I had a friend who was self-medicating her anxiety and bipolar disorder (as I understand it, she only found out about the bipolar disorder some time after she quit smoking). She was pursuing a bachelor's degree at the time and was highly promising in her field, according to her supervisors. But after six months of use, all her academic achievements turned into failures. Plus, during depressive phases, cannabis sometimes made her feel even worse. In the end, after a year of smoking weed, she quit because she realized it was seriously affecting her brain and abilities. And that she could end up completely screwing up her life.