For decades marijuana was seen mainly as a harmless recreational drug. Today, however, the conversation is shifting. The legal cannabis industry is now worth more than $38 billion, and high-potency products have become widely available. Yet alongside the booming business is a troubling rise in cannabis-induced mental health problems, especially among young people.
Dr. Kristen Gilleland, a neuroscientist and assistant professor at Vanderbilt University, knows these dangers firsthand. Despite her PhD in organic chemistry and years of teaching neurochemistry, she could not prevent the tragedy that struck her own family. Her son Anders began using marijuana at 14, believing it eased his anxiety. Instead, he developed cannabis-induced psychosis hearing voices, staying awake for days, and spiraling into severe mental illness. Eventually he turned to harder substances, dying from an accidental overdose at age 22.
Cannabis-induced psychosis is more than just feeling paranoid after smoking. It involves a complete loss of contact with reality hallucinations, delusions, and extreme paranoia. Hospitals around the country report rising cases of cannabis-induced psychiatric emergencies, often in teenagers or young adults. High-THC vape pens and concentrates, sometimes exceeding 50–90% THC, are far stronger than the 2–3% THC marijuana of previous generations. These ultra-potent products dramatically increase the risk of cannabis-induced mental disorders.
Research now suggests that cannabis-induced psychosis can act as a trigger for latent conditions such as schizophrenia or bipolar disorder, particularly in individuals with a genetic predisposition. One Danish study found that one in five young men who developed schizophrenia might have avoided it if they had never developed cannabis use disorder. Dr. Gilleland believes her son’s cannabis-induced psychosis was the first step in a cascade of addiction and mental health struggles.
Parents, educators, and policymakers must take this issue seriously. Legal status does not equal safety, especially for developing brains. The endocannabinoid system in adolescents governs cognition, motivation, reward, and emotional regulation. THC disrupts that delicate system, making cannabis-induced changes to brain development more likely and more harmful.
Dr. Gilleland now dedicates her life to prevention. Through speaking engagements, research, and her documentary Speaking Through Me, she hopes to warn other families about the risks of cannabis-induced psychosis and addiction. Her message is clear: high-potency marijuana products are not benign. Understanding the science of cannabis-induced mental health effects could spare countless young people and families from heartbreak.