1960s

The 1960s mark a decisive reversal in the history of psychedelics: substances investigated as possible tools for therapy and research became, in the public imagination, emblems of social disorder and objects of government restriction. The decade’s familiar story often centers on Timothy Leary, whose public advocacy made him a conspicuous face of the controversy. But the period was larger than his celebrity. The research he came to represent had begun before his work at Harvard, and its collapse emerged from the interaction of street use, medical concern, sensational reporting, and official action.

A decade overshadowed by one public figure

The decade opened onto an already established field of investigation. The Harvard Psilocybin Project began in 1960, after Leary’s first transformative experience with psilocybin in Mexico, but that was not the beginning of serious academic research into psychedelics. Work had been under way during the previous decade in places including Saskatchewan, Vancouver, California, and England. Leary’s later prominence made it easy to mistake the beginning of his own project for the beginning of the field, and his dismissal from Harvard in 1963 for the end of it. Neither impression captures the broader chronology.

Leary nevertheless became central to how the public understood the decade. In 1966, after receiving a thirty-year sentence for attempting to bring a small amount of marijuana across the border at Laredo, Texas, he sought advice from Marshall McLuhan. The meeting took place over lunch at the Plaza Hotel in New York while controversy about LSD and Leary’s advocacy was intensifying. McLuhan advised him to treat his public image as a means of communication and to appear confident and reassuring before cameras. Leary adopted that counsel: in photographs taken afterward, he was repeatedly presented smiling and waving, whether at a courthouse, among young admirers, or in handcuffs as he was being taken to a squad car. The image was memorable, but its very visibility helped make one advocate seem to stand for an entire and much more varied research history.

In the same year, Leary appeared before a United States Senate committee to defend his slogan and his public position. The hearing placed him at the center of a national dispute over whether psychedelics represented personal and cultural change or a threat to established authority. His notoriety did not merely reflect the controversy; it helped shape the way the controversy was narrated. In the book’s account, Leary’s success in influencing the popular story obscures both the researchers who preceded his public moment and the work that continued after his departure from Harvard.

Research and the changing meaning of risk

The decade’s conflict was not simply a contest between advocates and opponents. As nonclinical LSD use spread, emergency rooms and psychiatric wards saw people experiencing paranoia, mania, catatonia, anxiety, and recurring symptoms after use. In 1965, Bellevue Hospital in Manhattan admitted sixty-five people for what it classified as LSD-induced psychoses. Some episodes were genuine psychotic breaks, and LSD could trigger a first episode in young people already at risk for schizophrenia. In other cases, clinicians unfamiliar with psychedelic effects mistook panic reactions for psychosis, a response that could worsen a patient’s distress.

The resulting danger was real, but public accounts often flattened distinctions between different circumstances and outcomes. Reports of acute episodes circulated alongside urban legends and alarming claims. A widely publicized study in Science asserted that LSD could damage chromosomes and potentially cause birth defects; a later refutation, also published in Science, attracted much less attention. The contrast illustrates how evidence could be received selectively once LSD had become established in public discussion as a threat.

Sidney Cohen’s research offers a more measured account of how assessments changed. In an early survey, he gathered information from forty-four psychedelic researchers concerning roughly five thousand subjects and twenty-five thousand occasions of LSD or mescaline use. He found only two credible reports of suicide, along with transient panic reactions, and no evidence of serious prolonged physical side effects in that surveyed population. His conclusion applied to use under qualified professional supervision, not to every setting or manner of use.

By 1962, Cohen was warning about a different and increasingly visible problem: casual use outside clinical settings and use by irresponsible therapists. His subsequent reports described serious complications, psychotic breaks, an attempted suicide, and a boy who experienced visual distortions and anxiety for more than a month after ingesting a sugar cube containing LSD. In 1966, Cohen also reported two accidental deaths associated with LSD. The movement from his comparatively reassuring early findings to these warnings did not amount to a simple reversal. It reflected a growing distinction between controlled therapeutic contexts and an expanding, less controlled circulation of the drug—one that public debate often failed to preserve.

Moral panic and institutional closure

By the middle of the decade, those distinctions were being overwhelmed by a moral panic. Media coverage emphasized catastrophe, and even Life magazine, which had earlier helped introduce readers to psilocybin through R. Gordon Wasson’s enthusiastic account, published a cover story presenting LSD as an uncontrolled threat. Sensational headlines and vivid images helped turn individual incidents into signs of a general crisis. Cohen’s cautionary findings and the genuine risks he documented became part of this climate, while the qualifications surrounding his research were less likely to survive public retelling.

The institutional contraction was swift. In April 1966, Sandoz withdrew LSD-25 from circulation, citing the controversy around the drug and transferring most of its remaining stocks to the United States government. The withdrawal contributed to the closure of many of the seventy research programs then under way. In May, Leary and Cohen testified at Senate hearings, trying to distinguish legitimate research from black-market use. The arguments for preserving medical investigation did not reverse the political direction of events.

In October, about sixty psychedelic researchers across the United States received letters from the FDA ordering them to stop their work. At the International Foundation for Advanced Study in Menlo Park, psychologist James Fadiman received the notice just as four participants in a problem-solving experiment had been given their doses. He delayed acting on the letter until the next day; then that program, along with virtually every other American program still operating, closed. The episode gives the wider shutdown a precise human and institutional scale: an administrative directive arrived in the middle of an experiment, and a research program ended almost at once.

What survived, and what the decade left behind

The shutdown was extensive but not total. The Maryland Psychiatric Research Center at Spring Grove continued psychedelic research until 1976. Researchers there, including Stanislav Grof, Bill Richards, Richard Yensen, and Walter Pahnke, investigated psilocybin and LSD in relation to alcoholism, schizophrenia, and the existential distress of cancer patients. The reasons this program survived when dozens of others were closed remain uncertain. The book records speculation that the work may have retained the interest of influential people in Washington, but does not establish that explanation as fact.

The decade’s legacy therefore cannot be reduced either to a triumph of advocacy or to a story of simple suppression. The first wave of psychedelic science collapsed by the end of 1966, and public fear helped make its institutional restoration difficult. At the same time, the cultural reach of Leary’s advocacy had consequences that became visible decades later. Rick Doblin argued that the generation later entering positions of influence had become familiar with psychedelics through the 1960s, just as practices once treated as strange, including yoga and meditation, had become more accepted. Paul Summergrad, for example, publicly described a psychedelic experience in college as formative for his intellectual development. In this account, Leary’s role is double-edged: his public approach contributed to the conditions in which the first wave was derailed, yet turning a generation toward psychedelics also helped create the cultural conditions for a later research revival.