The comorbidity of mental and physical health problems is well-established, especially when illness becomes chronic. Comorbidity is defined as the coexistence of multiple medical conditions in a single individual, and it is a complex and widespread phenomenon that does not simply involve the addition of two or more diseases independently following their usual outcomes. Instead, it involves their interaction with each other, potentially worsening the prognosis of all present diseases and leading to an increasing number and severity of complications. This phenomenon often poses unique challenges in terms of identification, management, and treatment. Several lines of evidence have demonstrated that physical and psychological symptoms increase together and are presented in a bidirectional manner. Over the past two decades, the prevalence of comorbid mental and physical diseases has increased dramatically.