In the 1950s and ’60s, tons of research funding in the United States and abroad was dedicated to studying the effects that psychedelics have on consciousness, creativity, and spirituality. But psychedelics were outlawed under President Richard Nixon’s Controlled Substances Act. Grant money for psychedelics research quickly dried up, and by the time researchers decades later became curious about the esoteric substances, most prior research had been rendered effectively useless by modern scientific standards. Grant money can still be hard to come by.

Noah Sweat, a program coordinator at the University of Alabama at Birmingham’s School of Public Health, claims that the specter of this politicization continues to influence psychedelics research. “People now that are in positions of authority, either over departments that would be researching [psychedelics] or over the grant-awarding processes, might not have any sort of political objection to the research, but just have kind of absorbed the ambient cultural attitude toward them,” he says.

From 1966: LSD and the third eye

Still, psychedelics have potential dangers. When Olson’s team first gave rats standard, non-micro doses of psychedelics, one potential benefit they observed was a boost in the growth of dendritic spines—small protrusions that boost the activity of communicatory cells—in the part of the brain that controls personality and social behavior. The team expected to see the same effect from a microdose, but instead found almost the opposite. “In the male rats, we saw no change in neuronal structure; and in the females, we actually saw a decrease in dendritic-spine density,” Olson says. To his team, these results were concerning: In some cases, it looked almost like the DMT was having a cytotoxic effect, proving fatal to brain cells.

Olson hopes that by experimentally adjusting different elements of the study, he can figure out a safe way to determine the boundaries of microdosing’s benefits and harms. One factor he’s especially interested in looking into is age, which he says can greatly limit the degree to which a boost in neural plasticity is helpful. Microdosing “during neurodevelopment could be really, really bad,” Olson explains. “On the other hand, the aging brain is a little more susceptible to issues of cytotoxicity, and so that also could be very, very bad. There could be only a very narrow window of time in which they might work.”

Maybe microdosing is the perfect answer for treatment-resistant depression between the ages of 30 and 40, but harmful at any other age. The idea that a tiny psychedelic dose could damage the same brain structures that a full dose reinforces feels counterintuitive, but might be something committed microdosers should consider. So much of what is understood about how various substances work presumes a sort of graded spectrum of effects. Could microdosing, which we still know so little about, be an exception to the rule?

“There’s that saying,” Olson says, “that the difference between a medicine and a poison is the dose.”