Psychotropic drugs are associated with adverse effects. Mostly adverse effects are reported by patients or elicited by clinicians. For many other adverse effects, it is necessary to do baseline blood tests to avoid giving a medication to patients who are at a high risk of a particular adverse effects and to monitor blood tests to either avoid or to manage specific adverse effects. Most treatment guidelines recommend blood tests to monitor adverse effects of psychotropic drugs. However, mostly these recommendations are based on low levels of scientific evidence and expert opinions. Hence, it is not uncommon to see significant variations amongst different guidelines. Ideally, the monitoring recommendations should take in to account clinical significance and pathophysiology of the adverse effects. Moreover, before proposing any form of monitoring, we must be reasonably sure that such monitoring will be beneficial for patients and lastly monitoring should be cost effective as well. In the field of medicine, monitoring recommendations are increasingly subjected to scientific rigour. In this review, we have compared blood tests monitoring recommendations, by various national and international treatment guidelines, of commonly used psychotropic drugs such as antipsychotic drugs, lithium, and valproate. This is a narrative review, in which we have critically appraised the recommendations and highlighted the need for evidence-based monitoring of adverse effects of psychotropic drugs.