From the abstract: "After adjusting for [factors including] childhood depression, we found no significant associations between lifetime use of psychedelics and increased likelihood of [mental health problems in the past year]."

Yet: "Psychedelic users were more likely than non-users to report a depressive episode before age 18."

Taken together, these are curious findings, because they're deliberately ignoring something that turned out to be a clear correlation, even one that might be the result of a causality in the reverse direction to one that might be otherwise presumed.