Hericium erinaceus, commonly known as Lion's Mane mushroom, has garnered scientific interest for its potential neuroprotective and neurotrophic effects, which may have implications for mood disorders like depression. Several preclinical studies (in vitro and in animal models) have demonstrated that compounds in Hericium, such as hericenones and erinacines, can stimulate nerve growth factor (NGF) synthesis and support neurogenesis. These effects are thought to influence brain plasticity and resilience, factors relevant to depression.

Small human studies have also been conducted. A notable pilot study in 2010 (Nagano et al.) investigated the effects of Lion's Mane supplementation in menopausal women and found minor but statistically significant improvements in mood and reductions in depressive symptoms over four weeks. However, these studies are limited by small sample sizes, short durations, and lack of replication.

There is currently insufficient high-quality clinical evidence to conclusively support Hericium as a treatment for depression. Most evidence comes from animal research and pilot human studies, so the overall strength of evidence is rated as low (2/5). Larger, rigorous clinical trials are needed to establish efficacy and safety for this specific indication.

In summary, while early research is promising and suggests a possible scientific basis, Hericium's use for depression should be considered experimental at this time.