Cannabis is currently among the most widely used psychoactive substances in the UK. It has been studied clinically, regulated politically, and debated socially for years. Its presence now feels familiar and almost self-evident. Historically, however, this was far from the case. In the post-war period, cannabis played only a minor role in everyday British life, despite long-standing legal controls.

The emergence of a stable cannabis market in the past few decades cannot be explained by the substance’s pharmacologic properties or by individual choices alone. Historian James H. Mills, PhD, director of Humanities Research at the University of Strathclyde, Glasgow, Scotland, offers a unique perspective. He traces the history of cannabis to political decisions, colonial power relations, and social change.

According to Mills, what is available, how a substance is perceived, and what it represents are not inevitable but are shaped by historical processes. These forces continue to influence regulation, prevention strategies, and medical assessments.

Regulatory Paradox

The story begins with a paradox. In Britain, cannabis was subject to legal control long before significant domestic consumption occurred. In the first half of the 20th century, there was no meaningful domestic market for the substance. However, in 1928, cannabis was added to British drug legislation as “Indian hemp.”

This step did not result from national public health concerns but from international obligations. At the 1925 Geneva Opium Convention, cannabis entered the agenda for geopolitical reasons rather than because it posed a clear threat to society. Britain prioritised opium, whereas the US and Egypt pushed for cannabis controls as a bargaining chip. The outcome was early regulation of a substance that was barely consumed in Britain, with no supporting public health data.

Cannabis also lingered on the margins of medical practice. After a phase of 19th-century enthusiasm, it was considered therapeutically obsolete by 1900. A key factor was the failure to identify its active ingredients, in contrast to morphine, which was isolated in the early 19th century. The pharmacology of cannabis remained unclear until the 1960s.

In an age that prized standardised synthetic drugs as markers of medical progress, cannabis appeared unreliable. Early addiction medicine focused on opioids and cocaine, and cannabis simply faded from clinical attention.

Media Narratives

Cannabis then gained surprising visibility in public discourse. In the 1920s and 1930s, tabloid newspapers portrayed it as a “new drug threat,” a plant hidden in English vegetable gardens, or contraband moved through international smuggling rings.

These narratives linked cannabis with migration, sexuality, and social deviance, echoing contemporary drug panics.

However, official reports painted a different picture. In 1940, the Home Office Drugs Branch found no evidence of widespread cannabis consumption among the general population in the UK. Small quantities of hashish occasionally appeared among Asian or African sailors from regions with established traditions of cannabis consumption.

This group was the only population with consistently documented consumption. For most Britons, cannabis remained peripheral until the 1940s, regulated by law but rarely part of everyday life.

Post-War Shift

This situation changed only after the Second World War. Migration from the Caribbean, South and West Africa, and South Asia introduced new cultural practices through workers from former colonies who contributed to post-war reconstruction from the late 1940s onwards.

Music, clothing, and social habits reshaped urban life, and previously invisible consumption patterns became more apparent.

Home Office files captured this shift in ambivalent terms. Migrants were described as indispensable reconstruction labour yet were simultaneously framed as potential sources of a “hashish problem.” The language in these documents carried racist undertones.

These records also documented a two-way cultural exchange. A letter from two 17-year-old British girls asking a contact in London to send “dope cigarettes, reefers, marijuana” marked a turning point. From this point onwards, young people did not just accept new substances; they actively went looking for them.

Urban Integration

By the 1950s, a small but stable cannabis market had emerged for the first time. In cities such as London, Birmingham, Manchester, and Cardiff, young people grew up in increasingly multicultural neighbourhoods. Styles, music, and ways of life were shared, and cannabis became part of everyday urban culture.

Cannabis consumption in these settings was not driven primarily by medical need or acute personal crisis but by a sense of social belonging within particular social milieus.

The 1960s are often portrayed as a decade of breakthrough for cannabis. Mills challenges this view. Cannabis certainly became politically charged during that period as an emblem of counterculture, a rejection of parental norms, and a symbol of post-colonial solidarity.

High-profile arrests, public demonstrations, and parliamentary debates attracted increasing media attention. However, epidemiologically, consumption remained limited. A nationwide survey of police authorities in 1968 found few substantial cases outside London. Cannabis was highly visible but not widespread. It was precisely this discrepancy that gave it symbolic power.

Market Expansion

The situation changed fundamentally only in the 1970s. People born in the 1960s grew up in mixed urban neighbourhoods and increasingly shared similar lifestyles. This shared cultural landscape, visible in music, clothing, and social life, now also encompassed substance consumption. Cannabis was no longer an exotic import but part of local identity.

The new generation and the market developed in parallel. Patterns of consumption followed not only availability or price but also processes of social learning. Data cited by Mills indicate that cannabis consumption was concentrated among individuals aged 16-24 years, with many discontinuing consumption beyond their mid-20s.

In this pattern, cannabis appears less as a chronic addiction and more as a generation-specific cultural phenomenon.

Medical Re-Emergence

At the same time, cannabis re-entered medical debate in the 1990s. This renewed interest was driven by the heroin crisis of the 1980s, growing distrust of the pharmaceutical industry after the thalidomide scandal, and the AIDS crisis, during which many existing therapies were perceived as inadequate.

In 1992, the Alliance for Cannabis Therapeutics was established, and clinical studies were initiated within its network. With the development of GW Pharmaceuticals the rights to the commercialisation of Sativex, cannabis regained a place in therapeutic discussions.

Mills emphasised that this renaissance was not a linear outcome of advancing pharmacologic knowledge. It resulted from the interplay between social demand, political frameworks, and industrial innovation strategies.

For evidence-based medicine, this leads to an uncomfortable insight: Therapeutic debates about cannabis cannot be separated from their social context.

Mills argued that the British cannabis market did not arise simply from individual preferences but was formed through specific historical processes. Regulation, prevention, and provision will remain limited in their impact if they overlook historical legacies, entrenched cultural influences, generational patterns, and migration contexts.

This story was translated from Univadis Germany, part of the Medscape Professional Network.