There is a common link between all these but still they are not entirely the same.

Nosophobia: Someone with nosophobia is afraid of developing a specific disease. The disease they fear is often chronic, life-changing or life-threatening. They may think they already have symptoms or are at greater risk of getting the disease than they are. Feared diseases may include cancers, multiple sclerosis, sexually transmitted diseases (STDs) and HIV/AIDS.

Hypochondria: Illness anxiety disorder (IAD) is the medically correct term for hypochondria. A person with IAD has worries about getting or being sick from many different diseases. They don’t fixate on one particular illness. Instead, they worry about various ailments ranging from a cold to cardiovascular disease.

Somatic symptom disorder: A person with somatic symptom disorder obsessively worries about their health — just like someone with nosophobia or IAD. However, they have actual physical symptoms of an illness but no diagnosable cause.