In 2007, Ohsawa and colleagues reported that molecular hydrogen (H2) gas significantly reduced the
infarct volume size in a rat model of cerebral infarction, which was, at least, partially due to scavenging hydroxyl
radicals. Since then, multiple studies have shown that H2 has not only anti-oxidative but also anti-inflammatory
and anti-apoptotic properties, which has ignited interest in the clinical use of H2 in diverse diseases. A growing
body of studies has indicated that H2 affects both mental and physical conditions. Mental disorders are characterized
by disordered mood, thoughts, and behaviors that affect the ability to function in daily life. However,
there is no sure way to prevent mental disorders. Although antidepressant and antianxiety drugs relieve symptoms
of depression and anxiety, they have efficacy limitations and are accompanied by a wide range of side effects.
While mental disorders are generally thought to be caused by a variety of genetic and/or environmental
factors, recent progress has shown that these disorders are strongly associated with increased oxidative and inflammatory
stress. Thus, H2 has received much attention as a novel therapy for the prevention and treatment of
mental disorders. This review summarizes the recent progress in the use of H2 for the treatment of mental disorders
and other related diseases. We also discuss the potential mechanisms of the biomedical effects of H2 and
conclude that H2 could offer relief to people suffering from mental disorders.