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

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.

To investigate the effect of a single dose of an SSRI on the amygdala response to emotional faces.

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.

Volunteers treated with citalopram displayed a significantly reduced amygdala response to fearful facial expressions compared with placebo.

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.