Association between testosterone levels and mood disorders: A minireview

Background: Although many studies reported the neuropsychiatric involvement of testosterone (T) levels in the development of mood disorders, its role in this disabling disorder is still not well understood. Therefore, in this review, we aim to summarize the current literature exploring serum testosterone levels in both major depressive disorder (MDD) and bipolar disorder (BD), with particular attention given to the possible causal relationship between pathological mood alterations and T levels.Methods: We selected 9 original studies from a bibliographic search on PubMed, excluding studies on hormonal therapy and other psychiatric disorders other than mood disorders.Results: The results reported by the reviewed studies were conflicting especially with regards to the presence of dysfunctional levels of T in patients with BD. Specifically, while MDD was found to be associated with low levels of T compared to healthy controls (HC), in BD the results were highly heterogeneous, with a mixed picture of reduced, increased or no difference in T levels in BD patients compared to HC.Limitations: Studies were highly heterogeneous in terms of samples employed, psychometric scales used for assessing depressive symptoms, T assay methods and therapeutic regimens.Conclusions: Overall, T levels were shown to be reduced in both MDD and BD patients, ultimately suggesting that T could be useful as a biomarker in mood disorders and provide guidance for future research.