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Schizophrenia

Schizophrenia is a disorder characterised by chronic or recurrent psychosis, often with impairments in social and occupational functioning. It's a common disorder in psychiatry and a major cause of disability worldwide. The prevalence is approximately 1%, and it affects men slightly more often than women.

The name comes from the Greek words "to split" (schizo) and "mind" (fren).

Etiology

The etiology and pathogenesis of schizophrenia is unknown, but it's believed that it may be a syndrome of multiple diseases with similar signs and symptoms, rather than a single disease. It's known that a complex interaction between genetic factors and environmental factors are involved. There is significant concordance, showing a significant genetic component.

Cigarette smoking and cannabis are known environmental risk factors, as are childhood adversities and immigration. Those who have a valine-valine polymorphism in the COMT enzyme are at especially high risk for schizophrenia if they use cannabis.

Clinical features

Schizophrenia is characterised by positive symptoms, negative symptoms, affective symptoms, and cognitive symptoms.

The positive symptoms are symptoms which are called as such because they're abnormally present (they're absent in healthy people) or an exaggeration of normal processes. These are the psychotic symptoms and include:

  • Hallucinations
  • Delusions
  • Disorganised behaviour and speech

The negative symptoms are symptoms which are abnormally absent or an absence of normal processes. These include:

  • Lack of emotional and facial expression (flat affect/apathy)
  • Social withdrawal
  • Anhedonia (inability to find pleasure)
  • Lack of motivation
  • Neglected personal hygiene

The affective (mood) symptoms include:

  • Depressive episodes
  • Postpsychotic depression
  • Suicidal behaviour

There are also cognitive symptoms, reflecting impairment in several areas, including:

  • Processing speed
  • Attention
  • Memory

People with schizophrenia often have many psychiatric comorbidities, including depression, anxiety disorders, substance use disorders, and suicidal behaviour.

Types

Schizophrenia has classically been categorised into several types, of which paranoid schizophrenia is the most common:

  • Paranoid schizophrenia – primarily has paranoid delusions
  • Disorganized schizophrenia – primarily has disorganized behaviour, speech, and emotional expression
  • Catatonic schizophrenia – catatonia is a predominant symptom
  • Undifferentiated schizophrenia – has features of multiple subtypes
  • Residual schizophrenia – patient has had a psychotic episode, but has now only negative symptoms and no positive symptoms

However, the most current version of the DSM (DSM-5-TR) and the next version of ICD (ICD-11) drop this categorisation on the reasoning that they were difficult to distinguish. They don't separate schizophrenia into types at all.

Diagnosis

The diagnosis of schizophrenia is clinical. The diagnostic criteria depends on whether one follows the ICD or DSM. According to the DSM-5, the following criteria must be met:

  • Positive symptoms with or without negative symptoms for most of the time for 1 month and 6 months of symptoms overall
  • The patient must be functioning below a normal level of functioning (at work, at home, interpersonally, etc.)
  • The patient has been drug-free for a longer amount of time (to rule out the symptoms being drug-induced)
    • The amount of time which must pass after exposure to a substance known to cause psychosis to set the schizophrenia diagnosis is not well defined, ranging between 1 and 6 months

Treatment

The mainstay of treatment for schizophrenia is antipsychotic medication, primarily second-generation ones. Treatment is usually lifelong. The choice of antipsychotic can be guided by making use of their side effects. For example, if agitation is a problem, antipsychotics with sedating effects (like olanzapine) can be used. If insomnia is a problem, antipsychotics with sedating properties (like quetiapine) can be used. Clozapine is the most efficacious antipsychotic, but due to potentially life-threatening side-effects, it's never the first choice.

Medication adherance is a major issue with these patients, and many patients with schizophrenia will eventually stop taking the drug, which usually leads to a relapse and hospital admission. Many antipsychotics exist in injectable depot-form, which are administered once a month, making adherence easier.

Because these patients are often psychotic and are therefore often unable to make medical decisions for themselves, detention and coercion is often necessary to treat them.

Psychosocial interventions, including cognitive training, cognitive-behavioural therapy, etc., are important adjunctive therapies for schizophrenia.

Electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) are possible options for treatment-resistant schizophrenia. ECT may be used for catatonic schizophrenia and TMS may be used for acoustic hallucinations in schizophrenia.