A Single Psychedelic Drug Trip Can Change Your Personality for Years

So, you decided to "turn on, tune in and drop out" — and you didn't like it. Can you ever fully turn off, tune out and drop back in again?

According to a new review of studies published online in the journal Neuroscience & Biobehavioral Reviews, the answer might be no, dude. Researchers found that individuals who took even a single dose of psychedelic drugs like LSD, "magic" mushrooms and ayahuasca could experience sustained personality changes that lasted several weeks, months or even years — but oftentimes, these changes were for the better. [11 Trippy Facts About 'Magic' Mushrooms]

In the new meta-analysis, researchers from Spain and Brazil looked at the results of 18 previous studies, published between 1985 and 2016, linking psychedelic drug use and personality changes. The researchers focused on papers that looked specifically at serotonergic drugs, or drugs that have structures similar to that of the neurotransmitter serotonin, which helps regulate mood, appetite and various other functions. Such substances bind with serotonin receptors (known as 5-HT receptors), increasing activity in the visual parts of the brain, causing dream-like hallucinations and, for some users, inducing a feeling of transcendence.

The drugs studied in the new meta-analysis primarily included LSD (or lysergic acid diethylamide), psilocybin (a psychedelic compound that occurs naturally in hundreds of species of "magic" mushrooms) and ayahuasca (a psychedelic tea made from plants grown in the Amazon, traditionally consumed for ritual or religious purposes).

Multiple studies of all three drug types found several long-term (perhaps permanent) personality changes in individuals who were administered psychedelic drugs compared to individuals who weren't. In particular, individuals who took small doses of psychedelic drugs in a clinical setting scored higher for a personality trait called openness — the psychological term referring to an appreciation of new experiences — after their drug trip than nonusers did. In some studies, these personality changes resulted in therapeutic, antidepressant effects, and lasted a year or more. (Research for the included studies was conducted in the United States, United Kingdom, Spain, Brazil, and German.)

"This type of research may offer new evidence to the classic discussion on whether personality is or isn’t a constant and stable psychological trait," the researchers wrote.

The question of whether taking psychedelic drugs can result in long-term personality changes has been studied since at least the 1950s, when the U.S. government famously (and sometimes illegally) tested LSD's potential for human mind control. Research linking personality and drug use increased dramatically in the mid-1980s, the authors wrote in the new review, and personality-test-taking methodologies became more accurate. (This is why the authors focused their search on studies published after 1985.)

Significantly more research using larger sample sizes is needed before drawing any definitive conclusions about drugs and personality, the researchers wrote. Given that most of the tested substances are still illegal in the U.S., such an analysis is likely many years away.

Originally published on Live Science.