Depression and anxiety are two of the world’s most common neuropsychiatric conditions. There has been some success in treating depression and anxiety by using classic psychedelic drugs to cause positive changes in psychological well-being. Depression and anxiety are often correlated to self-rumination and a heightened sense of self, making sufferers unable to withdraw from repetitive negative self-referenced thought patterns. Some researchers hypothesize that the therapeutic effects of psychedelics come from their acute subjective effects, specifically ego-dissolution. This systematic review aimed to investigate what clinical studies can support this hypothesis. By reviewing five studies that examined this correlation, this review found that the majority of the studies could present a moderate correlation. This suggests a negative correlation between the degree of ego-dissolution and the therapeutic improvements in disorders with a heightened sense of self.