The large representation of mental illness among conscripts in World War II shattered the image of the nation's mental health, leading to surges in the training of psychiatrists and the establishment of research centers in psychiatric hospitals. In 1956, Sidney Merlis was appointed to develop a research program at the Central Islip Psychiatric Center in Long Island, a hospital that cared for tens of thousands of the mentally ill. The promise of electroencephalography fascinated psychiatry in the 1940s and his first studies were of the clinical and EEG effects of mescaline, when enthusiasm for simulating psychosis by hallucinogens (LSD, anticholinergics) offered an experimental approach to understanding the paranoia and hallucinations of the severely mentally ill. When chlorpromazine appeared, he demonstrated its clinical benefits and its behavioral and EEG antagonism to hallucinogens. Merlis's research center was one of the first 15 awardees when Jonathan Cole and the Psychopharmacology Service Center established the Early Clinical Drug Evaluation program in 1960 (Fink, 2000). He was a founding member of both the ACNP (1961) and the CINP (1962).

Sid explored the clinical and EEG effects of benzodiazepines, thiothixene, aspirin, L-dopa, flurothyl, and antipsychotic agents. He described the extrapyramidal effects of the neuroleptics and the delirium associated with L-dopa. His most critical studies were on polypharmacy, reporting the rapidly increasing trend of multiple prescriptions with unpredictable consequences in motor signs, weight gain, delirium, and toxicity.

In an interview published in the CINP volume in 1998, Sid reflected on the size of the hospitalized psychiatric population and the dramatic influence that the establishment of the research center had on clinical care (Merlis, 1998). He recalled the development of rigidity and tremors with neuroleptic drugs, the relief afforded by L-dopa, but also the risk of delirium when its use was not carefully monitored. He described a dramatic experience of the sudden relief of a parkinsonian tremor by the accidental cutting of the anterior choroidal artery, an event that sparked the surgical approach to parkinsonism by undercutting the frontal lobes.

Sid was born in New York City in 1925, graduated from Creighton University with his BA and MD in 1948 and after internship spent 2 years at sea in the US Navy Medical Corps. His postgraduate training was at the New York State Psychiatric Institute and Mount Sinai Hospitals. He was certified in psychiatry in 1955, and served on the VA Behavioral Science Research and the NIMH Clinical Psychopharmacology Committees. As the populations of the Central Islip hospital were decimated by deinstitutionalization, research support flagged and in 1977 Sid turned to private practice, working in an education role at South Oaks Hospital, a large private sanitarium on the south shore of Long Island. He is survived by his wife Annette, three children, Gale, Michael, and Laurence, and three grandchildren.