Schizophrenia Diagnosis

  • Diagnosis

    Schizophrenia is a chronic and debilitating mental illness that affects up to 1% of the general population. Schizophrenia is a severe and disabling brain disorder that usually begins in late adolescence or early adulthood, and often lasts in one form or another throughout life. The symptoms of schizophrenia are diverse, and affect many different aspects of brain functioning. You may experience difficulty distinguishing reality from fantasy (psychosis), find your mental quickness and emotions to be dulled, and may have difficulty communicating. There are five subtypes of schizophrenia: paranoid, disorganized, catatonic, residual, or undifferentiated. The symptoms you have will depend on your subtype of schizophrenia.

    The exact causes for schizophrenia are not yet known. Both genetic and non-genetic (environmental) factors are thought to be involved. Having one biological parent with schizophrenia increases your risk of having the disease yourself from 1% to about 10%. Having to two biological parents with schizophrenia increases your risk to almost 50%. Interestingly, this remains true even if you are adopted at birth and raised by parents who are not mentally ill, suggesting that genetic factors play a more important role than environment. Multiple genes are likely to be involved in causing the disease.

    Environmental factors that have been implicated in the development of schizophrenia include gestational and birth complications such as incompatible mother/fetus red blood cell types (Rh factor incompatibility), prenatal exposure to influenza during the second trimester, and prenatal malnutrition.

    Studies have revealed that there are structural and functional differences in the brains of people with schizophrenia. It is still unclear whether such abnormalities are the cause or result of the disease Figure 01. The abnormalities of schizophrenia affect different parts of the brain, including structures that affect the emotions (prefrontal cerebral cortex, hippocampus, and related limbic structures). Damage to these areas may result from an insufficient oxygen supply (hypoxia) during critical stages of brain development. Biochemical abnormalities are also thought to play a role in schizophrenia.

    Click to enlarge: Areas of abnormalities found to be more common in the brains of people with schizophrenia.

    Figure 01. Areas of abnormalities found to be more common in the brains of people with schizophrenia.

    The symptoms of schizophrenia are highly variable Table 01. If you have schizophrenia, you may behave differently at different times, and experience psychotic episodes that come and go. Symptoms generally appear in men in their teens or early twenties, whereas women generally experience their first symptoms in their twenties or thirties.

    Symptoms of schizophrenia are classified as being positive or negative. Positive symptoms are defined as those that would not occur normally in the general population, and include such things as psychosis, hallucinations, and delusions. Psychosis is a state of being out of touch with reality, or the inability to separate reality from fantasy. Hallucinations occur when you sense something that does not exist (such as hearing imaginary voices). Delusions are beliefs that are not based in reality, such as feelings of being persecuted or conspired against.

    Negative symptoms are defined as a lack of behaviors that would normally occur in society. Negative symptoms include dulled emotions, reduced speech, and extreme lack of motivation and drive. Negative symptoms are among the most common and debilitating symptoms of schizophrenia. These symptoms are most often associated with a poor long-term outcome and poor response to medication.

    Table 1.  Symptoms of Schizophrenia

    Positive symptoms
    Delusions Hallucinations Bizarre speech/thought processes
    Paranoid Auditory Loosening of associations or derailed thinking (when your thought processes go "off the track")
    Grandiose Visual
    Religious Olfactory
    Somatic Somatic
    Sexual Tactile
    Referential (thinking that things,like what you see and hear on the TVor radio refer to you specifically)
    Negative symptoms
    ?Poverty of speech Social isolation ?Other
    Reduced amount of speech Disinterest Self?neglect
    Reduced content Poor rapport Lack of interests
    Reduced tone Lack of motivation
    Cognitive deficits
    Trouble paying attention
    Memory loss
    Lowered judgment
    Trouble planning
    Other symptoms
    Anxiety
    Depression
    Suicidal thinking and behavior
    Movement abnormalities or catatonia
    Social difficulties
    Educational difficulties
    Work difficulties

    Your symptoms will depend on the type of schizophrenia you have: paranoid, disorganized, catatonic, residual, or undifferentiated. Paranoid schizophrenia is dominated by delusions and hallucinations, but exhibits few negative symptoms and little cognitive impairment. Disorganized schizophrenia is dominated by extremely disorganized thinking, speech, and behavior. Catatonic schizophrenia is very rare, and is characterized by episodes of prolonged speechlessness and lack of movement.

    Residual schizophrenia is characterized by negative symptoms in the absence of positive symptoms.

    Undifferentiated schizophrenia occurs when none of the above categories apply. Undifferentiated schizophrenia is the most common subtype, followed by the paranoid subtype.

    Having a family history of schizophrenia is a risk factor for developing the disease Table 02. Family studies show that there is a genetic component to schizophrenia. You have a greater chance of developing schizophrenia if a first-degree relative such as a parent or sibling also has the disease.

    Table 2.  Percent Risk of Developing Schizophrenia

    Family member(s) with schizophrenia Percent chance child will develop schizophrenia
    Both parents 46%
    Sibling and one parent 17%
    One parent 13%
    One sibling 10%
    Identical twin 50%
    Fraternal twin 20%

    Some inconclusive studies have revealed that children who exhibit certain behaviors are more likely to develop schizophrenia as adults. According to these studies, children with delayed motor milestones, neurological deficits, lower IQ, attention, and related cognitive difficulties, and impaired social and scholastic achievement have been found more likely to develop adult schizophrenia than children without these traits.

    Your doctor will diagnose schizophrenia primarily based on your symptoms. In general, your symptoms must cause significant social and occupational dysfunction, and last for at least six months before your doctor can diagnose schizophrenia. This six-month period must include at least one month where characteristic symptoms were present for a significant portion of time.

    Your doctor must rule out other medical conditions before diagnosing schizophrenia. A complete medical history and physical examination are necessary to determine whether your psychosis is due to schizophrenia, or to another medical condition. There are several psychiatric disorders that can have symptoms similar to those of schizophrenia. They include:

    • Schizophreniform disorder. This disorder has the same symptoms of schizophrenia, but lasts less than six months. This diagnosis may be made early in the course of the illness, and be changed to schizophrenia if symptoms persist for more than six months.
    • Schizoaffective disorder. This disorder is very much like schizophrenia, but disturbances in mood, either manic or depressive, are a prominent and persistent part of the overall illness.
    • Brief psychotic disorder. The symptoms for this disorder last for at least one day, but no longer than one month, and are often attributable to overwhelming stress.
    • Delusional disorder. In this disorder, delusions that ordinary events have special significance are present for at least one month in the absence of other symptoms of schizophrenia.
    • Drug-induced psychosis. Certain chemical substances such as amphetamines, cocaine, ecstasy, and phencyclidine can induce psychosis. Prescription medication such as certain antibiotics, cardiovascular drugs, and anticholinergics can also induce psychosis.

    Your doctor may order lab tests to rule out medical conditions that may be causing your symptoms. Although there are no laboratory tests specific for schizophrenia, your doctor may run lab tests to exclude other possible causes for your symptoms. Some such tests include syphilis screening, thyroid-function studies, liver function tests, and a toxicology screen.

  • Prevention and Screening

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