Ms. Kneller said the doctors had been referred to a university conflict committee for review.

Mr. Grassley sent letters on Wednesday to Harvard and the health institutes outlining his investigators’ findings, and he placed the letters along with his comments in The Congressional Record.

Dr. Biederman is one of the most influential researchers in child psychiatry and is widely admired for focusing the field’s attention on its most troubled young patients. Although many of his studies are small and often financed by drug makers, his work helped to fuel a controversial 40-fold increase from 1994 to 2003 in the diagnosis of pediatric bipolar disorder, which is characterized by severe mood swings, and a rapid rise in the use of antipsychotic medicines in children. The Grassley investigation did not address research quality.

Image Senator Charles E. Grassley pushed three experts in child psychiatry at Harvard to expose their income from consulting fees. Credit... J. Scott Applewhite/Associated Press

Doctors have known for years that antipsychotic drugs, sometimes called major tranquilizers, can quickly subdue children. But youngsters appear to be especially susceptible to the weight gain and metabolic problems caused by the drugs, and it is far from clear that the medications improve children’s lives over time, experts say.

In the last 25 years, drug and device makers have displaced the federal government as the primary source of research financing, and industry support is vital to many university research programs. But as corporate research executives recruit the brightest scientists, their brethren in marketing departments have discovered that some of these same scientists can be terrific pitchmen.

To protect research integrity, the National Institutes of Health require researchers to report to universities earnings of $10,000 or more per year, for instance, in consulting money from makers of drugs also studied by the researchers in federally financed trials. Universities manage financial conflicts by requiring that the money be disclosed to research subjects, among other measures.

The health institutes last year awarded more than $23 billion in grants to more than 325,000 researchers at over 3,000 universities, and auditing the potential conflicts of each grantee would be impossible, health institutes officials have long insisted. So the government relies on universities.