marijuana joint(CNN, May 27) If you're thinking of returning to the weed of your youth to ease the strain of the pandemic, you will soon discover a potent truth -- today's weed is nothing like yesterday's.

Just 20 years ago levels of tetrahydracannabinol, the compound in cannabis known as THC that makes you high, was between 2% and 4% in most marijuana. By 2013, common strains contained 25% THC, with some testing as high as 37%.

Use of weed of any strength has been linked to mental health disorders, and lab experiments have shown that higher does of THC can cause greater memory impairment and temporary psychotic-like symptoms. But few studies have examined how potency levels may affect behavior in real-world populations.

A new study, published Wednesday in the journal JAMA Psychiatry, surveyed more than 1,000 UK residents who reported marijuana use in the past year. The study found high-potency weed users appear to have a significant increase in the likelihood of developing generalized anxiety disorder than those who smoke less robust strains of marijuana. Read more.

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