Science does not need to be hermetic to be true
Num momento em que décadas de progresso nas políticas de drogas enfrentam uma maré conservadora global, o neurocientista brasileiro Sidarta Ribeiro publica em Portugal uma obra que convoca a ciência e a linguagem acessível para defender a regulação racional da cannabis. Portugal, que em 2001 inaugurou um modelo legislativo admirado no mundo inteiro, serve de prova viva de que é possível tratar a questão com responsabilidade — mas também de alerta sobre o que pode ser perdido. Ribeiro acredita que o arco longo da história aponta para a liberdade e a evidência, mesmo que as forças da regressão continuem a fazer pressão.
- Uma vaga reacionária global ameaça desfazer décadas de avanços na descriminalização das drogas, colocando em risco modelos como o português de 2001.
- A desinformação e o estigma persistem porque o conhecimento científico permanece fechado em linguagem académica, inacessível à maioria dos cidadãos.
- Adolescentes são o grupo de maior risco: o cérebro em desenvolvimento é vulnerável aos efeitos da cannabis, com consequências documentadas na memória, motivação e saúde mental.
- Ribeiro propõe um ecossistema regulatório diversificado — do cultivo doméstico às cooperativas — que impeça monopólios e priorize as comunidades mais prejudicadas pela proibição.
- Uruguai e Canadá surgem como referências positivas, enquanto os Estados Unidos representam o polo oposto, marcado por preconceito enraizado e incompreensão científica.
- O livro chega como um instrumento de cidadania: a literacia científica, defende Ribeiro, não é um privilégio — é uma condição essencial para a democracia no século XXI.
Sidarta Ribeiro, neurocientista brasileiro, acaba de lançar em Portugal "As Flores do Bem", editado pela Quetzal — um livro que aborda a cannabis com rigor científico e linguagem clara, numa altura em que os avanços das políticas progressistas de drogas enfrentam o que o autor designa de "vaga reacionária". Para Ribeiro, as forças conservadoras que hoje pressionam em sentido contrário à descriminalização não são apenas um fenómeno político local: são uma ameaça global ao trabalho cuidadoso de décadas. Ainda assim, mantém-se convicto de que a racionalidade prevalecerá.
Portugal ocupa um lugar central no argumento do livro. A legislação aprovada em 2001 continua a ser observada como modelo em todo o mundo, e Ribeiro fala com admiração pelo que o país construiu — e com preocupação pelo que pode perder. A tendência para a descriminalização avança, diz ele, mas a regressão espreita. A resposta que propõe passa pela literacia científica: a ciência não precisa de ser hermética para ser verdadeira, e o conhecimento que não chega aos cidadãos é conhecimento desperdiçado.
O livro não evita os riscos. Um capítulo inteiro é dedicado ao excesso, e a posição de Ribeiro é clara: a cannabis pode beneficiar adultos e idosos, mas representa um perigo real para adolescentes, cujo cérebro ainda está em formação. O uso precoce e intensivo associa-se a síndrome amotivacional, prejuízos no desempenho escolar e aumento do risco de psicose em indivíduos vulneráveis. Mesmo nos adultos, o uso crónico não é isento de riscos, embora os efeitos tendam a ser mais benignos.
A regulação que Ribeiro defende é exigente e multidimensional: controlo de qualidade, educação para a redução de danos, diversidade no ecossistema de produção e distribuição — sem monopólios, sem publicidade comercial. E uma dimensão de reparação social: as comunidades mais afetadas pela proibição devem ter acesso prioritário aos mercados legais, à semelhança do modelo de Nova Iorque. As escolas, por sua vez, devem ensinar os efeitos e riscos da cannabis de forma honesta e diferenciada. É para este momento — em que a exploração informada da questão importa mais do que nunca — que o livro foi escrito.
Sidarta Ribeiro, a Brazilian neuroscientist, has just published a book in Portugal that treats cannabis with the rigor of science and the clarity of plain language. The book, "As Flores do Bem" (The Flowers of Good), released by Quetzal, arrives at a moment when the gains of decades of progressive drug policy face what Ribeiro calls a "reactionary wave"—a global conservative backlash that threatens to undo the careful work of decriminalization and rational regulation.
Portugal itself stands as proof that another approach is possible. More than twenty-five years ago, the country quietly debated cannabis policy in ways that culminated, in 2001, in legislation that the world still watches as a model. That achievement now feels fragile. Ribeiro speaks with both admiration for what Portugal has done and alarm at what could be lost. "The tendency toward decriminalization spreads," he says, "but the reactionary wave, fed by dark political and social forces, continues to threaten us with regression." Yet he remains convinced that rationality will ultimately prevail—that the global arc, despite the noise of opposition, bends toward freedom, responsibility, and evidence-based policy.
The book itself refuses the trap of false balance. Ribeiro writes with scientific precision but without jargon, believing that knowledge locked in academic language is knowledge wasted. "Science does not need to be hermetic to be true," he explains. "Clear writing, without losing seriousness, helps popularize science and make it accessible without sacrificing rigor." This matters especially for cannabis, where misinformation and stigma have clouded public understanding for generations. When the academy speaks only to itself, he argues, we lose the chance to turn knowledge into real change. Scientific literacy, he suggests, is not a luxury—it is a condition of citizenship in the twenty-first century.
Ribeiro does not shy from risk. The book includes a chapter titled "Loving the Flowers Too Much," which opens with a simple truth: "Everything in excess is complicated—and cannabis is no exception." Adolescents are the primary at-risk group. The teenage brain is still developing, and cannabis can interfere with that process, particularly in areas governing memory, learning, and emotional control. Early and heavy use is linked to what researchers call amotivational syndrome—apathy, lost ambition, passivity, social withdrawal, difficulty concentrating—with measurable harm to school performance and mental health. The risk of psychosis in vulnerable individuals rises. The exception is clinical indication, such as epilepsy treatment. Otherwise, his position is categorical: the plant may benefit adults and older people, but not children and teenagers.
Even among adults, chronic use carries risks. Cannabis can alter brain regions tied to memory and decision-making, the hippocampus and prefrontal cortex. Yet Ribeiro notes that in adults and the elderly, the effects tend to be neuroprotective and generally benign, though dependence risk remains real. The path forward, he argues, requires multiple elements working together: destigmatization, effective regulation, and quality scientific education. The cannabis industry must be regulated to ensure low cost, quality, and safety without falling into aggressive marketing and irresponsible promotion. No psychoactive drug should be advertised commercially.
The production and distribution ecosystem must be diverse and balanced—home cultivation, patient associations, cooperatives, user clubs, and both public and private companies, especially smaller ones, to prevent monopolies. The social dimension cannot be forgotten. Communities most harmed by drug prohibition deserve priority access to legal cannabis markets, following models like New York's reparations approach, where incarcerated Black and Indigenous people gain priority for sales licenses. Schools must teach cannabis use honestly, explaining effects and risks for different groups, teaching safe and conscious consumption.
Ribeiro points to Uruguay and Canada as successes, their models built on harm-reduction education, quality control, and effective regulation. The United States occupies the opposite end of the spectrum. Prejudice remains deeply rooted, he notes, with origins not only in the racist history of criminalization but in fundamental misunderstanding of how cannabis actually affects the brain and body. In Portugal, where cannabis is already treated more rationally than in many countries, Ribeiro hopes his book will find readers ready to explore the plant's many dimensions—scientific, historical, social, and personal. He has written it for a moment when that exploration matters more than ever.
Notable Quotes
The tendency toward decriminalization spreads, but the reactionary wave, fed by dark political and social forces, continues to threaten us with regression.— Sidarta Ribeiro
The plant may benefit adults and older people, but not children and teenagers.— Sidarta Ribeiro
The Hearth Conversation Another angle on the story
You describe a "reactionary wave" threatening cannabis policy. What does that actually look like on the ground?
It's political movements gaining power in various countries, pushing for recriminalization or stricter enforcement, often using fear and misinformation. It's the opposite of what Portugal did quietly and successfully in 2001.
Why does Ribeiro think Portugal's model works when so many other countries have failed?
Because Portugal treated it as a public health issue, not a criminal one. They combined decriminalization with education and harm reduction. No moral panic, no prison sentences for possession. Just rational policy.
But he's clear that cannabis isn't harmless, especially for young people. How does that fit with decriminalization?
It doesn't contradict it. Decriminalization means removing criminal penalties, not endorsing use. You can be honest about risks—especially for developing brains—while still treating users as people who need help, not punishment.
He mentions his own spiritual experience with cannabis in the 1990s. Why include that in a science book?
Because it's honest. Science doesn't have to pretend researchers are machines. And cannabis does facilitate introspection and self-knowledge for some people. That's a real effect worth studying, not hiding.
What does he mean by "ritualized" use becoming a trend?
Using cannabis as part of spiritual or cultural practice, with intention and respect, rather than casual consumption. It's already happening in some communities. He thinks it will expand, but only if we move past the stigma and prohibition that have warped how we understand the plant.
The book calls for diverse production—home growing, cooperatives, small businesses. Why not just let the market handle it?
Because markets concentrate power. Without intentional diversity, you get oligopolies controlled by big corporations. And you lose the chance to repair harm—to give licenses and resources to the communities most damaged by the drug war.