This chapter presents available studies in the context of pharmacogenomics and pharmacokinetics relevant to the treatments employed for mental disorders. The two major groups of mental disorders explored are schizophrenia and major depressive disorder (MDD). The under-representation of African populations in these studies is remarkable. An international collaboration is needed to increase the involvement of African populations in such studies. The chapter also discusses the recent advances in antidepressant pharmacogenetic decision support tools, as a promising approach to provide personalised treatment recommendations during patient consultations. In conclusion, it is important to direct future research towards better understanding of the genetic risk for mental disease incidence, treatment efficacy, and risk of toxicity/adverse effects in potentially under-represented groups such as African populations.