schizophrenia

Question 1

What is schizophrenia?

Answer 1

A severe mental disorder suffered by 1% of the worlds population, more
common in men, impairing contact with reality and insight

Question 2

How is schizophrenia classified

Answer 2

ICD10= 2 or more negative symptoms, for 1 month

DSM5= at least 1 positive symptom and another, for 1 month, social dysfunction 6 months

(no substance abuse)

Question 2

What are the negative symptoms of schizophrenia?

Answer 2

Avolition=reduced motivation to carry out activities to achieve a result. (poor hygiene, lack of persistence in work, lack of energy)

Speech poverty= reduced amount/ quality of speech delay in responses during a conversation

Question 2

What are the positive symptoms of schizophrenia?

Answer 2

Hallucinations= Hearing voices or seeing things which aren’t there, may relate to environment or have no relationship

Delusions= Irrational beliefs about something that’s not logical. May believe a part of them is under external control

Question 3

Evaluate the reliability of the DSM and ICD:

Answer 3

• inter-rater reliability Cheniaux et al, 2 psychiatrists independently diagnose 100 patients using DSM and ICD.
  1: DSM= 26 ICD= 44
  2: DSM= 13 ICD= 24

Question 3

Evaluate the validity of the DSM and ICD:

Answer 3

DSM- Rosenhan
- 8 confeds, pseudopatients, 12 different hospitals, hallucinations “empty, hollow, thud”, all diagnosed, once on ward stopped symptoms, there for 2 months. however situational factors, less risky to diagnose then not

Comorbidity= 2 or more conditions, may be just 1, Buckley et al, 50% depression, PTSD 29%, OCD 23%. Sim et al 32% of 142 additional disorder

Symptom overlap= same symptoms as other conditions, bipolar has delusions & avolition. difficult to distinguish

Question 4

Gender bias and cultural bias in diagnosis of schizophrenia:

Answer 4

Gender bias:
Longenecker= since 80’s, men diagnosed more than women.
Cotton et al= women higher functioning than men (work, family) masked symptoms

Culture bias:
Afro-Caribbean 7x more likely diagnosed than white people. E.g hearing voices of ancestors acceptable in African cultures.
Escobar= white psychiatrists over-interpret symptoms of black people (distrust)

Question 5

What is the genetic basis of schizophrenia

Answer 5

Schizophrenia runs in families

Gottesman: risk of sz,
MZ= 48%
DZ= 17%
siblings= 9%
parents= 6%
relationship between sz and genetic similarity

Gottesman & Shields:
5 twin studies, 75% concordance rate for MZ twins with severe sz

Question 6

What are candidate genes?

Answer 6

• genes associated with risk of inheritance, sz is polygenic
• Ripke et al, previous data genome studies, 37,000 patients, 113,000 controls, 108 genetic variations associated with sz (dopamine)

Question 7

What is the dopamine hypothesis?

Answer 7

• dopamine implicated in the symptoms of sz
• Hyperdopaminergia
  high levels dopamine in subcortex (Brocas area) assocaited with speech poverty
• Hypodopaminergia
  Goldman-Rakic et al low levels dopamine in prefrontal cortex, negative symptoms

Question 8

What are neural correlates?

Answer 8

Measurements of structure/ activity in the brain correlating with an experience (schizophrenia)

Question 9

Neural correlates of negative symptoms:

Answer 9

• Abnormality of ventral striatum involved in avolition (loss of motivation)
• Juckel et al, measured levels of ventral striatum, found lower levels in sz than in controls, (negative correlation) therefore is a neural correlate

Question 10

Neural correlates of positive symptoms:

Answer 10

• Allen et al, low levels in superior temporal gyrus in auditory hallucination group compared to control when identifying recorded speech as theirs/others