The term schizophrenia refers to a class of disorders marked by disturbances of perceptual symptoms (hallucinations - perception of things in the absence of any physical presence), cognitive symptoms (delusions - false beliefs), and emotional symptoms - such as flat effect (a blunting of emotions) or inappropriate effect - and even motor behavior. These symptoms are sometimes characterized as being either negative or positive. Negative symptoms include deficits in behavior, such as affective flattening, language deficits, apathy, and avoidance of social activity. Positive symptoms include delusions, hallucinations, and bizarre behavior.
To be diagnosed as schizophrenic, an individual must show (1) impairment in areas such as work, social relations, and self-care; (2) at least two of the cognitive, affective, or motor characteristics; and (3) persistence of these symptoms for at least 6 months.
The prognosis for schizophrenia is not particularly encouraging. Schizophrenia typically involves a series of acute episodes with intermittent periods of remission. In many cases, the victim's ability to function during the periods of remission declines with each successive acute episode. The consensus is that once people have a full-fledged episode of schizophrenia, they are rarely completely rid of the disorder. In other words, the disease process appears to be chronic. Despite disagreement about this prognosis, many psychologists believe that, in most cases, a number of the symptoms can be treated through psychotherapy and drugs.
Schizophrenia affects 1% to 2% of the population. The disorder tends to run in families. A review of several studies on the genetic transmission of schizophrenia found that a relative of a schizophrenic is 10 times more likely than a nonrelative to develop this disorder. Families seem to inherit a predisposition to schizophrenia. For example, among schizophrenics the prevalence of rates of schizophrenia are 44% for identical twins, 7% for siblings, 9% for children, and 3% for grandchildren.
Schizophrenia is generally diagnosed in early adulthood, usually before age 45. Schizophrenia also has been found to vary with socioeconomic status (SES). In particular, members of the lowest SES group are roughly eight times more likely to suffer from schizophrenia than are members of the middle and upper SES groups.
DSM-IV recognizes five main types of schizophrenia: disorganized schizophrenia, catatonic schizophrenia, paranoid schizophrenia, undifferentiated schizophrenia, and residual schizophrenia.
Why is there such a pronounced difference among the SES groups? According to the social-drift hypothesis, those who suffer from schizophrenia tend to drift downward in SES. Their inability to hold a job, earn a living, to relate to other people, and to function effectively leads them to successively lower SES levels until they bottom out. Evidence shows that schizophrenics are much more likely than others to drift downward in SES.
An alternate explaination is that the social and economic conditions a person faces in the lowest SES groups are so stressful that they tend to precipitate schizophrenia, at least more so than is the case for conditions in higher SES groups. According to the diathesis-stress theory, people with a genetic susceptibility to schizophrenia are more likely to display it when they are subjected to life stresses. Data suggests that members of groups experiencing discrimination and the stress that results from it are more prone to schizophrenia, regardless of social class. Still another explaination is that people with higher SES may be able to hide their symptoms better or they may have more help from others in hiding their symptoms. Also, if psychiatrically asessed, it appears that the lower SES individual is more likely to be diagnosed as schizophrenic, even if the symptoms are the same as those of someone with higher SES.
The many explainations of schizophrenia are not necessarily mutually exclusive. They may simply apply to different kinds or levels of severity of schizophrenia. None of these theories seem to account for all aspects of each of the schizophrenic disorders.
The psychodynamic paradigm has offered some explanations for schizophrenia that currently do not receive much support. The classical Freudian explanation of schizophrenia is in terms of primary narcissism - that is, the schizophrenic returns to the very early stages of psychological development. This phase occurs early during the oral stage, before the ego has differentiated itself from the id. In this phase, reality resting suffers because the ego is undifferentiated; schizophrenics are securely wrapped up in themselves but out of touch with the world. However, even Freud felt that his theory did not have an adequate explaination or means of treating schizophrenia.
A prominent learning-based theory is known as labeling theor, which holds that once people are labeled as schizophrenics, they are more likely to exhibit symptoms of schizophrenia, in part because they come to feel rewarded for acting this way, or others are rewarded for labeling them this way. For one thing, persons who have been labeled schizophrenics may then feel free (or even expected) to engage in antisocial behavior that would be prohibited in so-called normal people. Also, once they begin acting abnormally, more of their actions are are likely to be interpreted as being abnormal. For example, it was observed that the behavior of patients in psychiatric wards is likely to be viewed as abnormal, even if the patients are normal, mentally healthy individuals. According to this theory, someone who begins to act strangely and is later labeled a schizophrenic is susceptible to actually becoming schizophrenic merely because of the labeling process. Thus, the very fact of the label may create a self-fulfilling prophecy.
However, the preponderance of evidence does not favor labeling theory. If labeling theory were correct, one might expect, say, that in other cultures, schizophrenic behavior would be viewed as quite normal. But in both the Eskimo and Yoruba cultures, for example, the behavior labeled in our society as schizophrenic is also viewed as "crazy." Thus, there is at least some overlap in what is seen as nonadaptive across societies. For the most part, it would be hard to argue that the labels are extremely arbitrary.
Essentially, cognitive explanations of schizophrenia suggest that people who are schizophrenic have sensory experiences that differ from those of normal individuals. From this perspective, many of the symptoms of schizophrenia could be constructed as attempts by people suffering from these symptoms to explain their sensory experiences to others. Unlike the other explanations of schizophrenia we have considered, cognitive explanations interpret the bizzare sensory experiences of schizophrenics as being genuine sensory experiences and as causing the disorder. According to this view, breakdowns in communication with schizophrenics often result from their attempt to explain what is happening to them. People with schizophrenia are viewed as being particularly susceptible to stimulus overload, which leads them to function in a maladaptive manner. It may be that schizophrenics lack a kind of filtering mechanism that allows most people to screen out irrelevant stimuli.
Humanistic psychologists usually deal with disorders that are less seriously disruptive than is schizophrenia. However, several humanistic psychologists have taken quite unorthodox views. One argued that mental illness is simply a myth - that schizophrenia and other so-called mental illnesses are merely alternative ways of experiencing the world. In a related vein, a therapist suggested that schizophrenia is not an illness but merely a label that society applies to behavior it finds problematic. According to him, people become schizophrenic when they live in situations that are simply not livable. No matter what they do, nothing seems to work, and they feel symbolically in a position of checkmate. Today, these theories are given little credence.
Biological explanations of schizophrenia emphasize neurochemical imbalances. Some of the most promising explanations of schizophrenia today are biological. One such view holds that schizophrenia results from an excess of the neurotransmitter dopamine, although the evidence is mixed. Another biological explanation suggests structural abnormalities in the brain as the cause. Some evidence indicates that schizophrenics have enlarged ventricles in the brain. These ventricles - the canals through which cerebrospinal fluid (SCF) flows - generally appear enlarged when the surrounding tissue has atrophied, and additional evidence documents atrophy in portions of the brains of schizophrenics. Another intriguing finding is that in a card-sorting task, schizophrenics show less actuation of the prefrontal region of the brain than do nonschizophrenics. The prefrontal cortex is generally smaller as well as showing less activation in people with schizophrenia than in those without this disorder.
One possible biological explanation of schizophrenia, or at least certain variants of it, is that it is primarily caused by a virus contraced by the mother during the prenatal period (and usually the second trimester, when the brain is developing most rapidly). Such an explanation might account for why mothers exposed to the influenza virus during the second trimester of pregnancy have a somewhat greater tendency to have children who later develop schizophrenia. At the present time, though, the virus explanation must be viewed as still being rather speculative. A second and even more speculative viral explanation is that it is itself caused by a slow-acting virus.
Nonpsychologists confuse schizophrenia with what is popularly called "multiple personality disorder." This disorder, formally known as dissociative identity disorder, is included in another section.