Is Today's Cannabis a Different Drug? Potency, CBD, and Your Brain
By Dr. Anindo Mitra, Consultant Psychiatrist (MBBS, MD Psychiatry, JIPMER). Athena Behavioural Health, Gurugram.
TL;DR
• The cannabis available today is far stronger than a generation ago. Average THC in seized samples roughly quadrupled between 1995 and 2022, and concentrates can exceed 60 to 90 percent THC.
• Modern strains are bred high in THC and low in CBD, the compound that may partly soften THC's effects.
• Higher potency and daily use track with higher odds of psychosis. Among people who have a single cannabis-induced psychotic episode, close to half later develop schizophrenia or bipolar disorder.
• Most people who use cannabis will not develop psychosis. The risk concentrates in a specific group: family history of serious mental illness, early and frequent use, and high-potency products.
• Cannabis carries lower risk than alcohol or tobacco on several measures, but it is not harmless. The only zero-risk option is not using.
Cannabis has a long cultural history in India. Bhang features in the worship of Shiva and in the thandai served at Holi and Maha Shivaratri, and phrases like "I tried it in college, I turned out fine" are common across urban India. The reassurance sounds reasonable. The problem is that the drug being compared has quietly changed. What circulated decades ago and what a young person vapes today are, pharmacologically, close to two different substances. That difference matters most for one organ: the brain.
Is today's cannabis actually stronger?
Yes, substantially. In cannabis seized by law enforcement, average THC content rose roughly fourfold between 1995 and 2022, from about 4 percent to 16 percent , and dispensary flower and concentrates can reach 40 percent and beyond. The plant material of the 1970s sat in the low single digits.
Two shifts drive this. The first is decades of selective breeding for potency. The second is the rise of concentrates, waxes, shatter, vape oils and dabs, which can carry 60 to 90 percent THC. In Indian cities the product mix is changing too, with vapes and higher-grade charas appearing alongside traditional ganja. The headline is not a single percentage. It is that the dose of THC delivered in one session has climbed sharply, and the body and brain respond to dose.
The CBD story: a safety catch, quietly removed
As THC has climbed, cannabidiol has fallen. In two decades of US potency data, the THC-to-CBD ratio widened from roughly 14 to 1 in 1995 to around 80 to 1 by 2014 . This matters because CBD may buffer some of THC's psychoactive and anxiety-provoking effects, though that evidence is still promising rather than settled.
Think of CBD as a partial counterweight. Breeding it out of high-THC strains may remove some of that counterweight, not just change what is printed on the label. A modern high-THC, low-CBD product is a more concentrated dose of the very compound linked to acute psychological effects, with less of the compound that might have tempered it.
How cannabis can tip the brain toward psychosis
THC acts on the brain's cannabinoid (CB1) receptors, which sit on neurons that regulate glutamate and, further downstream, dopamine. Both systems are central to psychosis. Sustained THC exposure appears to disrupt glutamate signalling through CB1 activation, with knock-on effects on dopamine regulation. Excess dopamine activity in specific circuits is closely tied to the positive symptoms of psychosis, such as delusions and hallucinations.
A simpler way to picture it: the brain runs on a finely balanced signalling system, and repeated high-dose THC can nudge that balance off. In vulnerable individuals, the system loses some of its tuning, and thoughts and perceptions can start to distort.
Why adolescence raises the stakes
The developing brain is more vulnerable. Through adolescence, the glutamate and dopamine systems are still being pruned and refined, and cannabis exposure during this window is associated with greater psychosis risk than use beginning in adulthood (https://www.nature.com/articles/s41398-021-01295-w). This is a central reason clinicians treat early, heavy use as a distinct concern rather than a milder version of adult use.
What the psychosis numbers really say
Precision matters here, because this statistic is often mangled online. In a large Danish registry study, among people who had one cannabis-induced psychotic episode, about 47 percent later developed schizophrenia or bipolar disorder . This is not 47 percent of cannabis users. It describes people who have already had a drug-triggered psychotic episode, and it was the highest conversion rate of any substance studied.
For the wider population, frequency and potency shape risk in a dose-dependent way. Compared with non-users, weekly use is associated with about a 35 percent higher risk of psychosis and daily use with about 76 percent higher risk. Daily use of high-potency cannabis is linked to roughly five times the odds of a psychotic disorder . The single clearest warning sign is a family history of psychosis or bipolar disorder . Specific genes such as COMT, often discussed online, are not reliable for predicting risk in any one person.
The honest summary is two-sided. Most people who use cannabis will not develop psychosis. But a specific, identifiable group carries meaningfully higher risk, and family history plus early, frequent, high-potency use flags most of them.
A warning sign worth knowing
One practical signal is worth every reader knowing. A cannabis experience that does not switch off, where fear, suspicion, or unusual beliefs carry into the next day, is a reason to seek assessment rather than wait it out. In many Indian families the instinct is to manage such episodes quietly at home. When symptoms persist beyond intoxication, that instinct can cost precious time, because early treatment of a first psychotic episode is linked to better outcomes.
Addiction and the myth of "just a plant"
Cannabis can be habit-forming, and rising potency appears to raise that risk. Recent estimates suggest roughly 3 in 10 people who use cannabis meet criteria for cannabis use disorder, with lower figures nearer 1 in 10 among occasional users. Risk climbs with daily use and with starting young. "Natural" and "non-addictive" are not the same thing.
India's legal framework adds a specific twist. Under the NDPS Act, 1985, charas (resin) and ganja (flowering tops) are prohibited, while bhang, prepared from the leaves, sits outside the Act's definition of cannabis and is regulated by individual states rather than banned outright. That carve-out is rooted in cultural and religious tradition, not in a judgement about safety. Read as a green light, it misleads. Bhang is still an intoxicant, and the legal line follows botany and history, not harm.
The cognitive fog: real, but often reversible
Heavy cannabis use is associated with dips in attention, memory and processing speed, the "fog" many regular users describe. The reassuring part is that much of it tends to ease with time off the drug. In a meta-analysis of adolescents and young adults, cognitive deficits linked to cannabis were no longer statistically significant after more than 72 hours of abstinence , which suggests a large share of the fog reflects recent use rather than fixed damage. The caveat is honest: early-onset, heavy, sustained use is where longer-term concern still sits, and that evidence is genuinely mixed.
An honest balance
None of this makes cannabis uniquely dangerous, and overstating the risk helps no one. On several measures cannabis carries lower risk than alcohol or tobacco, and heavy-handed criminalisation brings its own harms. The aim here is accuracy, not panic or prohibition. The lower-risk cannabis use guidelines rest on a plain premise: the only reliable way to avoid all risk is to not use, and for those who will, specific choices lower the odds of harm. If you or someone close to you is going to use, the companion harm-reduction guide walks through those steps in detail.
Conclusion
The line "I used it years ago and I was fine" is understandable, and for many people it is even true. It is simply no longer reliable, because the product has moved. Stronger THC, less CBD, and concentrates that did not exist a generation ago have shifted the risk profile, particularly for young brains and for anyone with a family history of serious mental illness. Knowing this is not a reason to fear cannabis. It is a reason to make an informed choice rather than an outdated one.
Frequently Asked Questions
Is today's cannabis really stronger than before?
Yes. Average THC in seized cannabis roughly quadrupled between 1995 and 2022, and concentrates can reach far higher still. Today's products deliver considerably more THC per use than the plant material of the 1970s and 1980s.
Does cannabis cause schizophrenia?
Not in a simple, one-to-one way. Cannabis raises the risk of psychosis, especially with heavy, high-potency, early-onset use and a family history of psychosis or bipolar disorder. Most users do not develop schizophrenia, but a specific subgroup carries meaningfully higher risk.
Is bhang safer than ganja or charas?
Its legal status differs, but legal is not the same as safe. Bhang sits outside the NDPS Act because it is made from leaves, not because it is proven harmless. It remains an intoxicant and can trigger the same acute effects.
Can cannabis-related memory and concentration problems be reversed?
Often, yes. Studies suggest cognitive deficits linked to cannabis largely diminish after sustained abstinence, frequently within weeks. Early-onset, heavy use is where longer-term effects remain debated.
Is CBD protective against THC's effects?
Possibly, in part. CBD may buffer some of THC's psychoactive and anxiety effects, but the evidence is not settled, and modern high-THC strains contain very little CBD.
Who is most at risk of cannabis-related psychosis?
People with a family history of psychosis or bipolar disorder, those who begin using young, and those who use frequently or use high-potency products. These factors combine, and family history is the clearest single signal.
