Hypochondriasis

Hypochondriasis or hypochondria is a condition in which a person is inordinately worried about having a serious illness. An old concept, its meaning has repeatedly changed due to redefinitions in its source metaphors. It has been claimed that this debilitating condition results from an inaccurate perception of the condition of body or mind despite the absence of an actual medical diagnosis. An individual with hypochondriasis is known as a hypochondriac. Hypochondriacs become unduly alarmed about any physical or psychological symptoms they detect, no matter how minor the symptom may be, and are convinced that they have, or are about to be diagnosed with, a serious illness.

Question: can you convince yourself you have a disease
Answer: yes