affective disorder

NOUN
18 LETTERS · STARTS WITH A

affective disorder is a valid 18-letter word worth 30 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
A1F4F4E1C3T1I1V4E1D2I1S1O1R1D2E1R1
1 + 4 + 4 + 1 + 3 + 1 + 1 + 4 + 1 + 0 + 2 + 1 + 1 + 1 + 1 + 2 + 1 + 1 =30 PTS
DOUBLE WORD → 60TRIPLE WORD → 90
MEANING

What does affective disorder mean?