Cannabis isn’t quite what it used to be. Decades ago, cannabis contained relatively low levels of THC—the psychoactive compound responsible for the “high.” In the 1970s, potency hovered around 3–4%. Today, the average THC concentration in many markets has soared well into the 20% range, with some products exceeding that. While this delivers a stronger high, it also raises serious concerns about health risks, particularly the link between cannabis and psychosis.
A recent report published in the Canadian Medical Association Journal revealed that THC concentrations in Canada are now five times higher compared to just two decades ago. Alongside this increase, researchers are observing a rise in psychotic disorders linked to frequent use of high-potency cannabis. The connection between cannabis and psychosis is becoming harder to ignore.
Psychosis can manifest in different ways, ranging from paranoia and delusions to hallucinations and disconnection from reality. For some individuals, cannabis can trigger earlier onset of schizophrenia-spectrum disorders, or worsen existing symptoms. In fact, doctors report that cannabis use often destabilizes patients already struggling with psychotic illnesses. This highlights the complex and potentially harmful relationship between cannabis and psychosis.
Frequent use of cannabis with THC levels above 10% significantly raises risks, especially for young men and those with a history of mental health disorders such as anxiety or depression. For these individuals, the link between cannabis and psychosis can be especially troubling.
Despite the clear association, scientists caution that causality is still being studied. The critical question remains: does cannabis directly cause psychosis in people who otherwise might never have developed it, or does it simply accelerate the onset in those predisposed? Research is ongoing, but what is evident is that cannabis affects individuals differently.
Warning signs of problematic use often go beyond mental health symptoms. Declines in school performance, job instability, or strained relationships can all indicate that cannabis use is shifting into a harmful pattern. For those experiencing changes in mood, perception, or functioning, especially symptoms of psychosis, reducing or eliminating use may be crucial.
The evolving conversation around cannabis and psychosis reflects the need for awareness as cannabis becomes more potent and more widely available. While cannabis may be safe for some, for others, especially vulnerable groups, the risks are significant. Understanding the connection between cannabis and psychosis can help users make informed choices, protect their mental health, and know when it’s time to seek support.
