Dr. Paul Janssen, 77; Founded International Pharmaceutical Firm

Dr. Paul Janssen, 77, the founder of an international pharmaceutical company known for its development of several important anti-psychotic drugs, died Tuesday at a hotel in Rome, where he had been attending a meeting. His home was in Vosselaar, Belgium. The cause of death was not disclosed.

Janssen founded his own research laboratory in his native Belgium in 1956; it later became Janssen Pharmaceutica, which eventually had 16,000 employees worldwide, including 1,000 at its U.S. headquarters in Titusville, N.J. In 1961, it merged with Johnson & Johnson.

Among the prescription drugs developed by his company was Haldol, which revolutionized the treatment of schizophrenia after its introduction in 1958. It enabled psychotic patients who had been institutionalized to live at home. The company also developed Risperdal, one of the most prescribed anti-psychotic drugs in the country; Duragesic, a skin patch for relieving moderate to severe pain; and Nizoral, an anti-fungal agent found in anti-dandruff shampoo.

Janssen, who held more than 100 patents for drugs and other inventions, studied medicine at the Catholic University of Louvain and Ghent University in Belgium. He earned a postdoctoral degree in pharmacology in 1956 at Ghent, and also studied at the Institute of Pharmacology at the University of Cologne.

He worked as managing director of his company until his retirement a few years ago.