Chapter 5: Schizophrenia & Related Psychotic Disorders
Schizophrenia and the related psychotic disorders are some of the most impairing forms of psychopathology. Psychotic disorders involve many different types of symptoms that involved altered cognition and perception.
Symptoms include delusions, which are false beliefs that are often fixed, and hallucinations, which are perceptual experiences that occur without stimulus from the outside world generating them. Other symptoms include disorganized speech and behaviour, flat affect, alogia, catatonia, and lack of motivation.
Problems in cognitive functioning are a critical aspect of psychotic disorders, and a major source of disability and loss of functional capacity. These include problems with episodic memory, working memory, and processing speed. Some people with schizophrenia also show deficits in social cognition.
There are important genetic contributions to the likelihood someone will develop schizophrenia, but it is important to know there is no “schizophrenia gene.” Like most forms of psychopathology, the genetic risk for schizophrenia reflects the summation of many different genes.
Environmental factors can also increase risk of developing schizophrenia such as stress, infection, malnutrition and diabetes during pregnancy. Birth complications that cause hypoxia (lack of oxygen) are also associated with an increased risk for schizophrenia.
Using cannabis increases risk for developing psychosis, especially if you have other risk factors. The likelihood is also higher for children who grow up in urban settings and for some minority ethnic groups.
Unfortunately, none of these risk factors are specific enough to be used in a clinical setting.
An important area of research is with individuals who are at “clinical high risk,” for psychosis. These are individuals who show milder symptoms that have developed recently and who are experiencing some distress or disability. When followed over time, about 35% of these individuals develop a psychotic disorder.
Schizophrenia is treated with antipsychotic medication. Newer antipsychotics have fewer size effects. Schizophrenia is also treated with Cognitive Enhancement Therapy, which has been shown to improve cognition, functional outcome, and social cognition.