Comorbidity

In medicine, comorbidity is the simultaneous presence of two or more medical conditions in a person, most often used to describe conditions that occur alongside a primary condition being studied or treated. The term comes from a Latin root meaning sickness combined with the prefix for togetherness, and it covers both physical and psychological conditions, such as depression occurring alongside an anxiety disorder. Comorbidity is distinguished from the related concept of multimorbidity, which considers multiple co-occurring diseases without singling out one as the primary condition, and comorbidity remains especially useful in pharmaceutical research and other settings organized around a single index condition.