His initial research, in the 1970s, became a touchstone for studies that have since mapped the vast communications network among immune cells, hormones and neurotransmitters. It introduced a field of research that nailed down the science behind notions once considered magical thinking: that meditation helps reduce arterial plaque; that social bonds improve cancer survival; that people under stress catch more colds; and that placebos work not only on the human mind but also on supposedly insentient cells.
At the core of Dr. Ader’s breakthrough research was an insight already obvious to any grandmother who ever said, “Stop worrying or you’ll make yourself sick.” He demonstrated scientifically that stress worsens illness — sometimes even triggering it — and that reducing stress is essential to health care.
That idea, now widely accepted among medical researchers, contradicted a previous principle of biochemistry, which said that the immune system was autonomous. As late as 1985, the idea of a connection between the brain and the immune system was dismissed in an editorial in The New England Journal of Medicine as “folklore.”