A recent systematic review has investigated the effectiveness of Vitex agnus castus (VAC) in the treatment of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD). 
PMS is estimated to effect 20-30% of women, whilst 2-8% of all women suffer from a more severe form of PMS, called premenstrual dysphoric disorder (PMDD). [2,3,4] Whilst symptoms are similar, severity is the defining factor in PMDD, which manifests as marked emotional distress, impacting patient functioning in some individuals. [2,5]
Researchers analysed eight randomised clinical trials that used VAC in the treatment of PMS or PMDD. All eight studies demonstrated positive therapeutic outcomes for VAC supplementation in PMS or PMDD.  Furthermore, VAC was well-tolerated with only mild or transient side-effects. 
VAC was shown to be superior to placebo in randomised controlled trials. When comparing VAC to active treatment, VAC was more effective than pyridoxine (B6) in treating PMS symptoms but not as efficacious as fluoxetine in alleviating the psychological symptoms of PMS. 
In evaluating the dosage and administration of VAC extract, 20mg of VAC was found to be the optimum dosage whilst the use of VAC in the six days before menses only was found to be most efficacious. [6,7]
VAC extract was found to be a safe and valid alternative in the treatment of PMS and PMDD symptoms, however longer studies are warranted to investigate the long-term safety and efficacy of VAC. 
1. Cerqueira, R., Frey, B., Leclerc, E. et al. (2017). Vitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic review. Arch Womens Ment Health, (20), 713-719.
2. Vigod, S., Frey, B., Soares, C., Steiner, M. (2010). Approach to premenstrual dysphoria for the mental health practitioner. Psychiatr Clin North Am, (33), 257-272.
3. Dueñas, J., Lete, I., Bermejo, R. et al (2011). Prevalence of premenstrual syndrome and premenstrual dysphoric disorder in a representative cohort of Spanish women of fertile age. European Journal of Obstetrics and Gynecology and Reproductive Biology, 156 (1), 72 – 77.
4. Yonkers, K., O’Brien, P., Eriksson, E. (2008). Premenstrual syndrome. Lancet, (371), 1200-1210.
5. Delara, M., Ghofranipour, F., Azadfallah, P., Tavafian, S. S., Kazemnejad, A., & Montazeri, A. (2012). Health related quality of life among adolescents with premenstrual disorders: a cross sectional study. Health and Quality of Life Outcomes, 10 (1).
6. Schellenberg, R., Zimmermann, C., Drewe, J., Hoexter, G., Zahner, C. (2012). Dose-dependent efficacy of the Vitex agnus castus extract Ze 440 in patients suffering from premenstrual syndrome. Phytomedicine, 19 (14), 1325-1331.
7. Zamani, M., Neghab, N., Torabian, S. (2012). Therapeutic effect of Vitex agnus castus in patients with premenstrual syndrome. Acta Med Iran, 50 (2), 101-106.
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