Bacopa monnieri as augmentation therapy in the treatment of anhedonia, preclinical and clinical evaluation.

Bacopa monnieri (L.) is widely used in Ayurvedic medicine as a neural tonic for improving intelligence and memory. Several studies highlighted its efficacy in neuropsychiatric diseases but there is no evidence regarding anhedonia. Aim of the present work was to preclinically and clinically test against anhedonia a standardized B. monnieri extract (20% bacosides). In a mouse model of a depressive-like syndrome induced by lipopolysaccharide (LPS), the daily administration of the extract (50-200 mg kg^-1 , p.o.) for 1 week, dose-dependently counteracted the immobility time in Porsolt and Tail suspension tests (p < .01). At the sucrose preference test (directly related to the ability for feeling pleasure) the extract treatment (100 and 200 mg kg^-1 ) counteracted the reduction of sucrose intake induced by LPS (p < .01). Moreover, B. monnieri significantly reduced cytokines, cortisol, and artemin LPS-dependent alterations in plasma while increased the brain-derived neurotrophic factor levels (p < .05). The efficacy of the same extract was tested in a clinical study in which 42 patients with significant degree of anhedonia (evaluated as Snaith-Hamilton Pleasure Scale [SHAPS] score ≥ 3) were enrolled. Patients were divided into two groups and treated with citalopram or citalopram associated with B. monnieri (300 mg bid) for 4 weeks. The Pears Sample T-test showed a significant improvement (p < .05) in relevant scales (Hamilton depression rating scale, SHAPS, and strength and difficulties questionnaire) in the extract-treated group in comparison to citalopram alone was recorded. These data suggest that B. monnieri extract may be effective for the management of anhedonia and therefore should be considered for future controlled trials.