Stress in early life is known to precipitate anxiety and mood disorders. Studies have found that the hypothalamic-pituitary-adrenal (HPA) axis disruptions are instrumental in the pathogenesis of these disorders. Patients with anxiety and mood disorders endure hyperactivity of the HPA axis. 

The effects of various anxiolytic agents, for instance – benzodiazepines like clonazepam and SSRIs, on the HPA axis have been investigated. Clonazepam reduces the activity of corticotrophin-releasing factor (CRF) neurons in the hypothalamus. While SSRIs, like Escitalopram are potent anxiolytics that act by modulating the HPA axis.

Escitalopram inhibits CRF release in the central nucleus of the amygdala and also increases the glucocorticoid receptor (GRs) density in the hippocampus and hypothalamus.

Thus, Escitalopram and Clonazepam express molecular effects on regulation of the HPA axis, which explains their clinical efficacy.