The exact underlying causes of nosophobia are poorly understood, but it is thought to be multifactorial, involving a combination of genetic, environmental, and social factors. There may be genetic factors that predispose the individual to develop mental health conditions (e.g., obsessive-compulsive disorder) or specific phobias, like nosophobia. For example, individuals with a known family history of a specific phobia have an increased risk of developing a phobia compared to individuals without a family history. Previous traumatic experiences with illness or illness-related hospitalizations may also contribute to the development of nosophobia. It has also been proposed that a person may develop a specific phobia through modeling, or observing a reaction from another person and internalizing this fear.
Additionally, other risk factors for nosophobia include stress, certain personality traits (e.g., perfectionism), a history of obsessive-compulsive disorder, caring for a loved one with a serious illness, and those in the healthcare profession. Nosophobia may also be associated with other specific phobias including cardiophobia (i.e., fear of heart disease or heart attacks), pharmacophobia (i.e., fear of medications), and carcinophobia (i.e., fear of getting cancer), among others.