Jules Angst died in his hundredth year. When I learnt of his death, I was dumbfounded, as I had come to come to take his longevity for granted. I got to know him soon after taking up the chair of Clinical and Social Psychiatry at the University of Zurich psychiatric hospital (‘the Burghölzli’) in 1996, when he asked me whether I wanted to take over the – by then legendary – Zurich psychiatric epidemiology cohort study. So began 30 years of friendship and scientific collaboration. One of the most influential psychiatrists of our times, Jules Angst helped change the landscape of mental health research for the benefit of untold numbers of patients, and his legacy survives in the work of many scientists and clinicians.

Jules, who was born in 1926 and died in May this year, grew up in Zurich, Switzerland. His father was a technical draftsman with the railways, and his mother managed a baker’s shop. He was not destined by birth for academe. But by the age of ten he knew that he wanted to be a doctor. What he had in abundance was energy, brain power and an appetite for reading and hard work. From his father, who was an amateur entomologist, he learned the importance of observation and classification. University study was possible because he was an only child. Student jobs at the post office, as a lifeguard and in his uncle’s carpentry shop paid for a typewriter and his training analysis with the Jungian Kurt Binswanger.

After medical studies in Zurich (1946–52) and military service, he started as a junior doctor at the Burghölzli. The hospital was headed at the time by Manfred Bleuler and it was associated historically with many famous names, including Eugen Bleuler and Carl Gustav Jung. Jules’ immediate task was to provide analytic psychotherapy for patients with schizophrenia under the supervision of Gaetano Benedetti. Jules came to question the general enthusiasm for this approach; he found it ineffective and, like the child in Hans Christian Andersen’s tale, he declared that the emperor had no clothes. Although disappointed by the psychoanalytic treatment of patients with schizophrenia, psychotherapy was always one of the tools of his trade.

In the early 1960s junior doctors had to live on hospital premises, but as married doctors were exempt from this rule, Jules and his wife, Lisbeth Rickenmann, took a flat directly opposite his workplace. Their children, Katrin and Felix, grew up and played in the Burghölzli’s grounds, alongside the hospital patients. Both children became doctors, and Katrin later worked as a consultant in the same hospital. When Jules moved there in 1962, he couldn’t have guessed that this flat would be his home for over half a century. His main regret on moving out was that his office was now more than 5 minutes’ walk away.

Repeatedly standing at a professional crossroads, Jules was remarkably clear-sighted not only about psychiatry but also about his career, and he side-stepped flattering offers that distracted from his purpose. Only once was he tempted to accept a post abroad, at Columbia University, New York. His chief, Manfred Bleuler, was discouraging and couldn’t guarantee him a job to return to, a serious consideration at that time. So, Jules stayed in Zurich, where he would live for the rest of his life. From there he cultivated friendships and scientific exchange with his colleagues the world over and travelled widely.

Another turning point was his early decision to focus on affective disorders; he explained with typical self-deprecation that many bright minds were already investigating schizophrenia. More probably he considered that the relatively unexplored field of mood disorders offered great scope for original research and creativity.

Following the data and thinking outside the box were key characteristics of his post-doctoral monograph.Footnote ^a With exemplary methodology he established, among other things, the heterogeneity of ‘endogenous’ depression, distinguishing between unipolar depression and bipolar disorder. These were landmark findings, which despite initial resistance from psychiatry’s great and good were confirmed and had a lasting impact on the diagnosis and treatment of mood disorders.

In 1969, Jules was appointed professor of clinical psychiatry at the University of Zurich. This was another turning point where his clarity of purpose was rewarded, as, on Manfred Bleuler’s retirement, he declined the invitation to take over his mentor’s multiple roles as director of the Burghölzli. He was offered instead the new post of research director, which he occupied until his own official retirement in 1994. At no time did he stop treating patients.

The research department was generously funded and for decades a leader in Europe for the quality and volume of its output. It became a biotope for diverse fields of psychiatry: epidemiology, psychopathology, psychology, sociology, clinical neurophysiology, mathematical models, statistics and genetics and their related research projects. Pioneering work in clinical psychopharmacology was carried out and new standards were set. International collaborative research established that lithium was an effective prophylactic agent in the treatment of recurrent affective disorders.Footnote ^b All research was rigorously empirical.

Jules Angst is probably best known for the Zurich cohort study, which began in 1978. Building on his earlier studies of patients and army recruits, he designed an epidemiological study to assess psychiatric conditions in the general population of the canton of Zurich. The study focused on mood disorders but encompassed far more than anxiety and depression. It covered a wide range of somatic symptoms – menstrual, gastrointestinal, cardiovascular, respiratory – sleep disturbance, psychosomatic conditions, headache, alcohol, tobacco and drug consumption, childhood experience and much more.

Two aspects distinguished the Zurich study. First, it examined psychiatric disorders in the general population, not in patients. Second, psychiatric conditions were not fitted into predefined diagnostic categories but described in terms of a spectrum or continuum of symptoms from normal to pathological. The cohort was followed longitudinally for 30 years, from the ages of 20 to 50. The study yielded hundreds of articles, co-authored with national and international scientists. We last published together – with Jules as first author – in 2020. Real retirement for Jules began at age 95.

Jules Angst received numerous prestigious honours in recognition of his work. In addition to two honorary doctorates, Heidelberg (Germany) 1988 and Craiova (Romania) 2014, they included the Honorary Fellowship of the Royal College of Psychiatrists (1986), the Emil Kraepelin Gold Medal (1992) and latterly the Jean Delay Prize of the WPA (2017) and the Wilhelm Griesinger Medal of the German Society for Psychiatry (2018). Many of his awards are named after the giants of psychiatry, among whom he belongs.

Jules is survived by Katrin and Felix, the children from his marriage to Lisbeth Rickenmann (died 2004), by Xenia his granddaughter (also a doctor) and by his wife, Elizabeth Kyrke.