Background <p>Psychiatric disorders are associated with significant disability, and patients sometimes respond partially to conventional therapies.</p> Objectives <p>Purpose of the present manuscript is to summarize the available literature on the effectiveness of high-intensity interval training (HIIT) in patients affected by mental conditions. The primary research question is whether HIIT can improve the symptoms of various psychiatric conditions, possibly in augmentation to standard therapies.</p> Methods <p>The review was conducted following the PRISMA guidelines adapted for scoping reviews. A bibliographic search was conducted on the following database sources: Pubmed, Embase and Scopus. English-language publications about HIIT intervention in adult patients with mental disorders were reviewed. Fourteen studies met the inclusion criteria and were finally included in this review.</p> Results <p>HIIT contributes to reduce the global severity of illness of several psychiatric conditions, with an effectiveness at least comparable to other non-pharmacological approaches (effect size d range: 0.36–2.10). Most studies regard patients affected by schizophrenia or depressive disorders.</p> Conclusions <p>HIIT may be considered a complementary option to improve symptoms of several psychiatric conditions. More studies are needed to identify the best patient profile for this protocol.</p>