The co-occurrence of two psychiatric diagnoses in one person is called what?

• A. Dualism
• B. Monotony
• C. Syndysis
• D. Comorbidity

Answer: (D)

Comorbidity means two or more psychiatric diagnoses occurring in the same person, either at the same time or across different times, with potential interactions that influence how the conditions present and how they should be treated. In mental health care, this reflects the real-world possibility that disorders often overlap—depression and anxiety, for example, or mood disorders with substance-use disorders—so clinicians plan integrated care that addresses all active conditions.

Other terms don’t fit this clinical idea. Dualism is about the mind–body relationship in philosophy, not about co-occurring diagnoses. Monotony isn’t a medical term for psychiatric conditions. Syndysis (or syndesis) refers to a union or connection in a different medical sense and isn’t used to describe the co-occurrence of psychiatric disorders.