Altering perception has always been one of my favorite subjects to research about. Typically hallucinogens. Hallucinogens range from marijuana to LSD. A widely used hallucinogen is Psilocybin, or mushrooms. Psilocybin has been used for centuries, in many cultures and also as recreational use in modern times.
Psilocybin is found in 200 species of mushrooms and also has psychedelic effects similar to LSD and mescaline. The effects generally involve euphoria, mental hallucinations, visual hallucinations, distorted sense of time, changes in perception, and spiritual experiences. There are also other side effects such as nausea and panic attacks.
I read a study that said large amounts of Psilocybin on typical non-users had a positive effect. It reduced depression and anxiety. It also changes personality changes in people. People were more open and positive in their lives after they had large amounts of Psilocybin. They had never used them and were exposed to high doses their first time.
In perception distortion, the most common distortion is the perception of time. Many users say that time slows down and minutes turn to hours. Users say they gain a stronger connection with the world and their emotions "run" more freely.
These are two articles involving Psilocybin: