Psychotropic as needed or pro re nata (prn) medications, particularly antipsychotics and benzodiazepines, are commonly prescribed, which is not evidence-based. This paper aims to suggest a set of answers to the question why is this practice common. A critical comparative inquiry approach and conceptual analysis are used, addressing psychopharmacology (psychotropic medications), neurostimulation/ neuromodulation, psychotherapy and psychiatric rehabilitation as the four main types of clinical intervention in contemporary psychiatry. Key findings are that psychotropic prn medications may be commonly prescribed primarily due to coercive behavior towards people with psychosis in the case of antipsychotics and due to insufficient access to evidence-based psychosocial interventions such as cognitive behavioral therapy (CBT) in the case of Benzodizapines. This paper is limited by the dearth of rigorous evidence published in relation to psychotropic prn medications. Psychotropic prn medication may be prescribed for unacceptable reasons. Rigorous research is needed to study reasons for prescribing psychotropic prn medications as well as their cost-benefit, preferably using well-controlled comparisons with psychosocial (and other) evidence-based interventions such as CBT.