Mitochondria are membrane-enclosed organelle found in most eukaryotic cells, where they generate the majority of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition, they are involved in a range of other processes, such as signalling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several neuropsychiatric disorders, in particular, depression, anxiety, schizophrenia, autism, and Alzheimer's dementia. Furthermore, the presence of mutations at the level of mitochondrial or nuclear DNA (mtDNA and nDNA, respectively) has been linked to personality disorders, behavioral disturbances, thought alterations, impulsivity, learning impairment, cognitive failures until dementia. The aim of this paper is to review the literature on the relationship between psychiatric symptoms or syndromes and mtDNA mutations or mitochondrial alterations, while highlighting novel therapeutic targets for a broad range of disorders.