Gene/environment interactions in the development of mental health and illness Flashcards Preview

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Flashcards in Gene/environment interactions in the development of mental health and illness Deck (7)
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1
Q

What are gene-environment interactions?

A
  • Gene-environment interaction (GxE) is a causal mechanism where one or more genetic variants and one or more environmental factors contribute to the causation of a condition in the same individual.
  • In a GxE, the genetic factors influence the sensitivity to environmental exposures.
  • GXE are distinguished from gene-environment correlations, where genetic factors influence the probability of environmental exposures.
2
Q

Are GxE important in the causation of mental illness?

A

Yes

  • Individuals differ in their vulnerability to pathogens
  • There is variably degeneracy of complex biological systems
  • There is a paradox between heritable disorders and reproductive disadvantage
  • Paradox of low shared environment estimates in twin studies and strong specific environmental risk factors
  • These two paradoxes cause attributable risk of environment and genetic factors to sum up to more than 100%.
  • There may be a large genetic risk for an illness, but it is imperceptible due to reproductive disadvantage (eg. autism)
  • There are KNOWN environmental risk factor for mental illness (eg. cannabis use in adolescents)
3
Q

What are two good reasons for studying GxE?

A
  • Dispeling myth of genetic (or social!) determinism

- Targeted/personalized interventions

4
Q

How does childhood maltreatment effect Monoamine oxidase A and antisocial behaviour?

A

Maltreatment leads to low MAO-A activity, which is associated with antisocial behaviour and adversity.

5
Q

How is serotonin transporter linked to stress and depression? Childhood maltreatment?

A

Serotonin transporter is upregulated with more stressful life events. This is also linked to a risk of developing major depression episodes.

Childhood maltreatment also linked with upregulated transporter and risk of major depression. Support attenuates this effect.

6
Q

How can childhood abuse and neglect lead to chronic depression?

A

Maltreatment leads to

  • Reduced quality of intimate relationships
  • Stressful life events and difficulties (affecting BDNF)
  • Self esteem issues

These converge to cause onset depressive episodes. Perpetuation of onset depression can cause chronic depression. Through GxE childhood abuse and neglect facilitates this perpetuation (through increased 5-HT reuptake etc.)

7
Q

How does the amino acid sequence of BDNF correlate with depression onset?

A

ValVal: lower rates of depression. Seen with low stressful life events.

ValMet: Higher rates of depression

MetMet: Extremely high rates of depression. Seen with many stressful life events.