12. Psychosis

Question 1

What is “psychosis”? How can it be caused?

Answer 1

Presence of hallucinations or delusions (i.e. symptoms, not diagnosis) - multiple causes, e.g.

• delirium caused by infection
• acute drug/alcohol intoxication
• hyperthyroidism
• encephalitis
• medications, e.g. steroids, L-dopa

Question 2

What is a hallucination? What is a delusion?

Answer 2

Hallucination = perception without a stimulus, can be in any sensory modality

Delusion = unshakeable abnormal belief, outside of cultural norms

Question 3

Describe the 5 1st rank symptoms of schizophrenia.

Answer 3

1. AUDITORY HALLUCINATIONS, e.g.
   - thought echo (hearing thoughts aloud)
   - running commentary (voices referring to P in 3rd person and conversing with each other about the P)
2. PASSIVITY EXPERIENCES: P believes an action or feeling is caused by an external force (e.g. MI5)
3. THOUGHT WITHDRAWAL: thoughts are being taken out of mind, e.g.
   - thought broadcast (thoughts being made known to others, e.g. via radio)
   - thought insertion (thoughts being implanted by others)
4. DELUSIONAL PERCEPTIONS: attribution of new meaning, usually in sense of self-reference, to a normally perceived object
5. SOMATIC HALLUCINATIONS: mimic feelings from inside the body (e.g. snake in abdomen)

Question 4

What is the difference between positive and negative symptoms in schizophrenia?

Answer 4

Positive: added symptoms, e.g. delusions, hallucinations, thought disorder, lack on insight

Negative: take away from P, e.g. low motivation, social withdrawal, self-neglect

Question 5

Describe the 5 types of schizophrenia.

Answer 5

1. PARANOID SCHIZOPHRENIA
   - delusions or hallucinations prominent
2. HEBEPHRENIC SCHIZOPHRENIA
   - weird, giggly, child-like
   - definite and sustained flattening or shallowness of affect, or incongruity/inappropriateness or affect, aimless and disjointed behaviour or thought disorder affecting speech
   - hallucinations/delusions must not dominate
3. SIMPLE SCHIZOPHRENIA
   - loss of drive and interest, aimlessness, idleness, self-absorbed attitude and social withdrawal
   - marked decline in social, academic or work performance
   - no hallucinations/delusions
4. CATATONIC SCHIZOPHRENIA
5. UNDIFFERENTIATED SCHIZOPHRENIA
   - insufficient symptoms to meet criteria of any subtype, or many symptoms fitting >1 criteria

Question 6

Which NT is thought to be involved in schizophrenia? Explain how.

Answer 6

Dopamine pathways:

1. Mesocortical pathway - from ventral tegmental area to frontal cortex and cingulate gyrus. Thought to be underactive in SZP.
2. Mesolimbic pathway - from ventral tegmental area to limbic structures (amygdala, septal area and hippocampal formation). Thought to be overactive in SZP.

Question 7

Describe the autoimmune hypothesis of SZP.

Answer 7

Based on anti-NMDA encephalitis: antibodies, e.g. after viral infection or ovarian teratoma, bind to NMDA receptor causing internalisation and hypofunction

Question 8

Describe the medications used in SZP management.

Answer 8

Act to regulate dopamine:

1. typical antipsychotics (e.g. chlorpromazine) - block D2 Rs in all CNS dopamineric pathways, mainly mesolimbic and mesocortical but others areas also so many side effects
2. atypical antipsychotics (e.g. haloperidol) - lower affinity for D2 Rs so milder side effects