Neural sensitivity to eudaimonic & hedonic rewards differentially predict adolescent depressive symptoms over time

Samantha Rhoads on Adriana Galván
1 November 2017

Intro to Eudaim/hed(onic) Rewards

Hedonia can hurt humans while eudaimonia can encourage excellence.

  • Historically: Aristotle promoted eudaimonia over hedonia

  • Hedonic Rewards (humans gravitate here): pleasure seeking

    • desire, personal extrinsic gains, self-focused
    • food, sex, TV, music

  • Eudaimonic Rewards: prosocial rewards

    • charity, generosity
    • meaning & purpose

Intro: Adolescence & Rewards

  • Galván: we don't know about rewards & adolescence!
  • Adolescence is a time of flux
    • more vulnerability
  • Propensity for risk-taking
    • sometimes adaptive - social relationships
    • sometimes detrimental - drugs
  • Brevity of research on eudaim/hed(onic) rewards during adolescence
    • reward processing & implications on well-being
    • what might be beneficial?
  • Depressive symptoms rise in adolescence

Deeper into Adolescence & Eudaim/hed(onic) Rewards

  • Hedonic rewards: salient in adolescence
    • impulsivity
  • Ventral Striatum is active during reward-processing
  • Reward processing, dopaminergic dysregulation, risk, & disorders
    • vulnerability when unstable encoding of rewards
    • SO response to rewards impacts well-being small

Ventral Striatum & Rewards

  • Reward processing associated with the ventral striatum (VS) activation
    • VS & “liking”
  • Can be measured independently of participants' consciousness
  • Heightened VS activity during:
    • hedonic rewards?
    • eudaimonic rewards? small

Intro: Overall Study Design

  • longitudinal!
    • 2 timepoints: changes in depressive symptoms
  • fMRI ROI analysis of VS activation during rewards/risk-taking tasks
    • Task 1: eudaimonic vs. hedonic small
    • Task 2: risky hedonic decisions for reward small

Methods: Sample & Timepoints

  • T1: 47 adolescents (15-17 y/o)
    • Task 1 & 2 –> fMRI
    • Depressive symptoms
  • T2: 39 adolescents
    • Depressive symptoms

small

Methods: Breakdown of Measures/Tasks

  1. Self-report questionnaire about depressive symptoms
  2. fMRI paradigms
    • Task 1: Family Donation Task
    • CD… YOU + $$, FAM = ±0 (40 trials)
    • PR… YOU - $$, FAM + $$ (24 trials)
    • Control… Random/Practice (24 trials)
    • Task 2: Risk-Taking Task
    • BART: pump balloon –> more $$ –> risk explosion (no payout)
    • total game earnings in cash

Results: Depressive Variability

  • T2 controlling or T1: change in depression
    • variability in change: some increase, some decrease
  • T1 depression ≠ T2 depression (ns)
  • T2 depression ~ T1 depression (sig)
  • T1 depression ~ Gender (ns)
  • Sex difference in depressive changes
    • Females: increase (ms)
    • Males: decrease (ms)
  • Conclusion: Control for gender in analyses!

Results: VS Activation: Eudaimonic Rewards & Depression

  • T1, VS, depression (ns)
  • T2 Depression ~ VS activation + T1 Depression (sig)
  • Ps: High CD –> BIGGEST longitudinal decrease in depression (relative to PR)
  • High CD + High VS = reduced depression (sig)
  • High PR + High VS = increased depression (sig) small

Results: VS Activation: Hedonic Rewards & Depression

  • T1, VS, depression (ns)
  • risky VS ~ depression (sig) small

Results: VS Activation: Depression ~ Eudaimonic & Hedonic Rewards Independently

  • CD VS ~ risky VS (ns)
  • CD VS ~ PR VS (ns)
  • PR VS ~ risky VS (sig)

  • risky VS ~ depression (sig)

  • all conditions VS ~ T2 depression + T1 depression
    • depression change (controlling for T1)
  • VS to eudaim/hed(onic) rewards explain 58% variance in T2 depression
    • sex on 1%

Discussion

  • Eudaimonic: optimal well-being
  • Adolescents w/ stronger VS activation when making prosocial decisions showed longitudinal DECLINES in depressive symptoms
    • not for T1 though
  • Adolescents w/ stronger VS activation when making hedonic/risky rewards showed longitudinal INCREASES in depressive symptoms
  • Well-being might depend on higher values: family, morality, culture
  • What next? Providing opportunities for adolescents to cultivate eudaimonic feelings
  • Different types of rewards might mean different outcomes: neural responses might be risk factors & protective factors at the same time

Discussion: Limitations

  • Small sample
    • attrition
    • Ps chose < 7 trials: excluded
  • Lab setting
  • Narrow age-range
  • No PC, CR analyses included

Discussion: Future Research?

  • Well-being might depend on higher values: family, morality, culture
  • What next? Providing opportunities for adolescents to cultivate eudaimonic feelings
  • Different types of rewards might mean different outcomes: neural responses might be risk factors & protective factors at the same time
  • Motivational systems should be assessed