Vitamin D deficiency may be a clinical problem in patients with addictions. The authors systematically searched for studies addressing vitamin D and addiction and develop a hypothesis which can direct future research of the possible mechanistic role of vitamin D in the process of addiction.

Systematic review of the literature found in PubMed and EMBASE followed by narrative review combined with clinical experiences leading to hypotheses for future research.

Only five articles were identified about a role of vitamin D in the pathophysiology of addiction. Their results are in line with a possible influence of vitamin D in dopaminergic transmission. The cerebral vitamin D status depends on the functionality of genetic variants of vitamin D receptor and other involved genes. Routine serum calcidiol levels may not adequately reflect cerebral vitamin D status. Uncertainty exists regarding appropriate calcidiol blood levels and proper dosages for affecting the central nervous system (CNS).

The putative pathophysiological role of vitamin D in substance abuse has been insufficiently studied which calls to more studies how to measure cerebral vitamin D status in clinical practice. Research is indicated whether vitamin D supplementation should use higher dosages and aim to reach higher calcidiol serum levels. Measuring dopaminergic functioning within the prefrontal cortex as reflected by neuropsychological tests selected as suitable could be a appropriate proxy for the cerebral vitamin D status when studying the pharmacogenomics of this functionality in patients.