Effects of a hops (Humulus lupulus L.) dry extract supplement on self-reported depression, anxiety and stress levels in apparently healthy young adults: a randomized, placebo-controlled, double-blind, crossover pilot study - Kyrou, I; Christou, A; Panagiotakos, D; Stefanaki, C; Skenderi, K; Katsana, K; Tsigos, C (Hormones (Athens), 2017)