Its based on a lot of stuff. My experiences, my friends experiences, the scientific literature.
I get that everyone loves to say that ketamine and mushrooms are so magical but if you read into these studies they urge extreme caution. The patients need to be careful screened (never mind that study participants self select from previous drug use), the dosages are exact, and they are monitored by professionals. Plus, there is 0 evidence that ketamine helps long term and a TON of evidence it causes severe addiction and withdrawal
Point is, illicit drugs are not some magical thing that will solve your problems. In fact, they will make your life a hell of a lot worse the majority of the time.