If You’re Still Smoking Weed at 30, Scientists Have Bad News
As cannabis legalization spreads across the U.S. and other countries, more adults are using marijuana regularly—often assuming it’s a harmless habit. However, emerging research suggests that long-term cannabis use, particularly beyond age 30, may come with significant cognitive, mental, and physical health risks. Here’s what scientists are warning about.
Cognitive Decline and Memory Problems
A 2022 study published in The American Journal of Psychiatry found that persistent cannabis use from adolescence into adulthood was linked to lower IQ and poorer memory and attention. While some effects may stabilize after quitting, heavy, long-term users in their 30s and beyond showed slower processing speeds and reduced executive function—key skills for decision-making and problem-solving.
Increased Risk of Mental Health Disorders
Though cannabis is often touted as a stress reliever, frequent use in adulthood is associated with higher rates of anxiety, depression, and even psychosis in susceptible individuals. A Lancet Psychiatry study found that daily high-potency (high-THC) cannabis use increased the risk of psychotic disorders by nearly five times compared to non-users. For those with a family history of mental illness, the risks are even greater.
Heart and Lung Concerns
Many assume smoking weed is safer than cigarettes, but research suggests otherwise. A 2023 study in JAMA linked regular cannabis smoking to higher risks of heart attack and stroke, particularly in middle-aged adults. Additionally, chronic marijuana smoking can lead to bronchitis and lung irritation, with some studies showing it may contribute to emphysema-like symptoms over time.
Impact on Motivation and Life Outcomes
The stereotype of the “lazy stoner” may have some scientific backing. Research in Clinical Psychology Review indicates that long-term cannabis users are more likely to experience lower educational attainment, reduced career success, and financial instability. While correlation doesn’t equal causation, experts suggest that prolonged use may sap motivation and hinder personal growth.
Is There a Safe Way to Consume?
Not all cannabis use is equally risky. Occasional, low-THC use (such as edibles or CBD-dominant products) appears to have fewer negative effects than daily high-THC smoking. However, experts warn that normalization of heavy use in adulthood could lead to overlooked health consequences.
The Bottom Line
While cannabis may be less harmful than alcohol or tobacco for some, science suggests that continuing heavy use past 30 comes with real risks—especially for brain health, mental well-being, and cardiovascular function. If you’re concerned, cutting back or switching to lower-potency products may help mitigate some of these effects.
