Short-term SSRI treatment normalises amygdala hyperactivity in depressed patients.
BACKGROUND
Antidepressant drugs such as selective serotonin re-uptake inhibitors (SSRIs) remediate negative biases in emotional processing in depressed patients in both behavioural and neural outcome measures. However, it is not clear if these effects occur before, or as a consequence of, changes in clinical state.


METHODS
In the present study, we investigated the effects of short-term SSRI treatment in depressed patients on the neural response to fearful faces prior to clinical improvement in mood. Altogether, 42 unmedicated depressed patients received SSRI treatment (10 mg escitalopram daily) or placebo in a randomised, parallel-group design. The neural response to fearful and happy faces was measured on day 7 of treatment using functional magnetic resonance imaging. A group of healthy controls was imaged in the same way.


RESULTS
Amygdala responses to fearful facial expressions were significantly greater in depressed patients compared to healthy controls. However, this response was normalised in patients receiving 7 days treatment with escitalopram. There was no significant difference in clinical depression ratings at 7 days between the escitalopram and placebo-treated patients.


CONCLUSIONS
Our results suggest that short-term SSRI treatment in depressed patients remediates amygdala hyperactivity in response to negative emotional stimuli prior to clinical improvement in depressed mood. This supports the hypothesis that the clinical effects of antidepressant treatment may be mediated in part through early changes in emotional processing. Further studies will be needed to show if these early effects of antidepressant medication predict eventual clinical outcome.
University Department of Psychiatry, Warneford Hospital, Oxford, UK.
B R
BR
Godlewska
R
R
Norbury
S
S
Selvaraj
P J
PJ
Cowen
C J
CJ
Harmer
D000328:Adult; D000679:Amygdala / Q000187:drug effects* / Q000503:physiopathology*; D001288:Attention / Q000187:drug effects; D016022:Case-Control Studies; D015283:Citalopram / Q000008:administration & dosage*; D003865:Major Depressive Disorder / Q000188:drug therapy* / Q000503:physiopathology*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004644:Emotions / Q000187:drug effects; D005149:Facial Expression; D005239:Fear / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000187:drug effects* / Q000502:physiology*; D012016:Reference Values; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage*; D055815:Young Adult
D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors