clinical depression

NOUN
19 LETTERS · STARTS WITH C

clinical depression is a valid 19-letter word worth 25 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
C3L1I1N1I1C3A1L1D2E1P3R1E1S1S1I1O1N1
3 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 0 + 2 + 1 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 =25 PTS
DOUBLE WORD → 50TRIPLE WORD → 75
MEANING

What does clinical depression mean?