Additive factor method applied to psychopathology with special reference to childhood hyperactivity.

A review is made of available studies using the Additive Factor Method (AFM) in clinical research. The paper argues that by using the AFM in studies of psychological dysfunctioning a major contribution can be made: first, in preventing spurious findings, second, distinguishing between group differences with and without information processing deficits, and third, by identifying fundamental processes which may be impaired. This may offer psychodiagnostics an empirical basis on which to define disorders. This paper reviews studies contributing to this endeavour. It further raises the question of how to interpret clinical research, which is conducted in the tradition of information processing but not within the frame of reference of the AFM. It is suggested that such research is useful and complementary to that conducted using the AFM. Further, it is suggested that the role of energetical factors in clinical disorders and in their treatment is an important area for future experimental clinical research.