About half of those diagnosed with schizophrenia will have a significant improvement over the long term with no further relapses, and a small proportion of these will recover completely. The other half will have a lifelong impairment. In severe cases, people may be admitted to hospitals. Social problems such as long-term unemployment, poverty, homelessness, exploitation, and victimization are commonly correlated with schizophrenia. Compared to the general population, people with schizophrenia have a higher suicide rate (about 5% overall) and more physical health problems, leading to an average decrease in life expectancy by 20 to 28 years. In 2015, an estimated 17,000 deaths were linked to schizophrenia.
The mainstay of treatment is antipsychotic medication, along with counseling, job training, and social rehabilitation. Up to a third of people do not respond to initial antipsychotics, in which case clozapine may be used. In a network comparative meta-analysis of 15 antipsychotic drugs, clozapine was significantly more effective than all other drugs, although clozapine's heavily multimodal action may cause more side effects. In situations where doctors judge that there is a risk of harm to self or others, they may impose short involuntary hospitalization. Long-term hospitalization is used on a small number of people with severe schizophrenia. In some countries where supportive services are limited or unavailable, long-term hospital stays are more common.
Signs and symptoms
Schizophrenia is a mental disorder characterized by significant alterations in perception, thoughts, mood, and behavior. Symptoms are described in terms of positive, negative, and cognitive symptoms. The positive symptoms of schizophrenia are the same for any psychosis and are sometimes referred to as psychotic symptoms. These may be present in any of the different psychoses, and are often transient making early diagnosis of schizophrenia problematic. Psychosis noted for the first time in a person who is later diagnosed with schizophrenia is referred to as a first-episode psychosis (FEP).
Negative symptoms are deficits of normal emotional responses, or of other thought processes. The five recognized domains of negative symptoms are: blunted affect – showing flat expressions or little emotion; alogia – a poverty of speech; anhedonia – an inability to feel pleasure; asociality – the lack of desire to form relationships, and avolition – a lack of motivation and apathy. Avolition and anhedonia are seen as motivational deficits resulting from impaired reward processing. Reward is the main driver of motivation and this is mostly mediated by dopamine. It has been suggested that negative symptoms are multidimensional and they have been categorised into two subdomains of apathy or lack of motivation, and diminished expression. Apathy includes avolition, anhedonia, and social withdrawal; diminished expression includes blunt affect and alogia. Sometimes diminished expression is treated as both verbal and non-verbal.
Apathy accounts for around 50 percent of the most often found negative symptoms and affects functional outcome and subsequent quality of life. Apathy is related to disrupted cognitive processing affecting memory and planning including goal-directed behaviour. The two subdomains have suggested a need for separate treatment approaches. A lack of distress – relating to a reduced experience of depression and anxiety is another noted negative symptom. A distinction is often made between those negative symptoms that are inherent to schizophrenia, termed primary; and those that result from positive symptoms, from the side effects of antipsychotics, substance use disorder, and social deprivation – termed secondary negative symptoms. Negative symptoms are less responsive to medication and the most difficult to treat. However, if properly assessed, secondary negative symptoms are amenable to treatment.
Scales for specifically assessing the presence of negative symptoms, and for measuring their severity, and their changes have been introduced since the earlier scales such as the PANNS that deals with all types of symptoms. These scales are the Clinical Assessment Interview for Negative Symptoms (CAINS), and the Brief Negative Symptom Scale (BNSS) also known as second-generation scales. In 2020, ten years after its introduction, a cross-cultural study of the use of BNSS found valid and reliable psychometric evidence for its five-domain structure cross-culturally. The BNSS can assess both the presence and severity of negative symptoms of the five recognized domains and an additional item of reduced normal distress. It has been used to measure changes in negative symptoms in trials of psychosocial and pharmacological interventions.
An estimated 70% of those with schizophrenia have cognitive deficits, and these are most pronounced in early onset and late-onset illness. These are often evident long before the onset of illness in the prodromal stage, and may be present in early adolescence, or childhood. They are a core feature but not considered to be core symptoms, as are positive and negative symptoms. However, their presence and degree of dysfunction is taken as a better indicator of functionality than the presentation of core symptoms. Cognitive deficits become worse at first episode psychosis but then return to baseline, and remain fairly stable over the course of the illness.
Onset typically occurs between the late teens and early 30s, with the peak incidence occurring in males in the early to mid-twenties, and in females in the late twenties. Onset before the age of 17 is known as early-onset, and before the age of 13, as can sometimes occur, is known as childhood schizophrenia or very early-onset. Onset can occur between the ages of 40 and 60, known as late-onset schizophrenia. Onset over the age of 60, which may be difficult to differentiate as schizophrenia, is known as very-late-onset schizophrenia-like psychosis. Late onset has shown that a higher rate of females are affected; they have less severe symptoms and need lower doses of antipsychotics. The tendency for earlier onset in males is later seen to be balanced by a post-menopausal increase in the development in females. Estrogen produced pre-menopause has a dampening effect on dopamine receptors but its protection can be overridden by a genetic overload. There has been a dramatic increase in the numbers of older adults with schizophrenia.
Onset may happen suddenly or may occur after the slow and gradual development of a number of signs and symptoms, a period known as the prodromal stage. Up to 75% of those with schizophrenia go through a prodromal stage. The negative and cognitive symptoms in the prodrome stage can precede FEP (first episode psychosis) by many months and up to five years. The period from FEP and treatment is known as the duration of untreated psychosis (DUP) which is seen to be a factor in functional outcome. The prodromal stage is the high-risk stage for the development of psychosis. Since the progression to first episode psychosis is not inevitable, an alternative term is often preferred of at risk mental state. Cognitive dysfunction at an early age impacts a young person's usual cognitive development. Recognition and early intervention at the prodromal stage would minimize the associated disruption to educational and social development and has been the focus of many studies.
Schizophrenia is described as a neurodevelopmental disorder with no precise boundary, or single cause, and is thought to develop from gene–environment interactions with involved vulnerability factors. The interactions of these risk factors are complex, as numerous and diverse insults from conception to adulthood can be involved. A genetic predisposition on its own, without interacting environmental factors, will not give rise to the development of schizophrenia. The genetic component means that prenatal brain development is disturbed, and environmental influence affects the postnatal development of the brain. Evidence suggests that genetically susceptible children are more likely to be vulnerable to the effects of environmental risk factors.
Estimates of the heritability of schizophrenia are between 70% and 80%, which implies that 70% to 80% of the individual differences in risk of schizophrenia are associated with genetics. These estimates vary because of the difficulty in separating genetic and environmental influences, and their accuracy has been queried. The greatest risk factor for developing schizophrenia is having a first-degree relative with the disease (risk is 6.5%); more than 40% of identical twins of those with schizophrenia are also affected. If one parent is affected the risk is about 13% and if both are affected the risk is nearly 50%. However, the DSM-5 indicates that most people with schizophrenia have no family history of psychosis. Results of candidate gene studies of schizophrenia have generally failed to find consistent associations, and the genetic loci identified by genome-wide association studies explain only a small fraction of the variation in the disease.
The genes CRHR1 and CRHBP are associated with the severity of suicidal behavior. These genes code for stress response proteins needed in the control of the HPA axis, and their interaction can affect this axis. Response to stress can cause lasting changes in the function of the HPA axis possibly disrupting the negative feedback mechanism, homeostasis, and the regulation of emotion leading to altered behaviors.
The question of how schizophrenia could be primarily genetically influenced, given that people with schizophrenia have lower fertility rates, is a paradox. It is expected that genetic variants that increase the risk of schizophrenia would be selected against, due to their negative effects on reproductive fitness. A number of potential explanations have been proposed, including that alleles associated with schizophrenia risk confers a fitness advantage in unaffected individuals. While some evidence has not supported this idea, others propose that a large number of alleles each contributing a small amount can persist.
A meta-analysis found that oxidative DNA damage was significantly increased in schizophrenia.
Environmental factors, each associated with a slight risk of developing schizophrenia in later life include oxygen deprivation, infection, prenatal maternal stress, and malnutrition in the mother during prenatal development. A risk is associated with maternal obesity, in increasing oxidative stress, and dysregulating the dopamine and serotonin pathways. Both maternal stress and infection have been demonstrated to alter fetal neurodevelopment through an increase of pro-inflammatory cytokines. There is a slighter risk associated with being born in the winter or spring possibly due to vitamin D deficiency or a prenatal viral infection. Other infections during pregnancy or around the time of birth that have been linked to an increased risk include infections by Toxoplasma gondii and Chlamydia. The increased risk is about five to eight percent. Viral infections of the brain during childhood are also linked to a risk of schizophrenia during adulthood.
Adverse childhood experiences (ACEs), severe forms of which are classed as childhood trauma, range from being bullied or abused, to the death of a parent. Many adverse childhood experiences can cause toxic stress and increase the risk of psychosis. Chronic trauma, including ACEs, can promote lasting inflammatory dysregulation throughout the nervous system. It is suggested that early stress may contribute to the development of schizophrenia through these alterations in the immune system. Schizophrenia was the last diagnosis to benefit from the link made between ACEs and adult mental health outcomes.
Cannabis use may be a contributory factor in the development of schizophrenia, potentially increasing the risk of the disease in those who are already at risk. The increased risk may require the presence of certain genes within an individual. Its use is associated with doubling the rate.
The causes of schizophrenia are unknown, and a number of models have been put forward to explain the link between altered brain function and schizophrenia. The prevailing model of schizophrenia is that of a neurodevelopmental disorder, and the underlying changes that occur before symptoms become evident are seen as arising from the interaction between genes and the environment. Extensive studies support this model. Maternal infections, malnutrition and complications during pregnancy and childbirth are known risk factors for the development of schizophrenia, which usually emerges between the ages of 18 and 25, a period that overlaps with certain stages of neurodevelopment. Gene-environment interactions lead to deficits in the neural circuitry that affect sensory and cognitive functions.
The common dopamine and glutamate models proposed are not mutually exclusive; each is seen to have a role in the neurobiology of schizophrenia. The most common model put forward was the dopamine hypothesis of schizophrenia, which attributes psychosis to the mind's faulty interpretation of the misfiring of dopaminergic neurons. This has been directly related to the symptoms of delusions and hallucinations. Abnormal dopamine signaling has been implicated in schizophrenia based on the usefulness of medications that affect the dopamine receptor and the observation that dopamine levels are increased during acute psychosis. A decrease in D1 receptors in the dorsolateral prefrontal cortex may also be responsible for deficits in working memory.
Deficits in executive functions, such as planning, inhibition, and working memory, are pervasive in schizophrenia. Although these functions are separable, their dysfunction in schizophrenia may reflect an underlying deficit in the ability to represent goal related information in working memory, and to use this to direct cognition and behavior. These impairments have been linked to a number of neuroimaging and neuropathological abnormalities. For example, functional neuroimaging studies report evidence of reduced neural processing efficiency, whereby the dorsolateral prefrontal cortex is activated to a greater degree to achieve a certain level of performance relative to controls on working memory tasks. These abnormalities may be linked to the consistent post-mortem finding of reduced neuropil, evidenced by increased pyramidal cell density and reduced dendritic spine density. These cellular and functional abnormalities may also be reflected in structural neuroimaging studies that find reduced grey matter volume in association with deficits in working memory tasks.
Positive symptoms have been linked to cortical thinning in the superior temporal gyrus. The severity of negative symptoms has been linked to reduced thickness in the left medial orbitofrontal cortex. Anhedonia, traditionally defined as a reduced capacity to experience pleasure, is frequently reported in schizophrenia. However, a large body of evidence suggests that hedonic responses are intact in schizophrenia, and that what is reported to be anhedonia is a reflection of dysfunction in other processes related to reward. Overall, a failure of reward prediction is thought to lead to impairment in the generation of cognition and behavior required to obtain rewards, despite normal hedonic responses.
Another theory links abnormal brain lateralization to the development of being left-handed which is significantly more common in those with schizophrenia. This abnormal development of hemispheric asymmetry is noted in schizophrenia. Studies have concluded that the link is a true and verifiable effect that may reflect a genetic link between lateralization and schizophrenia.
Bayesian models of brain functioning have been used to link abnormalities in cellular functioning to symptoms. Both hallucinations and delusions have been suggested to reflect improper encoding of prior expectations, thereby causing expectation to excessively influence sensory perception and the formation of beliefs. In approved models of circuits that mediate predictive coding, reduced NMDA receptor activation, could in theory result in the positive symptoms of delusions and hallucinations.
DSM-5 states that to be diagnosed with schizophrenia, two diagnostic criteria have to be met over the period of one month, with a significant impact on social or occupational functioning for at least six months. One of the symptoms needs to be either delusions, hallucinations, or disorganized speech. A second symptom could be one of the negative symptoms, or severely disorganized or catatonic behaviour. A different diagnosis of schizophreniform disorder can be made before the six months needed for the diagnosis of schizophrenia.
In Australia, the guideline for diagnosis is for six months or more with symptoms severe enough to affect ordinary functioning. In the UK diagnosis is based on having the symptoms for most of the time for one month, with symptoms that significantly affect the ability to work, study, or carry on ordinary daily living, and with other similar conditions ruled out.
The ICD criteria are typically used in European countries; the DSM criteria are used predominantly in the United States and Canada, and are prevailing in research studies. In practice, agreement between the two systems is high. The current proposal for the ICD-11 criteria for schizophrenia recommends adding self-disorder as a symptom.
A major unresolved difference between the two diagnostic systems is that of the requirement in DSM of an impaired functional outcome. WHO for ICD argues that not all people with schizophrenia have functional deficits and so these are not specific for the diagnosis.
Sleep disorders often co-occur with schizophrenia, and may be an early sign of relapse. Sleep disorders are linked with positive symptoms such as disorganized thinking and can adversely affect cortical plasticity and cognition. The consolidation of memories is disrupted in sleep disorders. They are associated with severity of illness, a poor prognosis, and poor quality of life. Sleep onset and maintenance insomnia is a common symptom, regardless of whether treatment has been received or not. Genetic variations have been found associated with these conditions involving the circadian rhythm, dopamine and histamine metabolism, and signal transduction.
Schizophrenia is also associated with a number of somatic comorbidities including diabetes mellitus type 2, autoimmune diseases, and cardiovascular diseases. The association of these with schizophrenia may be partially due to medications (e.g. dyslipidemia from antipsychotics), environmental factors (e.g. complications from an increased rate of cigarette smoking), or associated with the disorder itself (e.g. diabetes mellitus type 2 and some cardiovascular diseases are thought to be genetically linked). These somatic comorbidities contribute to reduced life expectancy among persons with the disorder.
Antipsychotics are prescribed following a first-episode psychosis, and following remission, a preventive maintenance use is continued to avoid relapse. However, it is recognized that some people do recover following a single episode and that long-term use of antipsychotics will not be needed but there is no way of identifying this group.
Voluntary or involuntary admission to hospital may be imposed by doctors and courts who deem a person to be having a severe episode. In the UK, large mental hospitals termed asylums began to be closed down in the 1950s with the advent of antipsychotics, and with an awareness of the negative impact of long-term hospital stays on recovery. This process was known as deinstitutionalization, and community and supportive services were developed to support this change. Many other countries followed suit with the US starting in the 60s. There still remain a smaller group of people who do not improve enough to be discharged. In some countries that lack the necessary supportive and social services, long-term hospital stays are more usual.
The first-line treatment for schizophrenia is an antipsychotic. The first-generation antipsychotics, now called typical antipsychotics, are dopamine antagonists that block D2 receptors, and affect the neurotransmission of dopamine. Those brought out later, the second-generation antipsychotics known as atypical antipsychotics, can also have an effect on another neurotransmitter, serotonin. Antipsychotics can reduce the symptoms of anxiety within hours of their use but for other symptoms they may take several days or weeks to reach their full effect. They have little effect on negative and cognitive symptoms, which may be helped by additional psychotherapies and medications. There is no single antipsychotic suitable for first-line treatment for everyone, as responses and tolerances vary between people. Stopping medication may be considered after a single psychotic episode where there has been a full recovery with no symptoms for twelve months. Repeated relapses worsen the long-term outlook and the risk of relapse following a second episode is high, and long-term treatment is usually recommended.
About half of those with schizophrenia will respond favourably to antipsychotics, and have a good return of functioning. However, positive symptoms persist in up to a third of people. Following two trials of different antipsychotics over six weeks, that also prove ineffective, they will be classed as having treatment resistant schizophrenia (TRS), and clozapine will be offered. Clozapine is of benefit to around half of this group although it has the potentially serious side effect of agranulocytosis (lowered white blood cell count) in less than 4% of people.
About 30 to 50 percent of people with schizophrenia do not accept that they have an illness or comply with their recommended treatment. For those who are unwilling or unable to take medication regularly, long-acting injections of antipsychotics may be used, which reduce the risk of relapse to a greater degree than oral medications. When used in combination with psychosocial interventions, they may improve long-term adherence to treatment.
A number of psychosocial interventions that include several types of psychotherapy may be useful in the treatment of schizophrenia such as: family therapy,group therapy, cognitive remediation therapy (CRT), cognitive behavioral therapy (CBT), and metacognitive training. Skills training, help with substance use, and weight management – often needed as a side effect of an antipsychotic – are also offered. In the US, interventions for first episode psychosis have been brought together in an overall approach known as coordinated speciality care (CSC) and also includes support for education. In the UK care across all phases is a similar approach that covers many of the treatment guidelines recommended. The aim is to reduce the number of relapses and stays in the hospital.
Other support services for education, employment, and housing are usually offered. For people with severe schizophrenia, who are discharged from a stay in the hospital, these services are often brought together in an integrated approach to offer support in the community away from the hospital setting. In addition to medicine management, housing, and finances, assistance is given for more routine matters such as help with shopping and using public transport. This approach is known as assertive community treatment (ACT) and has been shown to achieve positive results in symptoms, social functioning and quality of life. Another more intense approach is known as intensive care management (ICM). ICM is a stage further than ACT and emphasises support of high intensity in smaller caseloads, (less than twenty). This approach is to provide long-term care in the community. Studies show that ICM improves many of the relevant outcomes including social functioning.
Some studies have shown little evidence for the effectiveness of CBT in either reducing symptoms or preventing relapse. However, other studies have found that CBT does improve overall psychotic symptoms (when in use with medication) and it has been recommended in Canada, but has been seen to have no effect on social function, relapse, or quality of life. In the UK it is recommended as an add-on therapy in the treatment of schizophrenia.Arts therapies are seen to improve negative symptoms in some people, and are recommended by NICE in the UK. This approach is criticised as having not been well-researched, and arts therapies are not recommended in Australian guidelines for example.Peer support, in which people with personal experience of schizophrenia, provide help to each other, is of unclear benefit.
Exercise including aerobic exercise has been shown to improve positive and negative symptoms, cognition, working memory, and improve quality of life. Exercise has also been shown to increase the volume of the hippocampus in those with schizophrenia. A decrease in hippocampal volume is one of the factors linked to the development of the disease. However, there still remains the problem of increasing motivation for, and maintaining participation in physical activity. Supervised sessions are recommended. In the UK healthy eating advice is offered alongside exercise programs.
An inadequate diet is often found in schizophrenia, and associated vitamin deficiencies including those of folate, and vitamin D are linked to the risk factors for the development of schizophrenia and for early death including heart disease. Those with schizophrenia possibly have the worst diet of all the mental disorders. Lower levels of folate and vitamin D have been noted as significantly lower in first episode psychosis. The use of supplemental folate is recommended. A zinc deficiency has also been noted.Vitamin B12 is also often deficient and this is linked to worse symptoms. Supplementation with B vitamins has been shown to significantly improve symptoms, and to put in reverse some of the cognitive deficits. It is also suggested that the noted dysfunction in gut microbiota might benefit from the use of probiotics.
Schizophrenia has great human and economic costs. It decreases life expectancy by between 20 and 28 years. This is primarily because of its association with heart disease, diabetes,obesity, poor diet, a sedentary lifestyle, and smoking, with an increased rate of suicide playing a lesser role. Side effects of antipsychotics may also increase the risk.
Almost 40% of those with schizophrenia die from complications of cardiovascular disease which is seen to be increasingly associated. An underlying factor of sudden cardiac death may be Brugada syndrome (BrS) – BrS mutations that overlap with those linked with schizophrenia are the calcium channel mutations. BrS may also be drug-induced from certain antipsychotics and antidepressants.Primary polydipsia, or excessive fluid intake, is relatively common in people with chronic schizophrenia. This may lead to hyponatremia which can be life-threatening. Antipsychotics can lead to a dry mouth, but there are several other factors that may contribute to the disorder; it may reduce life expectancy by 13 percent. Barriers to improving the mortality rate in schizophrenia are poverty, overlooking the symptoms of other illnesses, stress, stigma, and medication side effects.
Schizophrenia is a major cause of disability. In 2016, it was classed as the 12th most disabling condition. Approximately 75% of people with schizophrenia have ongoing disability with relapses. Some people do recover completely and others function well in society. Most people with schizophrenia live independently with community support. About 85% are unemployed. In people with a first episode of psychosis in schizophrenia a good long-term outcome occurs in 31%, an intermediate outcome in 42% and a poor outcome in 31%. Males are affected more often than females, and have a worse outcome. Studies showing that outcomes for schizophrenia appear better in the developing than the developed world have been questioned. Social problems, such as long-term unemployment, poverty, homelessness, exploitation, stigmatization and victimization are common consequences, and lead to social exclusion.
There is a higher than average suicide rate associated with schizophrenia estimated at 5% to 6%, most often occurring in the period following onset or first hospital admission. Several times more (20 to 40%) attempt suicide at least once. There are a variety of risk factors, including male sex, depression, a high IQ, heavy smoking, and substance use. Repeated relapse is linked to an increased risk of suicidal behavior. The use of clozapine can reduce the risk of suicide, and of aggression.
A strong association between schizophrenia and tobacco smoking has been shown in worldwide studies.Smoking is especially high in those diagnosed with schizophrenia, with estimates ranging from 80 to 90% being regular smokers, as compared to 20% of the general population. Those who smoke tend to smoke heavily, and additionally smoke cigarettes with high nicotine content. Some propose that this is in an effort to improve symptoms. Among people with schizophrenia use of cannabis is also common.
Schizophrenia leads to an increased risk of dementia.
Most people with schizophrenia are not aggressive, and are more likely to be victims of violence rather than perpetrators. People with schizophrenia are commonly exploited and victimized by violent crime as part of a broader dynamic of social exclusion. People diagnosed with schizophrenia are also subject to forced drug injections, seclusion, and restraint at high rates.
The risk of violence by people with schizophrenia is small. There are minor subgroups where the risk is high. This risk is usually associated with a comorbid disorder such as a substance use disorder – in particular alcohol, or with antisocial personality disorder. Substance use disorder is strongly linked, and other risk factors are linked to deficits in cognition and social cognition including facial perception and insight that are in part included in theory of mind impairments. Poor cognitive functioning, decision-making, and facial perception may contribute to making a wrong judgement of a situation that could result in an inappropriate response such as violence. These associated risk factors are also present in antisocial personality disorder which when present as a comorbid disorder greatly increases the risk of violence.
In 2017,[needs update] the Global Burden of Disease Study estimated there were 1.1 million new cases; in 2022 the World Health Organization (WHO) reported a total of 24 million cases globally. Schizophrenia affects around 0.3–0.7% of people at some point in their life. In areas of conflict this figure can rise to between 4.0 and 6.5%. It occurs 1.4 times more frequently in males than females and typically appears earlier in men.
Worldwide, schizophrenia is the most common psychotic disorder. The frequency of schizophrenia varies across the world, within countries, and at the local and neighborhood level; this variation in prevalence between studies over time, across geographical locations, and by gender is as high as fivefold.
In 2000,[needs update] WHO found the percentage of people affected and the number of new cases that develop each year is roughly similar around the world, with age-standardized prevalence per 100,000 ranging from 343 in Africa to 544 in Japan and Oceania for men, and from 378 in Africa to 527 in Southeastern Europe for women.
Accounts of a schizophrenia-like syndrome are rare in records before the 19th century; the earliest case reports were in 1797 and 1809.Dementia praecox, meaning premature dementia, was used by German psychiatrist Heinrich Schüle in 1886, and then in 1891 by Arnold Pick in a case report of hebephrenia. In 1893 Emil Kraepelin used the term in making a distinction, known as the Kraepelinian dichotomy, between the two psychoses – dementia praecox, and manic depression (now called bipolar disorder). When it became evident that the disorder was not a degenerative dementia, it was renamed schizophrenia by Eugen Bleuler in 1908.
In the early 20th century, the psychiatrist Kurt Schneider categorized the psychotic symptoms of schizophrenia into two groups – hallucinations and delusions. The hallucinations were listed as specific to auditory and the delusions included thought disorders. These were seen as important symptoms, termed first-rank. The most common first-rank symptom was found to belong to thought disorders.[page needed][page needed] In 2013 the first-rank symptoms were excluded from the DSM-5 criteria; while they may not be useful in diagnosing schizophrenia, they can assist in differential diagnosis.
Subtypes of schizophrenia – classified as paranoid, disorganized, catatonic, undifferentiated, and residual – were difficult to distinguish and are no longer recognized as separate conditions by DSM-5 (2013) or ICD-11.
Breadth of diagnosis
Before the 1960s, nonviolent petty criminals and women were sometimes diagnosed with schizophrenia, categorizing the latter as ill for not performing their duties within patriarchy as wives and mothers. In the mid-to-late 1960s, black men were categorized as "hostile and aggressive" and diagnosed as schizophrenic at much higher rates, their civil rights and Black Power activism labeled as delusions.
In the early 1970s in the US, the diagnostic model for schizophrenia was broad and clinically based using DSM II. Schizophrenia was diagnosed far more in the US than in Europe which used the ICD-9 criteria. The US model was criticised for failing to demarcate clearly those people with a mental illness. In 1980 DSM III was published and showed a shift in focus from the clinically based biopsychosocial model to a reason-based medical model. DSM IV brought an increased focus on an evidence-based medical model.
From the 1960s until 1989, psychiatrists in the USSR and Eastern Bloc diagnosed thousands of people with sluggish schizophrenia, without signs of psychosis, based on "the assumption that symptoms would later appear". Now discredited, the diagnosis provided a convenient way to confine political dissidents.
In the United States, the annual cost of schizophrenia – including direct costs (outpatient, inpatient, drugs, and long-term care) and non-healthcare costs (law enforcement, reduced workplace productivity, and unemployment) – was estimated at $62.7 billion for the year 2002.[a] In the UK the cost in 2016 was put at £11.8 billion per year with a third of that figure directly attributable to the cost of hospital, social care and treatment.
In 2002, the term for schizophrenia in Japan was changed from seishin-bunretsu-byō (精神分裂病, lit. 'mind-split disease') to tōgō-shitchō-shō (統合失調症, lit. 'integration–dysregulation syndrome') to reduce stigma. The new name, also interpreted as "integration disorder", was inspired by the biopsychosocial model. A similar change was made in South Korea in 2012 to attunement disorder.
Media coverage reinforces public perception of an association between schizophrenia and violence; in film, people with schizophrenia are highly likely to be portrayed as a danger to others. In the UK guidelines for reporting conditions and award campaigns have shown a reduction in negative reporting since 2013.
The study of potential biomarkers that would help in diagnosis and treatment of schizophrenia is an active area of research as of 2020. Possible biomarkers include markers of inflammation, neuroimaging,brain-derived neurotrophic factor (BDNF), and speech analysis. Some markers such as C-reactive protein are useful in detecting levels of inflammation implicated in some psychiatric disorders but they are not disorder-specific. Other inflammatory cytokines are found to be elevated in first episode psychosis and acute relapse that are normalized after treatment with antipsychotics, and these may be considered as state markers. Deficits in sleep spindles in schizophrenia may serve as a marker of an impaired thalamocortical circuit, and a mechanism for memory impairment.MicroRNAs are highly influential in early neuronal development, and their disruption is implicated in several CNS disorders; circulating microRNAs (cimiRNAs) are found in body fluids such as blood and cerebrospinal fluid, and changes in their levels are seen to relate to changes in microRNA levels in specific regions of brain tissue. These studies suggest that cimiRNAs have the potential to be early and accurate biomarkers in a number of disorders including schizophrenia.
^A 2007 review stated that the 2002 estimate was still the best available, and a 2018 review cited the same $62.7 billion.
^ abcdFerri FF (2019). Ferri's clinical advisor 2019: 5 books in 1. Elsevier. pp. 1225–1226. ISBN9780323530422.
^ abJavitt DC (June 2014). "Balancing therapeutic safety and efficacy to improve clinical and economic outcomes in schizophrenia: a clinical overview". The American Journal of Managed Care. 20 (8 Suppl): S160-165. PMID25180705.
^ abParakh P, Basu D (August 2013). "Cannabis and psychosis: have we found the missing links?". Asian Journal of Psychiatry (Review). 6 (4): 281–287. doi:10.1016/j.ajp.2013.03.012. PMID23810133. Cannabis acts as a component cause of psychosis, that is, it increases the risk of psychosis in people with certain genetic or environmental vulnerabilities, though by itself, it is neither a sufficient nor a necessary cause of psychosis.
^Lawrence RE, First MB, Lieberman JA (2015). "Chapter 48: Schizophrenia and Other Psychoses". In Tasman A, Kay J, Lieberman JA, First MB, Riba MB (eds.). Psychiatry (fourth ed.). John Wiley & Sons, Ltd. pp. 798, 816, 819. doi:10.1002/9781118753378.ch48. ISBN978-1-118-84547-9.
^ abcdeKillaspy H (September 2014). "Contemporary mental health rehabilitation". East Asian Archives of Psychiatry. 24 (3): 89–94. PMID25316799.
^ abBecker T, Kilian R (2006). "Psychiatric services for people with severe mental illness across western Europe: what can be generalized from current knowledge about differences in provision, costs and outcomes of mental health care?". Acta Psychiatrica Scandinavica. Supplementum. 113 (429): 9–16. doi:10.1111/j.1600-0447.2005.00711.x. PMID16445476. S2CID34615961.
^ abcCapdevielle D, Boulenger JP, Villebrun D, Ritchie K (September 2009). "Durées d'hospitalisation des patients souffrant de schizophrénie: implication des systèmes de soin et conséquences médicoéconomiques" [Schizophrenic patients' length of stay: mental health care implication and medicoeconomic consequences]. L'Encéphale (in French). 35 (4): 394–399. doi:10.1016/j.encep.2008.11.005. PMID19748377.
^Marshall M (September 2005). "Association between duration of untreated psychosis and outcome in cohorts of first-episode patients: a systematic review". Archives of General Psychiatry. 62 (9): 975–983. doi:10.1001/archpsyc.62.9.975. PMID16143729.
^Cohen CI, Freeman K, Ghoneim D, et al. (March 2018). "Advances in the Conceptualization and Study of Schizophrenia in Later Life". The Psychiatric Clinics of North America. 41 (1): 39–53. doi:10.1016/j.psc.2017.10.004. PMID29412847.
^Lecardeur L, Meunier-Cussac S, Dollfus S (May 2013). "[Cognitive deficits in first episode psychosis patients and people at risk for psychosis: from diagnosis to treatment]". L'Encephale. 39 (Suppl 1): S64-71. doi:10.1016/j.encep.2012.10.011. PMID23528322.
^Bundy H, Stahl D, MacCabe JH (February 2011). "A systematic review and meta-analysis of the fertility of patients with schizophrenia and their unaffected relatives: Fertility in schizophrenia". Acta Psychiatrica Scandinavica. 123 (2): 98–106. doi:10.1111/j.1600-0447.2010.01623.x. PMID20958271. S2CID45179016.
^van Dongen J, Boomsma DI (March 2013). "The evolutionary paradox and the missing heritability of schizophrenia". American Journal of Medical Genetics Part B: Neuropsychiatric Genetics. 162 (2): 122–136. doi:10.1002/ajmg.b.32135. PMID23355297. S2CID9648115.
^Misiak B, Krefft M, Bielawski T, Moustafa AA, Sąsiadek MM, Frydecka D (April 2017). "Toward a unified theory of childhood trauma and psychosis: A comprehensive review of epidemiological, clinical, neuropsychological and biological findings". Neuroscience and Biobehavioral Reviews. 75: 393–406. doi:10.1016/j.neubiorev.2017.02.015. PMID28216171. S2CID21614845.
^Senkowski D, Gallinat J (June 2015). "Dysfunctional prefrontal gamma-band oscillations reflect working memory and other cognitive deficits in schizophrenia". Biological Psychiatry. 77 (12): 1010–1019. doi:10.1016/j.biopsych.2015.02.034. PMID25847179. S2CID206104940. Several studies that investigated perceptual processes found impaired GBR in ScZ patients over sensory areas, such as the auditory and visual cortex. Moreover, studies examining steady-state auditory-evoked potentials showed deficits in the gen- eration of oscillations in the gamma band.
^Young J, Anticevic A, Barch D (2018). "Cognitive and Motivational Neuroscience of Psychotic Disorders". In Charney D, Buxbaum J, Sklar P, Nestler E (eds.). Charney & Nestler's Neurobiology of Mental Illness (5th ed.). New York: Oxford University Press. pp. 215, 217. ISBN9780190681425. Several recent reviews (e.g., Cohen and Minor, 2010) have found that individuals with schizophrenia show relatively intact self-reported emotional responses to affect-eliciting stimuli as well as other indicators of intact response(215)...Taken together, the literature increasingly suggests that there may be a deficit in putatively DA-mediated reward learning and/ or reward prediction functions in schizophrenia. Such findings suggest that impairment in striatal reward prediction mechanisms may influence "wanting" in schizophrenia in a way that reduces the ability of individuals with schizophrenia to use anticipated rewards to drive motivated behavior.(217)
^Ocklenburg S, Güntürkün O, Hugdahl K, Hirnstein M (December 2015). "Laterality and mental disorders in the postgenomic age—A closer look at schizophrenia and language lateralization". Neuroscience and Biobehavioral Reviews. 59: 100–110. doi:10.1016/j.neubiorev.2015.08.019. PMID26598216. S2CID15983622.
^McGurk SR, Mueser KT, Feldman K, Wolfe R, Pascaris A (March 2007). "Cognitive training for supported employment: 2–3 year outcomes of a randomized controlled trial". The American Journal of Psychiatry. 164 (3): 437–441. doi:10.1176/appi.ajp.164.3.437. PMID17329468.
^Peters L, Krogmann A, von Hardenberg L, et al. (19 November 2019). "Long-Acting Injections in Schizophrenia: a 3-Year Update on Randomized Controlled Trials Published January 2016 – March 2019". Current Psychiatry Reports. 21 (12): 124. doi:10.1007/s11920-019-1114-0. PMID31745659. S2CID208144438.
^Heinrichs RW (2003). "Historical origins of schizophrenia: two early madmen and their illness". Journal of the History of the Behavioral Sciences. 39 (4): 349–363. doi:10.1002/jhbs.10152. PMID14601041.
^Wilson M (March 1993). "DSM-III and the transformation of American psychiatry: a history". The American Journal of Psychiatry. 150 (3): 399–410. doi:10.1176/ajp.150.3.399. PMID8434655.
^Fischer BA (December 2012). "A review of American psychiatry through its diagnoses: the history and development of the Diagnostic and Statistical Manual of Mental Disorders". The Journal of Nervous and Mental Disease. 200 (12): 1022–1030. doi:10.1097/NMD.0b013e318275cf19. PMID23197117. S2CID41939669.
^Wu EQ, Birnbaum HG, Shi L, et al. (September 2005). "The economic burden of schizophrenia in the United States in 2002". The Journal of Clinical Psychiatry. 66 (9): 1122–1129. doi:10.4088/jcp.v66n0906. PMID16187769.