Help needed with mind games

[johndoe85]

An aquantice of mine recently started taking pills, they greatly enjoyed the experience but has vowed to never take them again due to what happened to them the following mornings. What happened was that the people who they were with seemed to play with his mind and bring him/her complete confusion, he/she does not fully understand what happened and how they managed it but the things they were doing while he was in the room consisted of talking to each other and then looking at them expecting them to know what is going on, looping the conversations so that topics come up more than once, continually telling them they were messed up, saying specific phrases and describing things in order to create links such as 'the lady loves'.......(cadbury's milk tray). While talking to them they were pointing to things on the wall and saying things under there breath, they were also winking at them. Along with this whenever they left the room they would change things about in the room, such as moving bits of paper into different positions and changing where they were sitting, while this was going on they were also playing dance music on and off and when ever the person changed the way they were sitting they also changed, the list goes on with many other things but i think that is enough to get a general idea. My aquantice is looking for some sort of explination as to why they would do this and why the mind gets so confused, they said it felt like they were doubting everything around him and lost trust in everything, including people and transport, any help here would be much appreciated as one of the people involved in doing this to them was supposed to be a good friend.