Effect of a single dose of citalopram on amygdala response to emotional faces

BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) are typically thought to have a delay of several weeks in the onset of their clinical effects. However, recent reports suggest they may have a much earlier therapeutic onset. A reduction in amygdala responsivity has been implicated in the therapeutic action of SSRIs. AIMS: To investigate the effect of a single dose of an SSRI on the amygdala response to emotional faces. METHOD: Twenty-six healthy volunteers were randomised to receive a single oral dose of citalopram (20 mg) or placebo. Effects on the processing of facial expressions were assessed 3 h later using functional magnetic resonance imaging. RESULTS: Volunteers treated with citalopram displayed a significantly reduced amygdala response to fearful facial expressions compared with placebo. CONCLUSIONS: Such an immediate effect of an SSRI on amygdala responses to threat supports the idea that antidepressants have an earlier onset of therapeutically relevant effects than conventionally thought.