俱舍論疏 15.210

15.210

論「由五因故至能令心狂」，第一因也。由六種業果令心狂也。此由因時令他失念，得異熟果心亦失念，名曰心狂。如文可解。

The Śāstra says: "Due to five causes […] they can cause the mind to become insane"—this is the first cause. It is through the fruit of six kinds of karma that the mind is caused to become insane. Because at the time of the cause one caused another to lose mindfulness, in receiving the fruit of maturation one's own mind also loses mindfulness, which is called insanity. It can be understood according to the text.