Primary fears of this kind are fear of contracting HIV infection (AIDS phobia or HIV serophobia),[3] pulmonary tuberculosis (phthisiophobia),[4] sexually transmitted infections (syphilophobia or venereophobia),[5] cancer (carcinophobia), heart diseases (cardiophobia[6]), COVID-19 (coronaphobia), and catching the common cold or flu.
[11] There are sometimes checking behaviors, such as examining the body for lesions that could be Kaposi's sarcoma seen in AIDS patients or spots that could be skin cancer.
[10][11] One theorized cause of nosophobia in medical students detailed in Hunter et al.'s study is based around psychodynamic theory.
[12] Any pre-existing "weaknesses, sensitivities or idiosyncrasies" react to the stresses and intense focus on the body, disease, and death that medical studies bring.
[9] One theory is that younger siblings are raised by an older family and are therefore more likely to experience illness and death of ageing relatives.
Younger siblings are more likely to report having coddling, overprotective parents (especially mothers), who show distress at injury or sickness, while also providing the reward of care and attention.
[10] Methods used included exposure to phobic stimuli, satiation (such as writing down fears in detail) and paradoxical intervention (such as exercising to "bring on a heart attack").
[1][10] Some authors have suggested that the symptoms seen in medical students should be referred to as "nosophobia" rather than "hypochondriasis", because the quoted studies show a very low percentage of hypochondriacal character of the condition.
Early research found that at least 70% of medical students at McGill University experience nosophobia at some point during their undergraduate degrees.
[12] Further research found that 79% of a random sample of medical students at the University of Southern California had a history of the phobia.