The criminologist and psychiatrist Donald West, who has died aged 95, made his name with his book Homosexuality, first published in 1955. The time was right, West wrote then, to deal with the “problem” of homosexuality in a dispassionate and popular manner.

Very little had been published previously on the subject for a wide readership. It is difficult now to imagine the courage it took West to publish the work at that time in the UK. The 1950s were still in the grip of a witch-hunt against homosexuality – and male homosexuality was illegal.

The Wolfenden committee, set up to reconsider the law, was still deliberating, and it was to be another two years before its recommendations for modest reform were published. In that context West took a major personal risk, and the book was to play an important part in changing the climate of opinion towards homosexuality in Britain.

It was the first serious non-fiction book on the subject that I encountered, in the mid-60s, and, in its sober Pelican editions, it was a work that was to appear over and over again on the bookshelves of my friends. It was very influential. What it was not was a call to arms.

In a fashion that was to become characteristic of West’s writing, it was a sober, cautious, thorough presentation of the evidence about homosexuality in history, society and psychology, with some case studies from “self-confessed” homosexuals to leaven the dough. It concluded in a conventionally downbeat way by suggesting that no doctor should advise a young person to be content with his sexual orientation without a “grave warning” – “about the frustration and tragedy that so often attend this mode of life”.

It was this distancing and apologetic tone that many of my generation later objected to, and West’s own extreme discretion about his own homosexuality did nothing to enamour him to the gay liberationists of the 70s. He had many difficult encounters with activists who heckled his lectures. Caution was ingrained in his bones.

Yet West’s intention, as he made clear in his late memoir, Gay Life, Straight Work (2012), was to help the cause of greater understanding and legal reform, and he risked his career to do so. He went about as far as he felt he could for that time. As he put it in his memoir, “For a young, unmarried professional to have stuck his neck out so recklessly seems, in retrospect, quite crazy … I was protected by the hypocritical medical label.”

By this he meant that the scientific and medical claims of the book gave it a necessary cover, just as his own professional credentials allowed him to write it as if an outsider. Even so it was seized by Australian customs and appeared only with a bowdlerised title, The Other Man, in the US.

Donald was born in Liverpool, in a traditional red-brick workers’ house near the docks, the only child of John, a catering manager with Cunard, and Jessie; is parents were of working-class origins with high aspirations. He was a sickly child, cosseted by his religious mother, who died when Donald was 11. His father remarried.

Academic success changed Donald’s life. He won a scholarship to the fee paying Merchant Taylors’ school in Liverpool, and went on to study medicine at Liverpool University. There he began a lifelong interest in the paranormal, finding in it an alternative to the religious enthusiasms of his parents.

He qualified as a doctor in 1947 and as his first job became a research officer with the Society for Psychical Research in London. His first book, Psychical Research Today, published in 1954, was on the paranormal. He was sceptical of the claims of many spiritualist enthusiasts, but was convinced that extrasensory perception had a genuine psychological basis, deserving scientific laboratory research and statistical analysis. He remained committed to studying the paranormal throughout his career, and served several times as the president of the SPR.

After training as a psychiatrist at the Maudsley hospital in south London, and at Liverpool University, he joined the newly established Institute of Criminology in Cambridge in 1960 as assistant director of research, and spent the rest of his career there, as lecturer, reader then professor of clinical criminology, and was director of the institute from 1981 to his formal retirement in 1984.

There he pursued the third strand of his research interests, the psychological aspects of crime, focusing on what was known at the time as delinquency. He published a study on the relationship between murder and suicide in 1966, and initiated a major longitudinal study of youthful delinquency and persistent offenders. His last major study, conducted after his retirement, was of male prostitution, co-authored with Buz de Villiers, and published in 1992.

West was appointed to the Parole Board on its foundation in 1968, and served as a mental health commissioner (1992-97).

He continued to write on homosexuality, both in new editions of his original book and in a comparative study, Sociolegal Control of Homosexuality (1997), with Richard Green, of controls on homosexuality across countries.

His memoir, quite different from his academic style, was written with the encouragement of a gay writers’ workshop and for many years he attended social meetings of Opening Doors London, the leading organisation for older LGBT+ people. West appeared an austere and in his own words a not particularly clubbable person, but he had a dry wit and a wide and eclectic network of friends.

He was in a relationship with the art historian Pietro Raffo for more than 45 years until Raffo’s death in 2000.

In 2006, he entered into a civil partnership with Vincenzo, who survives him.

• Donald James West, writer and criminologist, born 9 June 1924; died 31 January 2020