Psychological Disorders: Schizophrenia

Study Notes

A class of disorders marked by delusions, hallucinations, disorganized thinking, disorganized motor behavior, and negative symptoms.
Prevalence estimates suggest that schizophrenia occurs in about 0.7% of the population, with variation by ethnicity and country.
Psychotic features typically emerge between late teens and mid-30s, with peak onset for males in mid-20s and for females in late-20s.

Delusions: false beliefs maintained despite being clearly out of touch with reality (e.g., believing one is a tiger or that private thoughts are broadcast to others).
Distorted perception: hallucinations are sensory perceptions that occur in the absence of a real, external stimulus or are gross distortions of perceptual input (e.g., hearing voices).
Disorganized thinking: problems in goal-directed behavior, leading to difficulties in performing activities of daily living.
Disorganized or abnormal motor behavior: catatonic behavior is a decrease in reactivity to the environment, and may include staring, grimacing, and echoing of speech.
Negative symptoms: two types, especially prominent in schizophrenia, including diminished emotional expression and reduced speech production.

Broad range of cognitive deficits, including attention, working memory, and other executive functions, semantic memory, social cognition, and language.
Cognitive impairment is stable and independent of positive symptoms, and strongly determines functional outcome.
Cognitive impairment as an endophenotype: a potential marker of genetic risk for schizophrenia.

Social cognition deficits in schizophrenia, including social withdrawal, false attribution of harmful intentions to others, and difficulties in interpreting verbal language.
Social cognition deficits predict onset of psychosis in individuals at high-risk of developing schizophrenia.

Do not yet know the single cause of schizophrenia.
Not due to a single cause, but rather a combination of genetic and environmental factors.
Neurodevelopmental hypothesis of schizophrenia: prevailing theory, suggesting that schizophrenia is a disorder of faulty brain development.

Family history of schizophrenia.
Social factors: urban birth, migrant status, and low social class.
Pre/perinatal factors: obstetric complications, winter birth, maternal influenza, maternal malnutrition, and rhesus incompatibility.
Postnatal factors: early childhood CNS infection, epilepsy, learning disability, delayed milestones, poor childhood peer relationships, early cannabis use, and life events.

Smaller cortex overall, less grey matter than white, enlarged ventricles, smaller thalamus, temporal lobes, and prefrontal cortex.
Not an effect of medication, with similar findings in unaffected first-degree relatives of patients.