Lecture 2: Neurobiological Risk Factors Flashcards
1
Q
Twin studies on ASB
A
- Heritability ranges from 0.4-0.5
- Stable across different measurement e.g. teacher report
2
Q
Different forms of ASB
A
- Reactive aggression = heritability 0.39 e.g. frustration
- Proactive aggression = heritability 0.50 e.g. instrumental to achieve a goal
- Meta analysis of 103 studies on aggressive ASB (H=0.65) vn non-aggressive (H=0.48) = strong genetic influence
- -> BUT heritability of ASB is strongest for early onset
3
Q
Twin study: violent crime
A
-Violent crime heritability = 0.54
4
Q
Adoption studies
A
Mednick et al (1984)
- 14,427 adoptees in Denmark
- Sig positive correlation between adopted and biological parents for convictions of property
- BUT not true with respect to violent crimes
5
Q
Candidate genes: Brunner syndrome
A
- Brunner et al (1993) noticed 5 family males all antisocial (NOTE FOR GEORGIA: A FEMALE NOTICED THAT THE MALES WERE ANTISOCIAL)
- Analysed urine sampleS
- Identified mutation in warrior gene - MAOA
- Brunner syndrome associated with mutation in MAOA - gene changed glutamine to a termination codon
- MAO-A enzyme degrades amine neurotransmitters
- Theres MAOA-L and MAOA-H
- MAOA-L associated abnormal levels of serotonin –> aggressive behaviour
6
Q
MAOA study - interaction
A
- Genotyped large sample
- Maltreatment measured in childhood
- Looked at male individual from sample
- Found gene (MAOA-L) X environment interaction (maltreatment)
7
Q
Birth complications
A
Mednick et al (1959-1961)
- Tested biosocial interaction hypothesis = birth complications combined with maternal rejection predisposes to adult violent crime
- 4269 males from birth
- Complications at age 0
- Early maternal rejection age 1
- Violent crimes at 18
- Birth complications combined with early maternal deprivation increased risk of adult crime
- When only rejected least percentage committed crimes, but small group that did commit performed most violent
8
Q
Mechanisms that can explain interaction between birth complication and social risk - study
A
- Guinea pig study
- Looked at hypoxia = deprivation of o2 during birth
- Looked at neuronal density
- Ones exposed to hypoxia had reduced neuronal density in cortical and sub cortical structures (hippocampus, cingulate and cortex)
- Reduced grey matter at hippocampus after 7 and 28 days
- Hypoxia = decreased white matter integrity
- Birth complications set in motion structural brain problems
9
Q
Drinking in pregnancy
A
- Foetal alcohol syndrome (FAS) = exposure to alcohol pre-natally
- 4 features:
1. Exposure to alcohol during pregnancy
2. Craniofacial abnormalities
3. Growth retardation
4. Central nervous dysfunction (learning disabilities and low IQ)
10
Q
Facial features of children with FAS
A
- Small head
- Short nose
- Thin upper lip
11
Q
FAS associated with psychiatric disorders study
A
- Over 5000 studies
- Looked at with psychiatric disorders associated with FAS
- CD = most common (90%)
12
Q
Mechanisms that underlines relationship between FAS and antisocial behaviour
A
- Impacts corpus callosum
- Damages to hippocampus = impairs learning and memory
- Associated with poor executive functions
13
Q
Structural brain: study of antisocial behaviour
A
- Glenn and Raine (2014)
- Man with rumpus compressing ventral medial prefrontal cortex
- Was school teacher then acted inappropriately with children
- Operated on –> back to normal
- Tumour came back and behaviour returned
14
Q
Antisocial personality disorder symptoms
A
- Impulsivity
- Recklessness
- Repeated criminal acts
- Lack of remorse
- Poor decision making
15
Q
Biology of ASPD
A
- Abnormalities with vmPFC
- Lesions with vmPFC –> changes in behaviour and personality regardless of age
Meta analysis:
- Looking at relationship between grey matter volume and CD
- Subdivided PFC into different regions
- Demonstrated that individuals with CD had grey matter reduction in several regions of PFC, orbit-frontal cortex, dPFC, internal cingulate cortex
