From the article: A brain region known as the amygdala could play a key role in predicting symptom improvement following ketamine therapy in patients with treatment-resistant anxious depression, according to new research published in the Journal of Affective Disorders.

“Since the antidepressant effects of ketamine in patients with anxious depression remain unclear, it is necessary to investigate the potential biomarkers predicting the antidepressant efficacy of ketamine in patients with anxious depression,” said study author Bin Zhang of the Affiliated Brain Hospital of Guangzhou Medical University.

“Previous studies have pointed out that functional connectivity differences in the amygdala are linked to depression improvement after ketamine treatment in depressed patients, but their role in anxious depression patients is uncertain. Therefore, we investigated the correlation between depression improvement after ketamine treatment and amygdala functional connectivity in anxious depression patients.”

For their study, the researchers examined neuroimaging data from 31 patients with anxious depression and 18 patients with non-anxious depression.

The researchers only included participants who had a diagnosis of major depression without comorbid psychotic symptoms, had a score greater than 17 on the Hamilton Depression Rating Scale, had previously failed to improve after at least two antidepressant treatments, had completed fMRI brain scans, and had undergone six ketamine infusions.