subtypes.

Differential Diagnosis
The differential diagnosis of an acute psychotic episode is broad and challenging (Table 1-4). Once a medical or substance-related condition has been ruled out, the task is to differentiate schizophrenia from a schizo affective disorder, a mood disorder with psychotic features, a delusional disorder, or a personality disorder.

Management
Antipsychotic agents (also called neuroleptics) are primarily used in treatment. These medications are used to treat acute psychotic episodes and to maintain patients in remission or with chronic illness.

Combinations of several classes of medications are often prescribed in severe or refractory cases.
Psychosocial treatments, including stable reality- oriented psychotherapy, family support, psycho-education, social and vocational skills training, and attention to details of living situation (housing, roommates, daily activities), are critical to the long-term management of these patients. Poorer prognosis occurs with early onset, a history of head trauma, or comorbid substance abuse.