Psilocybin may reduce alcohol and tobacco use in addicted samples. Ibogaine and ayahuasca have shown promise in the treatment of various addictions through observational studies. Ketamine has been used to treat alcohol dependence and reduces cocaine self-administration in the human laboratory. Randomised controlled trials are greatly needed to further test the efficacy of all of these compounds. Psychedelic drugs may have their therapeutic qualities due to anti-depressant effects, stimulating neuroplasticity and long-term psychological changes.