Abstract
Schizophrenia is the most common and important type of a primary psychotic disorder (i.e., not caused by drugs or a medical condition), representing more than half of all patients with a psychotic disorder. In this chapter, we will follow the DSM-V framework and review schizophrenia and related disorders as schizophrenia spectrum disorders (i.e., schizoaffective disorder, delusional disorder, schizophreniform disorder, brief psychotic disorder, and shared psychotic disorder). Schizotypal personality disorder, which is closely related (and often considered a schizophrenia spectrum disorder), is discussed elsewhere in this book.
Introduction
Schizophrenia is the most common and important type of a primary psychotic disorder (i.e., not caused by drugs or a medical condition), representing more than half of all patients with a psychotic disorder. In this chapter, we will follow the DSM-5 framework and review schizophrenia and related disorders as schizophrenia spectrum disorders (i.e., schizoaffective disorder, delusional disorder, schizophreniform disorder, brief psychotic disorder). Schizotypal personality disorder, which is closely related (and often considered a schizophrenia spectrum disorder), is discussed elsewhere in this book.
Classification
All schizophrenia spectrum disorders are diagnoses of exclusion – that is, the physician needs to obtain a clinical history and carry out the mental status and physical examination in order to rule out other (secondary) causes of psychotic symptoms to make the diagnosis of a primary psychiatric condition as the cause for the psychosis. A distinction between the various psychotic disorders themselves is made based on presenting symptom patterns and illness course.
Schizophrenia
Schizophrenia is one of the most devastating psychiatric disorders and most important public health problems in the world. It strikes just as individuals are preparing to enter adulthood and often follows a relapsing-remitting lifelong pattern. It affects not only the patients but also their families and friends.
The term “schizophrenia” is derived from the Greek “schizo” (split, fragmented) and “phrenia” (mind) to describe the disjointed experience of people with the disorder (e.g., contradictory thought content and affect). This term was not meant to convey the idea of split or multiple personality, as many assume. Although the term “schizophrenia” is relatively new, schizophrenia-like psychosis has been recognized since at least the second millennium BC. In 1893, Emil Kraepelin coined the term “dementia praecox” for this condition, which was renamed “schizophrenia” by Eugen Bleuler in 1911.
In DSM-5, schizophrenia is defined by a group of characteristic symptoms, such as delusions, hallucinations, negative symptoms; deterioration in social, occupational, or interpersonal relationships; and continuous signs of the disturbance for at least six months (Table 5.1). The tenth edition of the International Classifications of Disease (ICD-10) system, which is used in many countries, is broadly comparable to the DSM classification, although it differs in some details. For example, schizophrenia can already be diagnosed after thirty days of typical symptoms, and no deterioration in function is required.
Schizoaffective Disorder
Schizoaffective disorder is characterized by a combination of symptoms found in patients with schizophrenia and in patients with mood disorders. In order to consider schizoaffective disorder, hallucinations or delusions must be present for two weeks or more in the absence of prominent mood symptoms, but mood symptoms must be present for a majority of the total duration of illness. The correct application of the criteria for schizoaffective disorder requires knowledge about the longitudinal illness course and cannot be made based on a cross-sectional symptom review alone. DSM-5 diagnostic criteria for schizoaffective disorder are presented in Table 5.2.
Table 5.2 Diagnostic criteria for schizoaffective disorder (DSM-5)
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Schizoaffective disorder shares many features with schizophrenia. The key distinction is the prominent role played by mood episodes (depression and mania) in this condition. Note that patients with schizophrenia often experience mood symptoms as well. But the diagnosis is not converted to schizoaffective disorder unless mood symptoms are prominent and present for a majority of the total duration of illness. Symptoms usually begin in early adulthood. The lifetime prevalence of the disorder is somewhat less than 1 percent (i.e., comparable to that of schizophrenia). Therefore, this is a common clinical problem for clinicians treating psychotic disorders. It may occur more often in women. The most important psychiatric differential diagnosis for schizoaffective disorder consists of schizophrenia and psychotic mood disorders such as bipolar disorder. However, psychotic disorders induced by medical illness (e.g., HIV, neurosyphilis, epilepsy) or drugs (amphetamine) can mimic the course and symptom psychiatric symptom mixture seen in schizoaffective disorder. As a group, patients with schizoaffective disorder have a more favorable prognosis than those with schizophrenia, and a worse prognosis than those with psychotic mood disorders. The mainstay of treatment are antipsychotic medications, just as in schizophrenia, but in this case, antipsychotics may need to be combined with a mood stabilizer, or an antidepressant, or both.
Delusional Disorder
Delusional disorder is a psychotic disorder in which patients experience persistent delusions as the main psychiatric symptom (i.e., there are no accompanying prominent hallucinations or a formal thought disorder or negative symptoms). The delusions are typically not bizarre (clearly implausible such as violating laws of physics), but the distinction between bizarre and non-bizarre can be difficult to draw in specific cases. Delusions need to last for at least one month for this disorder to be considered.
Delusional disorder is not common, and when it does occur, individuals come to treatment infrequently because functioning is preserved in all areas other than the delusional beliefs. It affects more women than men. Some studies suggest that men are more likely to develop paranoid delusions while women are more likely to develop erotomanic ones. Associated factors include being married, being employed, recent immigration, and low socioeconomic status. This disorder has its onset much more commonly in the middle decades of life, unlike other psychotic disorders, which have typical ages at onset of eighteen through twenty-five.
Differential diagnosis includes other causes of psychosis such as drug-induced conditions, dementia, and other psychiatric disorders. In delusional disorder, mood symptoms tend to be brief or absent; delusions are almost always non-bizarre and hallucinations are minimal or absent. Antipsychotic medication may be useful, particularly for accompanying anxiety and agitation if not for dissolving the core delusional belief.
Schizophreniform Disorder
In schizophreniform disorder, typical schizophrenia symptoms are present for a significant portion of the time within a one-month period, but signs of disruption are not present for the full six months required for the diagnosis of schizophrenia. In this condition, full criteria for schizophrenia would have been met with the exception of the six-month overall duration. As a corollary, most individuals who receive this diagnosis are simply in the early stages of schizophrenia and the diagnosis will convert to schizophrenia (or schizoaffective disorder) once the duration criterion has been met.
Brief Psychotic Disorder
In this condition, patients have psychotic symptoms that generally last at least a day, but not more than a month, and there is an eventual return to full baseline functioning. Signs and symptoms are similar to those seen in schizophrenia, and other etiologies have been ruled out as causing the symptoms. In the DSM-5, three specifiers for brief psychotic disorder can be assigned: with marked stressor(s) (i.e., brief reactive psychosis); without marked stressor(s); and with postpartum onset (during pregnancy or within four weeks postpartum). In other nomenclatures, this condition is accordingly referred to as brief reactive psychosis or acute and transient psychotic disorder (ATPD).
Since brief psychotic disorder is by definition associated with a full return to premorbid level of functioning, it is a condition with a good prognosis. As such, it appears to represent a different kind of psychotic disorder than the other schizophrenia spectrum disorders. Its prevalence is unknown. It occurs at least twice as often in women than in men. Hospitalization may be necessary for acute stabilization as well as for the protection of the individual and others. During the symptomatic phase, antipsychotic medications are uniformly used but long-term pharmacotherapy is not indicated if the diagnosis is well-established. However, the relapse risk can be high, and patients might opt for maintenance treatment (antipsychotic or lithium) to prevent another episode once it has become clear that a patient has a remitting-relapsing form of the illness.
Shared Psychotic Disorder
Shared psychotic disorder (folie à deux), is a rare and peculiar form of psychosis that is not listed in the DSM-5. Since its recognition can lead to effective treatment, we discuss it here. This is a delusional disorder in which an otherwise healthy person shares the delusional beliefs of a person with a psychotic disorder. This disorder usually occurs in long-term relationships in which one person is dominant and the other is submissive. Most cases involve two members of the same family, most commonly siblings or a parent and child. The treatment is to separate the two individuals, as this results in rapid improvement of the person who does not have a chronic psychotic illness.
Attenuated Psychosis Syndrome
DSM-5 includes the attenuated psychosis syndrome as a “condition for further study” – that is, a condition where further research is encouraged with consideration of placement in the official diagnostic system in future editions. This syndrome requires the presence of attenuated psychotic symptoms sufficient to warrant clinical attention but criteria for any psychotic disorder have never been met. Attenuated psychotic are, as the name implies, milder forms of psychotic symptoms. Typically and in contradistinction to severe psychosis, patients retain insight into the abnormal nature of their experiences. Some individuals who meet criteria for this syndrome progress to be diagnosed with psychotic disorders in the future; therefore the concept is related (but not identical) to the prodrome described under the “Clinical Course” later in this chapter.
Epidemiology and Burden of Illness
Schizophrenia is among the more common disorders in medicine and is the most common psychotic condition. In population-based studies, the prevalence of schizophrenia worldwide is typically found to be in the range of 0.5–1.5 percent of the general population. According to the National Institute of Mental Health (NIMH), about 1.1 percent of the population over the age of 18 in the United States has schizophrenia, which amounts to about 2.5 million people. The World Health Organization (WHO) estimates that schizophrenia affects about 24 million people across the world.
In addition to being common, schizophrenia is also costly to both the afflicted individual and to the society. According to the Global Burden of Disease study of the cost of illness worldwide, schizophrenia is among the ten leading causes of disability among people in the fifteen to forty-four age range. The financial cost of schizophrenia in the United States is estimated to be $130 billion annually, including direct health care costs but also disability income and community services. Nationwide in the United States, individuals with schizophrenia account for approximately 20 percent of all social security disability days, and 25 percent of psychiatric hospital bed days are devoted to individuals with schizophrenia. In terms of the average cost per patient, schizophrenia is the second most costly disease, at more than $16,000 patient/year (Figure 5.1). This makes the average cost per patient greater than that for cancer, stroke, and diabetes mellitus (DM) because the condition is chronic and relapsing-remitting.
Figure 5.1 Yearly cost per patient of selected medical conditions: United States US$/patient/year
Suicide, Violence, and Mortality
The World Health Organization calculates the lifetime global risk of suicide globally for people with schizophrenia as 10–13 percent, twelve times the general population risk. However, recent studies indicate that this figure represents risk in early stages of illness because the highest risk of suicide is usually within a year or two of symptom onset. Total lifetime risk of suicide is probably closer to 5 percent in schizophrenia. More than 40 percent of people with schizophrenia will attempt suicide at least once (60 percent of males and 20 percent of females), and twice that rate will develop suicidal ideation. Completed suicide is more common in males.
Although many in society believe that people with schizophrenia are likely to be violent, violence is not a core and characteristic symptom of schizophrenia, although some acutely psychotic patients can be violent, with drug use and antisocial personality traits being risk factors. Individuals with schizophrenia are in fact at higher risk of being victims of violence than perpetrating it. In addition, people with schizophrenia are far more likely to harm themselves than harm anyone else. Mortality rates are eight times higher in this condition than in the general population, due to suicide, accidents, and violence, as well as medical causes. As a result, patients with schizophrenia have on average a reduced life-expectancy that is a decade and a half shorter than their peers without schizophrenia. Cardiovascular and cerebrovascular diseases and cancer are the main medical causes of death in these patients. Contributing factors include fragmentation of care, smoking, and iatrogenic morbidity. While mortality rates are falling in the general population, they are still rising among people with schizophrenia. Advances in modern medicine generally and improved treatments for the condition itself have not made the desired impact for this patient population of patients with serious mental illness.
Risk Factors
Risk factors for schizophrenia have been the subject of much debate. The most widely accepted risk factors include the following.
Family History
Twin, adoption, and family studies show that schizophrenia has a strong genetic component. Family history of schizophrenia is the best-established risk factor for the disorder. A child whose parent has schizophrenia has about a 10 percent chance of developing schizophrenia. The risk is even higher, as high as 50 percent, among monozygotic twins who share their entire DNA.
Insults to Early Brain Development
People who are born during times of famine are more than twice as likely to develop schizophrenia as those born in previous or subsequent years in the same part of the world. This relationship has been demonstrated in Holland during the famine of 1944 and in parts of China during the Cultural Revolution. Likewise, people who were exposed in utero during a particularly severe flu epidemic in Helsinki, Finland, had a threefold higher risk of schizophrenia as adults than the general population. Finally, people with schizophrenia are more likely to have had difficult births, particularly perinatal hypoxia. Perhaps related to this literature on early brain development are the studies suggesting that individuals who experience abuse in early childhood are at higher risk of being diagnosed with schizophrenia in the future.
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