intrusive thought와 rumination의 차이

Although direct comparison studies are needed, it is likely that unwanted intrusive thoughts can be quite easily distinguished from rumination. Rumination represents a much longer train of thought that is recurrent, repetitive, cyclical, highly ego-syntonic, past oriented, and directed. Unwanted intrusions, on the other hand, are brief, sudden, and somewhat unexpected thoughts or images, of relatively short duration, often ego-dystonic, and undirected by the individual. It may be that the repeated occurrence of a similar type of unwanted intrusive thought or image could trigger an episode of depressive rumination.

Intrusive Thoughts in Clinical Disorders: Theory, Research, and Treatment, 16-7쪽.