When a Congressional investigation revealed in June that Dr. Joseph Biederman, a world-renowned child psychiatrist, had earned far more money from drug makers than he had reported to his university, he said that his interests were “solely in the advancement of medical treatment through rigorous and objective study.”

But e-mail messages and internal documents from Johnson & Johnson made public in a court filing reveal that Dr. Biederman pushed the company to finance a research center at Massachusetts General Hospital, in Boston, with a goal to “move forward the commercial goals of J.& J.” The documents also show that the company prepared a draft summary of a study that Dr. Biederman, of Harvard, was said to have written.

Dr. Biederman’s work helped to fuel a fortyfold increase from 1994 to 2003 in the diagnosis of pediatric bipolar disorder and a rapid rise in the use of powerful, risky and expensive antipsychotic medicines in children.

Although many of his studies are small and often financed by drug makers, Dr. Biederman has had a vast influence on the field largely because of his position at one of the most prestigious medical institutions.