section_path: History/Scientific assessment by the World Health Organization/Review process
section_name: Review process
paragraph_text: Review process
  
  The scientific assessment of substances is divided in two steps: pre-review and critical review. According to the WHO:
  
  "The purpose of the pre-review is to determine whether current information justifies an Expert Committee critical review. The categories of information for evaluating substances in pre-reviews are identical to those used in critical reviews."
  
  As compared with the original assessments of cannabis from the 1950s "hastily drawn up on the back of an envelope, the methodology, quality of work and mechanisms for the review of substances considered for international control have evolved substantially" when the ECDD started to collect data towards a pre-review. The ECDD dedicated special attention to the assessment of various products from the Cannabis plant, which were divided as follows:
  
  A total of 3 ECDD meetings were involved with the assessment:
  
  The key finding of the ECDD after these reviews was that:
  
  "cannabis and cannabis resin are not particularly liable to produce ill-effects similar to the effects of the other substances in Schedule IV of the Convention on Narcotic Drugs. In addition, oral preparations of cannabis have shown therapeutic potential for the treatment of pain and other medical conditions such as epilepsy and spasticity associated with multiple sclerosis."
  
  A number of scientists from around the world composed the ECDD: