**Hye Jin Jee 1,2, Sang Goo Lee 1, Katrina Joy Bormate <sup>1</sup> and Yi-Sook Jung 1,2,\***


Received: 26 August 2020; Accepted: 4 October 2020; Published: 9 October 2020

**Abstract:** Caffeine occurs naturally in various foods, such as coffee, tea, and cocoa, and it has been used safely as a mild stimulant for a long time. However, excessive caffeine consumption (1~1.5 g/day) can cause caffeine poisoning (caffeinism), which includes symptoms such as anxiety, agitation, insomnia, and gastrointestinal disorders. Recently, there has been increasing interest in the effect of caffeine consumption as a protective factor or risk factor for neurological and psychiatric disorders. Currently, the importance of personalized medicine is being emphasized, and research on sex/gender differences needs to be conducted. Our review focuses on the effect of caffeine consumption on several neurological and psychiatric disorders with respect to sex differences to provide a better understanding of caffeine use as a risk or protective factor for those disorders. The findings may help establish new strategies for developing sex-specific caffeine therapies.

**Keywords:** caffeine; neurological and psychiatric disorders; sleep disorder; stroke; dementia; depression; sex differences
