Psychosis and Schizophrenia

What is psychosis?

Inability to distinguish internal mental experiences from external reality.

Approximate prevalence of psychosis?

~1% of the population.

Typical age of onset for psychosis?

Males: teens–mid 20s; Females: teens–late 20s.

Why is prevalence difficult to assess?

Symptoms vary, overlap with other disorders, and are context-dependent.

What is the emotional impact of psychosis?

High distress for individuals and families.

What is a hallucination?

A false sensory perception without an external stimulus.

Most common type of hallucination?

Auditory

Auditory hallucinations are linked to which brain area?

Left temporal lobe activity.

Other types of hallucinations?

Visual, olfactory, gustatory, tactile, nociceptive, thermoceptive, proprioceptive.

Which disorders besides schizophrenia can include hallucinations?

Bipolar disorder, MDD, PTSD, personality disorders.

What is a delusion?

Fixed, false belief held despite clear contradictory evidence.

Difference between bizarre and non-bizarre delusions?

Bizarre = implausible; Non-bizarre = possible but unsupported.

What are primary delusions?

Sudden, incomprehensible beliefs without emotional explanation.

What are secondary delusions?

Beliefs understandable in context of mood or circumstances.

Most common type of delusion?

Persecutory delusions.

What are referential delusions?

Belief that neutral events/media refer personally to the individual.

What are grandiose delusions?

Beliefs of exceptional power, identity, or importance.

What is erotomania?

Belief that another person is in love with the individual.

What are somatic delusions?

False beliefs about bodily functions or appearance.

What is delusional parasitosis?

Belief of being infested with parasites.

What is disorganised thinking?

Non-linear or illogical thought patterns.

Examples of disorganised thought?

Circumstantiality, tangentiality, word salad.

What are disorganised behaviours?

Inappropriate, unpredictable, or catatonic actions.

What are negative symptoms?

Loss or reduction of normal functioning.

Key negative symptoms to remember?

Avolition, alogia, anhedonia, flat affect, psychomotor retardation.

When do negative symptoms commonly appear?

Prodromal phase of schizophrenia.

Five core symptom domains of schizophrenia?

Delusions, hallucinations, disorganised speech, disorganised behaviour, negative symptoms.

DSM-5 diagnostic requirement (symptoms)?

≥2 symptoms for ≥1 month (one must be delusions, hallucinations, or disorganised speech).

Duration requirement for schizophrenia?

Continuous disturbance ≥6 months.

Functional requirement for diagnosis?

Impairment in ≥1 major life area.

Three classic schizophrenia subtypes?

Paranoid, catatonic, hebephrenic (disorganised).

Key twin study and findings?

Gottesman & Shields (1972):
MZ twins 42%, DZ twins 9% concordance.

Which symptoms show stronger genetic links?

Negative symptoms

Core idea of dopamine hypothesis?

Dopamine dysregulation, not simply excess dopamine.

Where is dopamine activity increased?

Striatal regions

How do most antipsychotics work?

Block dopamine D2 receptors.

Early biological risk factor?

Perinatal complications (≈5× increased risk).

Substance most strongly linked to psychosis risk?

Cannabis

Social groups at highest risk?

Low socioeconomic status populations.

Key stressful life events linked to onset?

Bereavement, job loss, relationship breakdown.

What is Expressed Emotion (EE)?

High criticism, hostility, emotional over-involvement in families.

Neurodevelopmental model summary?

Early brain disruptions → cognitive/social deficits → stress/drugs → dopamine dysregulation.

First-episode psychosis treatment?

Early intervention services + antipsychotics + CBT/family work.

Treatment for later acute episodes?

Crisis/home treatment teams + meds + psychological therapy.

Most effective psychological interventions?

Family interventions, psychoeducation, CBT.

Main limitation of current treatments?

Side effects and limited relapse-prevention evidence.