Martin Katz in an undated photo. (Courtesy of the Katz family)

Martin Katz, one of the first researchers to study the action of antidepressants on mentally ill patients and a key figure in the history of the National Institute of Mental Health, died Jan. 12 at a nursing home in Rockville, Md. He was 89.

The cause was cardiomyopathy, said his daughter, Nancie Katz.

Trained as a clinical psychologist, Dr. Katz was most comfortable as a researcher. His broad background — his primary interest early in life was chemistry — allowed him to see the need for collaboration between behaviorists and biologists when it came to understanding the roots of mental illness.

In college, when color-blindness prevented him from being able to identify reactions in the chemistry lab, he chose to concentrate instead on psychology. In retrospect, his personal disappointment was science’s gain.

In 1957 Dr. Katz applied his analytical skills to his role as executive secretary for a research advisory committee at the National Institutes of Health, which was looking to fund collaborative studies into psychotropic medications. Those drugs were just reaching the commercial market in the mid-1950s and would radically transform the treatment of mental illness. It was also one of NIH’s first forays into the biology of psychopathology and lead to the founding of a new discipline that Dr. Katz helped establish: neuropsychopharmacology.

As psychiatry became increasingly medicalized, Dr. Katz remained a believer in a multi-dimensional approach to mental illness. He thought the link between behavioral symptoms and neurotransmitter systems was an important and underappreciated area of study. His scientific acumen, applied to psychology, yielded the most profound results.

Although he never practiced clinical psychology, Dr. Katz developed two critical tools still used today for evaluating psychiatric patients in treatment: the Katz Adjustment Scales, which measures the complex social, emotional and behavioral changes in patients before and after treatment; and the multivantage model of measurement, a method for assessing patients that includes not only professionals, but the patient and family as well.

“Marty Katz was a revolutionary,” said psychologist Anthony Marsella, a friend and former colleague. “He was advancing our knowledge of depression . . . through an integrated effort to explain the complexities of psychopathology through its biological, psychological, behavioral and sociocultural origins.”

Martin M. Katz — whose middle initial stood for nothing — was born in Brooklyn on Aug. 6, 1927, and was the oldest of three sons of a haberdasher and a saleswoman. He graduated from Brooklyn College in 1949 with a degree in psychology and chemistry, then received his PhD in clinical psychology from the University of Texas at Austin in 1955.

In post-doctoral research, he contributed to a study that showed how ascorbic acid raised cognitive acuity in malnourished Latino children — a study later used by chemist and Nobel laureate Linus Pauling to prove the power of nutrition and Vitamin C.

The bulk of Dr. Katz’s career was spent at the National Institute of Mental Health where, among other roles, he was chief of its clinical research branch from 1968 to 1978.

Between 1975 and 1992, Dr. Katz was involved in a number of projects for the World Health Organization, one of which took him to Nigeria, where he helped establish that country’s first institute of neuropsychiatry. From 1984 to 1994, he was a professor and chief of the division of psychology in the department of psychiatry at the Albert Einstein College of Medicine/Montefiore Medical Center in New York.

Among other honors, Dr. Katz receivedan award last year for distinguished service fromthe American College of Neuropsychopharmacology, where he had been an active member for more than 50 years.

Dr. Katz, who resided in Bethesda, Md., is survived by his wife of 66 years, Barbara Gelb Katz; two children, Nancie Katz of Brooklyn and Pete Katz of Austin; and two granddaughters.

In the 1960s, Dr. Katz co-wrote a paper on the psychological effects of the hallucinogen LSD, which was briefly a subject of clinical study. The results, he said in an interview shortly before his death, were “ambiguous,” and follow-up research was never funded by the government.

Nonetheless, Dr. Katz was fascinated enough by the drug that he took it himself, monitored by a psychiatrist friend, to try to better understand its effects.

“It knocked the pins out of me,” he told The Washington Post in December. “It’s almost as if your whole neurological pattern is upset, comes apart, and your system goes back a level, to a more primitive level.”

In the end he didn’t learn much, he said, but the experience had a profound effect on him: “It just shakes your whole foundation as to what you think you understand about the brain.”