Evidence of medical marijuana's pain mitigating effects is generally conclusive. Detailed in a 1999 report by the Institute of Medicine, "the available evidence from animal and human studies indicates that cannabinoids can have a substantial analgesic effect". In a 2013 review study published in Fundamental & Clinical Pharmacology, various studies were cited in demonstrating that cannabinoids exhibit comparable effectiveness to opioids in models of acute pain and even greater effectiveness in models of chronic pain.