A Dissociation of the Acute Effects of Bupropion on Positive Emotional Processing and Reward Processing in Healthy Volunteers Walsh, Annabel E. L., Nathan T. M. Huneke, Randi Brown, Michael Browning, Phil Cowen, and Catherine J. Harmer. ‘A Dissociation of the Acute Effects of Bupropion on Positive Emotional Processing and Reward Processing in Healthy Volunteers’. Frontiers in Psychiatry 9 (2018). https://doi.org/10.3389/fpsyt.2018.00482.

Emotional Processing

Acute dose of bupropion produced

• slight increase in positive emotional processing
• slight increase in recognition of ambiguous faces as happy
• stronger effects on decreasing negative emotional processing
  • decrease in response bias for sad faces
  • decrease in attentional vigilance to fearful faces
  • decrease in negative bias in emotional recognition

These effects are similar to those of SSRIs and/or SNRIs. May be an early mechanism; the reversal of negative biases reduces the influence of it on the person/mood.

different actions in vitro vs in vivo - (36, 37)

bupropion, in vivo, affects firing rate of noradrenaline neurons in [[locus coeruleus]] (in rats)

Reward Processing

Bupropion may worsen [[anhedonia]] early on in treatment – because bupropion reduced likelihood of choosing high-probabillity wins in a test.

Results in healthy individuals may be different. The brain (of rats) automatically reduced cell firing

Bupropion may increase tonic levels of dopamine, but that can result decrease the responsivity of the [[dopaminergic system]] → reduces phasic firing.

This may lead to a person putting the same value on a neutral result and a win (in the game/test). Result: failure or slower to learn how a certain stimulus is associated with a high-probability win.

Longer-term studies with SSRI ([[citalopram]]) shows a beneficial effect on reward processing. This may be true for bupropion.

related:: [[antidepressants modify the reward function]]

topic:: [[bupropion]] [[phasic firing]] [[tonic firing]]