I hear or see this occasionally.

Problem:
This is a mispronunciation or misspelling of a valid noun.

Explanation:
The valid noun is “hypochondria” — spelled H-Y-P-O-C-H-O-N-D-R-I-A.

This noun means excessive concern about one’s health, especially focusing on symptoms that could be due to cardiac or gastric problems.

The noun “hypochondria” exemplifies the value of knowing the roots of words in the English language.

The “chondria” portion of the noun refers to ensiform cartilage — that is, to sword-shaped or xiphoid cartilage, which relates to the lowermost segment of the three segments that comprise the sternum.

The “hypo” portion of the noun means under or below.

Knowing these two roots makes it easy to understand how the noun “hypochondria” refers in particular to cardiac or gastric problems.

So replacing “hypo” with “hyper” produces a nonsense word. Whatever is over or above the xiphoid cartilage is outside the body and therefore could not refer to gastric or cardiac problems.

For fun, I searched Google for each of the following (with the quotation marks, to avoid variations) and got about the indicated numbers of matches:

• “hypochondria” — spelled H-Y-P-O-C-H-R-O-N-D-R-I-A — 456,000 matches
• “hyperchondria” — spelled H-Y-P-E-R-C-H-R-O-N-D-R-I-A — 1,760 matches

This tells me that Web authors have favored the correct word over the incorrect word by a ratio of 259-to-1, which is excellent.

Solution:
“Hypochondria”