The third defect of the mind, Karanapatavam means weakness or debility of the instruments. This weakness affects both the inner instrument, Antahkarana and the external instrument, the sense organs. (ICS , p. 84)

It must however be noted that the ailments of the external instruments have an adverse effect on the internal instruments, because of their relatedness. Anyway, the net effect of Karanapatavam as a whole, is to undermine Manavatva - human nature. (ICS , p. 86)