Lecture 6: Personality and Mental Health Flashcards
personality
enduring pattern of thinking, feeling, and behaving
models of personality
- five factor model (OCEAN)
- HEXACO (has 6 traits but theyre pretty similar to FFM)
FFM
O - openness to experience C - conscientiousness E - extraversion A - agreeableness N - neuroticism
Which traits are positively assoc with leadership roles
O, C, E
Why is there unlikely to be aggressive selection for extreme values of any trait
trade offs exist for all extreme phenotypes
ex. extreme extraversion = mating success, exploration of env but also physical risks and family stability probz
Which traits are positively associated with reproductive fitness?
E + assoc in men, N and A + assoc in men and women.
- OPENESS is negatively associated
Heritability of FFM traits
around 0.42 to 0.57 (same thing for HEXACO traits)
Most GWAS hits for which FFM traits
N, E, O (most interesting and most related to neuro disorders)
- serotonin receptor and dopamine receptor subtype often studied
5-HTT gene
codes for serotonin transporter
- short allele associated with low expression and thus low uptake. (not super legit tho)
DRD4 variations
sequence length polymorphism (VNTR) with 2 to 8 repeats
- 2-5 repeats is the short allele
- 6-8 repeats is long allele (associated with reduced DA sensitivity)
- variants associated with novelty seeking, travel, immigration, social behaviour, and disorders
- associated with increased sexual drive, as well as infidelity, sexual promiscuity, and interest in a variety of sexual behaviours
Review: GCTA
genome wide complex trait analysis
- compares the chance similarity in all common SNPs between biologically unrelated individuals
- if a trait is driven by SNPs, individuals sharing those SNPs should be more similar in terms of traits
SNPs can, at best, explain
10-20% of variation in traits
Missing heritability
for any trait, part of the total variability is explained by genetics (genetic variation, Vg = ~ 50%) and only a small portion of that is explained by SNPs (like 10%). The missing heritability is the variation due to genetics that is not accounted for by SNPs
Genetic influences are greatest when relationship with parents is
positive.
- lower levels of conflict
Heritability of religiosity and conservatism
- relig h2 = 0.3 - 0.45
- conservatism h2 = 0.5 - 0.65
both increase with age (can’t inherit specific religion tho)
Genetics and ideology
Correlation between DZ twins decreases after leaving home but not with MZ twins
Monogamous mating strategy
One partner. Reasons could include:
- genetics
- dopamine, oxytocin, vasopressin systems
- sociological forces (which may in turn be a selection pressure)
- in primitive cultures, monogamy may have guaranteed the parentage of the child
AVP1aR gene variants
linked to extra-pair mating in women and marital status in men (more 334 alleles)
also associated with altruism?? more altruism in adults, less in children (hard to reconcile these studies)
altruism
voluntary behaviour for the benefit of another individual with a clear benefit
- is a form of prosocial behaviour studied in the lab
HERITABLE 0.3 to 0.5
Oxytocin variations
linked to various social behaviours in adults and children
- modifications in gene structure (epigenetic effect) can occur with aversive experiences, altering brain function and social behaviour in the long term
h2 of mental health disorders
BP > SZ > familial AD > Panic disorder > MDD > GAD
anxiety in those of low motivation correlates with… but in those of high motivation, moderate anxiety can
….reduced performance
…improve performance
Same deal with working memory (low WM and anxiety = worse, high WM and anxiety = better)
Genes for depression
- enriched in hypothalamus (stress axis) and PFC (emotion regulation)
- experience-dependent modifications of certain genes (epigenetic) following early life adversity may increase depression risk
Pharmacogenetics
using genetics to predict how a person will respond to a certain drug (best fit)
Anorexia
affects 1% of population, but 90% of cases are female
- h2 of eating disorders is 0.3 - 0.7??
- STRONG ROLE OF ENV
- genetic basis: thought that gene environment interaction occurs at same time as external pressures emerge
Addiction/ substance abuse
Popular definition: complex brain disease in which there is compulsive engagement in a behaviour despite knowledge of harmful consequences
- h2 hovers around 0.5 give or take
Risk factors for addiction
- stability of home env
- gender (higher rates in males for certain addictions)
- mental health status
- early use and peer groups
- genetics
Mesocortical and mesolimbic pathway
dopamine variants
reward is correlated with release of DA in the NAcc. Dysfunction in this pathway may contribute to control disorders
- genes associated with the receptor and the hydroxylase are associated with increased risk for addictive disorders
Alcohol metabolism in addiction
gene variants for aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) are associated with poor alcohol tolerance and reduced risk of alcoholism (why drink somethng that makes you violently ill)
FFM traits and substance abuse correlations
N and O assoc with higher use, A and C assoc with lower usage rates
FFM traits vs HEXACO
same except FFM has neuroticism and HEXACO has honesty-humility and emotionality
Genetic correlations between FFM and disorders
- C negatively associated with most disorders except anorexia
- O positively correlated with most disorders (SZ, BPD, MDD)
- neuroticism pos assoc with MDD
- extraversion pos assoc with ADD
