The National Institutes of Health uncovered a host of serious violations in risky experiments on schizophrenics by Mount Sinai and the affiliated Bronx Veterans Affairs hospital.

Violations included failing to fully inform patients of the risks and intentionally inducing psychotic behavior in patients who had been doing well, the feds said.

The scathing report said that in one of the three federally funded studies in the 1980s and early '90s, researchers halted anti-psychotic medications that were helping schizophrenics and then gave them L-dopa, which results in psychosis in the mentally ill.

"Subjects ... suffered at least some short-term harm or discomfort as evidenced by documentation of schizophrenia relapse in all 28 cases," according to the nine-page letter from the federal Office for the Protection from Research Risks, a division of NIH.

One of the patients who was removed from medication for a month grew violent and hit a doctor, while another experienced suicidal thoughts, the federal investigation of the 1987 research project found.

A third patient's symptoms "worsened significantly" just one day after being taken off his or her usual medication.

Despite the incidents, none of the patients suffered a severe relapse or long-term harm, the agency found.

Vera Hassner Sharav, an advocate for the mentally ill, lodged the complaint five years ago that prompted the federal probe.

"Experiments such as these violate every code of medical ethics," said Hassner Sharav, president of Citizens for Responsible Care in Psychiatry and Research.

"They are cruel, inhumane and scientifically unsound."

A spokesman for Mount Sinai Medical School said the facility has implemented new procedures to better protect mentally ill patients - and the experiments in question have ended.

Meanwhile, state lawmakers, religious leaders and advocates for the mentally ill demanded the state scrap plans to permit risky drug experiments on psychiatric patients who aren't able to consent.

The attack, at a legislative hearing on mental-health issues, focused on a state Health Department task-force report, uncovered last month by The Post.

The report proposed rules for experiments on adult schizophrenics, manic-depressives, Alzheimer's victims and other vulnerable patients.

The panel recommended that the Health Department permit drug and other experiments of "slight" risk on patients who aren't able to agree to take part and who would not benefit from the experiments.

"We are very concerned about experimenting on individuals who are incapacitated and cannot give consent," said John Kerry, executive director of the state Catholic Conference, at a hearing of the joint Assembly-Senate finance committee.