1970Peer-reviewed · 2 sourcesWell documented
The Controlled Substances Act and the War on Drugs
On the timeline · around 1970 ·
What happened
The 1970 U.S. Controlled Substances Act classified marijuana as Schedule I — the strictest category, defined as having high abuse potential and no accepted medical use, alongside heroin and LSD. Soon after, President Nixon declared a 'War on Drugs.'
Why it matters
Schedule I status made cannabis research nearly impossible and drove decades of arrests, fueling debates over drug policy and mass incarceration that continue today.