Hypochondria

Hypochondria is a psychological condition where a person experiences abnormal and chronic anxiety over imagined illnesses.

Reginald Barclay suffered from hypochondria, as did William Telfer. It could be treated with medicine or counseling. 

In 1996, when Tuvok refused to removed his shirt and experience 20th century weather, Tom Paris commented, "Vulcans. Deep down you're all a bunch of hypochondriacs." In Photons Be Free, the holonovel written by the USS Voyager's EMH, the character based on Harry Kim, Kymble, was a hypochondriac. 

Hipocondria