The focus of this chapter is to discuss how rational it can be to use multiple psychiatric medications in combinations to treat an individual patient and what are the basic principles to follow when doing so. This matter is put in the context of the rest of medicine where multiple medication use (MMU) can be based on a highly sophisticated rationale based on knowledge of the pathoetiology and pathophysiology of the illness being treated (e.g., Human Immuno Deficiency Virus- HIV) to a less sophisticated rationale because of limited understanding of the nature of the illness (e.g., bipolar disorder). In this regard, all diagnoses in medicine including psychiatry can be grouped into four hierarchical levels of understanding ranging from least sophisticated (symptomatic diagnoses) to the most sophisticated where pathoetiology and pathophysiology are known. Parenthetically, the goal of medicine as a field is to achieve the highest level of diagnostic sophistication possible to improve their ability to treat or alter the course of the disease. Unfortunately, most psychiatric diagnoses are still at the syndromic level and hence psychiatric medications are typically aimed at the alleviation of sign and symptoms of these disorders. Moreover, two related phenomena are increasing the frequency and complexity of MMU in psychiatry. The first is the increase in the number and types of psychiatric medications available: Since 1990, the Food and Drug Administration (FDA) approved almost 40 new psychotropic drugs to treat a variety of psychiatric illnesses. Second, the ability to rationally designed psychopharmaceuticals has further increase the potential, perhaps the need and perhaps the rationale behind psychiatric MMU. Nevertheless, until knowledge of the pathoetiology and pathophysiology of psychiatric diagnoses progresses beyond the syndromic level, the rationale underlying psychiatric MMU will remain more limited than is ideal.
Khan, A. Y., & Preskorn, S. H. (2013). Multiple psychiatric medications use in psychiatry: How rational can it be? In Polypharmacy in Psychiatry Practice Volume I: Multiple Medication Use Strategies (pp. 3–24). Springer Netherlands. https://doi.org/10.1007/978-94-007-5805-6_1