In a recent episode of Tucker Carlson’s podcast, renowned psychiatrist and brain imaging specialist Dr Daniel Amen shared startling insights about cannabis use and its effects on brain function. Drawing from decades of research and over 300,000 brain scans, Dr Amen’s findings challenge widespread perceptions about the safety of marijuana.

The Physical Impact of Cannabis on the Brain

Dr Amen’s research on cannabis effects on the brain reveals concerning patterns. In his study of 1,000 marijuana users compared to a healthy control group, every area of the brain showed lower blood flow and activity. Using SPECT (Single Photon Emission Computed Tomography) imaging, which examines both blood flow and mitochondrial function, the research demonstrates measurable changes in brain physiology.

The mitochondria, often called the powerhouses of cells, show significantly reduced activity in cannabis users. As Dr Amen explains, 49% of the tracer used in SPECT scans is taken up by mitochondria in the brain, making decreased activity particularly concerning. Lower mitochondrial function correlates with tiredness, reduced motivation, depression, and increased anxiety.

Cannabis and Mental Health: The Connection to Psychosis

Perhaps most alarming is the emerging research connecting heavy marijuana use to psychosis. Dr Amen references studies showing that individuals with certain genetic variations face dramatically elevated risks. One particular gene abnormality increases the risk of psychosis by sevenfold (700%) in heavy cannabis users.

Even for those without specific genetic vulnerabilities, the risk of psychosis increases by two to four times, particularly when use begins at a young age. Teenagers who use cannabis show higher incidences of anxiety, depression, suicide, and psychosis in their twenties.

The mechanism behind this connection involves dopamine disruption. Whilst cannabis initially activates dopamine receptors, creating feelings of reward, in vulnerable individuals it can severely disrupt normal dopamine function. When dopamine levels become too elevated, some people begin losing touch with reality, experiencing delusions and hallucinations characteristic of psychotic episodes.

The Developing Brain and Long-Term Cannabis Effects

Young people face particular vulnerability to cannabis effects on brain development. Dr Amen emphasises that using substances during crucial developmental periods fundamentally alters how the brain matures. Current statistics paint a concerning picture: according to CDC data referenced in the discussion, 57% of teenage girls report persistent sadness, whilst 32% have contemplated suicide.

The cerebellum, which comprises 10% of brain volume but contains 50% of the brain’s neurones, shows particular sensitivity to both alcohol and marijuana. This region, once thought to control only physical coordination, is now understood to govern thought coordination and information processing speed. Cannabis slows cerebellar function, resulting in slower thinking and reduced coordination.

Cannabis Use and Cognitive Decline

Research indicates that marijuana increases the risk of dementia. In Canada, cannabis use amongst people over 50 increased from 5% to 21% over 15 years. This trend particularly concerns researchers given that 50% of people aged 85 and older will be diagnosed with some form of dementia.

Studies on younger users reveal additional worries. Research on 1,000 young marijuana users found decreased blood flow and activity in brain areas involved in learning and memory. For individuals under 50 who use cannabis, one study showed a 600% increased risk of heart attack, suggesting broad impacts on vascular health that extend beyond the brain.

Cannabis Effects on Brain Structure and Function

Brain imaging reveals that chronic cannabis use is associated with reduced brain volume. Research from the University of Pittsburgh found that overweight individuals had 4% less brain volume and brains that appeared eight years older than their chronological age. Obese individuals showed 8% less volume and brains appearing 16 years older.

When combined with other risk factors such as obesity, cannabis use compounds the negative effects on brain health. The combination of substances, poor nutrition, and sedentary behaviour creates what Dr Amen describes as a “toxic brain” – one that appears older and functions less efficiently than it should.

The Cannabis Industry and Public Health

Dr Amen draws parallels between the cannabis industry and previous pharmaceutical controversies. The marijuana industry spends approximately $3 billion annually on marketing, promoting the message that cannabis is harmless or even beneficial. This marketing push has successfully reduced public perception of marijuana’s dangers, which historically correlates with increased use.

When asked about pushback from the cannabis industry, Dr Amen confirms he faces regular attacks on social media, with critics calling him a “charlatan” and suggesting his medical licence should be revoked. This resistance to discussing research findings mirrors patterns seen with other addictive substances when financial interests are threatened.

Cannabis and Relationships

The effects of cannabis extend beyond individual health to interpersonal relationships. Dr Amen recounts working with NBA player Julius Randall, whose marijuana use was damaging his marriage. Randall’s wife reported he wasn’t present – a common complaint about cannabis users. After stopping use, Randall recognised that the substance had diminished his engagement with what truly mattered: his family and personal values.

This pattern reflects broader research on cannabis effects on brain function related to motivation and emotional connection. The substance doesn’t simply alter mood in the moment; it can fundamentally change how individuals prioritise and engage with important relationships and responsibilities.

Understanding Addiction Potential

Contrary to popular belief that cannabis isn’t addictive, research shows clear addiction potential. For young people using marijuana, there’s a 17% chance of developing dependence. For older adults, the risk drops to 9%, though this still represents significant addiction potential. These rates are comparable to alcohol, which has a 15% addiction rate.

The challenge with using cannabis for pain management, as Dr Amen explains, is that it suppresses pain without addressing root causes. When use stops, pain returns, often leading to continued use and potential dependence. This creates a cycle where the substance becomes necessary for function rather than truly healing the underlying condition.

Medical Uses: Separating Fact from Fiction

Whilst Dr Amen acknowledges limited legitimate medical applications for cannabis – specifically for glaucoma and appetite stimulation in conditions like cancer – he stresses these represent narrow use cases. Pharmaceutical preparations already exist that isolate beneficial compounds without the psychoactive effects and health risks of whole-plant cannabis.

The idea that cannabis serves as effective medicine for a wide range of conditions doesn’t align with neurological research. For anxiety, marijuana often makes symptoms worse over time. For depression, it may provide temporary relief whilst underlying brain inflammation continues.

Brain Health: A Path Forward

Rather than focusing solely on substance avoidance, Dr Amen advocates for teaching people to “love their brains” – to understand that every choice either supports or undermines brain function. This involves asking a simple question: “Is what I’m doing right now good for my brain or bad for it?”

His BRIGHT MINDS protocol addresses 11 major risk factors for brain health:

• Blood flow
• Retirement and ageing
• Inflammation
• Genetics
• Head trauma
• Toxins
• Mental health
• Immunity and infections
• Neurohormones
• Diabesity (diabetes and obesity)
• Sleep

Each factor plays a role in long-term brain health and dementia prevention. Addressing these through lifestyle changes, proper nutrition, exercise, and avoiding harmful substances provides a comprehensive approach to maintaining cognitive function throughout life.

The Importance of Brain Imaging

Dr Amen’s work demonstrates that brain scans can reveal toxic effects from substances, environmental factors, or infections. In his practice, he frequently encounters teenagers referred for ADHD evaluation whose brain scans show toxicity patterns inconsistent with ADHD alone. These scans often reveal drug use, mould exposure, or infections like Lyme disease affecting brain function.

The ability to visualise brain health serves as a powerful motivator for change. Patients seeing their own “toxic brain” often recognise the need to address substance use or environmental factors they’d previously denied or minimised.

Protecting Young People

Young people face particular vulnerability due to developing brains and increasing social pressure. Dr Amen notes that teenage cannabis use correlates with higher rates of mental health problems in the twenties. The perception that marijuana is innocuous has led to widespread use amongst adolescents at a critical time for brain development.

Education focused on brain health rather than simply warning against drugs may prove more effective. When young people understand how their brains work and what supports optimal function, they can make informed decisions based on their own goals and values rather than simply rebelling against warnings.

Cannabis Potency: A Growing Concern

Modern cannabis is dramatically more potent than marijuana available in previous decades. Higher THC concentrations mean greater impact on brain function and increased risk of adverse effects including psychosis. This increased potency, combined with decreased perception of harm, creates a particularly dangerous combination for public health.

What Does Marijuana Do to the Brain?

The question of what marijuana actually does to brain tissue can be answered through neuroimaging. Dr Amen describes seeing “toxic brains” in teenagers – scans that show patterns of damage inconsistent with normal adolescent development. When a 16-year-old’s brain appears toxic on imaging, the investigative work begins: is it drug use, mould exposure, or infection?

In cases of marijuana use, the scans often serve as what Dr Amen calls “a little bit like a lie detector.” When confronted with clear evidence of brain toxicity and no other explanation, young people often admit to substance use they’d previously denied. The visual evidence becomes undeniable.

The cerebellum, that “Rodney Dangerfield part of the brain” that gets no respect, shows particular vulnerability. This structure, connected throughout the rest of the brain, governs both physical and thought coordination. Marijuana slows cerebellar function, which explains the classic “stoner” profile: slow speech, droopy eyes, reduced activity, and poor coordination.

The Industry Behind the Message

When asked how the marijuana industry differs from pharmaceutical companies like Purdue Pharma that misled the public about opioids, Dr Amen’s assessment is blunt: it’s “a weapon of mass destruction.” The industry spends £3 billion annually on marketing, promoting cannabis as harmless or beneficial.

This characterisation as a weapon isn’t merely rhetoric. Dr Amen later explores what he calls the “evil ruler strategy” – if one wanted to create a docile, mentally ill population, what would one do? The answer includes promoting substances that lower brain function, reduce testosterone, increase passivity, and diminish critical thinking. In his book The End of Mental Illness, he imagined this exact scenario: an evil ruler seeking to create mental illness in a population would promote the very substances and behaviours currently being normalised in society.

The comparison extends to alcohol as well. Dr Amen conducted what he describes as a “prize fight” between marijuana and alcohol that “went 12 rounds.” His conclusion? Alcohol causes tremendous devastation, perhaps even more than marijuana. Yet society has been sold the lie that alcohol is a health food – that a glass or two of wine each evening benefits heart health.

The American Cancer Society countered this narrative four years ago, stating that any alcohol consumption increases the risk of eight different cancers. The brain science is equally clear: alcohol is bad for your brain. Yet the societal lie persists, promoted by industries that profit from consumption.

California, the largest marijuana-growing region in the country (possibly the world), produces the highest-potency cannabis. The economic incentives are substantial, which Dr Amen believes explains why public health authorities remain silent about the dangers. Money and influence drive policy, even when research clearly demonstrates harm.

He draws parallels to historical patterns: the congressman from Kentucky who wouldn’t acknowledge smoking caused cancer due to tobacco industry pressure. The mechanism is identical – financial interests override public health concerns.

The Question of Legalisation

Dr Amen suggests that whilst cannabis legalisation has generated tax revenue for states like California, the public health costs haven’t been adequately addressed. When asked if legalisation could be rolled back in California, his response is telling: “Not with the current administration.” The power structures and financial interests are simply too entrenched.

Rather than focusing on prohibition, he advocates for honest public education about cannabis effects on brain health and mental wellbeing. The comparison to alcohol prohibition is instructive: rather than banning substances, societies might better serve their populations through comprehensive education about brain health and the true impacts of psychoactive substances.

A National Brain Health Revolution

Dr Amen’s ultimate goal involves creating widespread awareness of brain health principles. If individuals consistently ask whether their choices support or harm their brain function, many problems associated with substance use might naturally decrease.

This approach shifts from prohibition and punishment to education and empowerment. By helping people understand what they want in life – strong relationships, career success, emotional wellbeing – and how brain health enables these goals, the choice to avoid harmful substances becomes self-motivated rather than externally imposed.

This article reviews and discusses research findings presented in Tucker Carlson’s interview with Dr Daniel Amen, examining current neuroscience research on substance use and brain health.

Source: YouTube