WADA had been pressured to review the status of cannabis largely in response to American sprinter Sha'Carri Richardson missing the Tokyo 2020 Olympics because of a positive test for the recreational drug.

Following an extensive review, cannabis will remain on the prohibited list, the 2023 version of which has been approved.

These latest judgements were made at WADA's second Executive Committee meeting of the year, held in Sydney and open to remote participation.

The Executive Committee endorsed the recommendation by the List Expert Advisory Group to prohibit the opioid tramadol in competition.

The delay in implementation is "to provide an additional year for broad communication and education of athletes, their entourage and medical personnel so that there is a better understanding of the practical implementation of tramadol prohibition in competition", WADA said.

It is also claimed this will give support personnel time to address how the safe use of tramadol for clinical purposes fits within anti-doping and sports authorities time to develop educational tools for athletes.

Tramadol has been on WADA's monitoring programme and data gathered through that programme has indicated significant use in sport.

Tramadol abuse, including dose-dependent risks of physical dependence, opiate addiction and overdoses in the general population, is of concern.

It is a controlled drug in many countries for these reasons.

Research studies funded by WADA have also confirmed the potential for tramadol to enhance physical performance.

The International Cycling Union banned the use of tramadol in competitions across all disciplines and categories from March 1 2019 "to protect the riders’ health and safety in light of the side-effects of this substance".

The Court of Arbitration for Sport has this month registered an appeal filed by cyclist Nairo Quintana after the Colombian was sanctioned by the UCI after testing positive for tramadol in blood samples taken on July 8 and 13 during this season's Tour de France.

The judgement on cannabis - which is prohibited in competition only - follows a review that was initiated in September 2021 following requests from "a small number of stakeholders," WADA said.

A group composed of independent experts from nine countries embarked on "a full and thorough review of the status in sport of THC, the main psychoactive component of cannabis".

Its potential to enhance performance, health risk and violation of the spirit of sport was examined by the group.

Cannabis use is against the spirit of sport, in the view of the WADA Ethics Expert Advisory Group.

WADA has also argued that the 2013 increase in the threshold of urinary concentration of THC needed to trigger an adverse analytical finding - now 150 nanograms per milliliter versus 15 before - is "consistent with a significantly impaired athlete or a frequent user".

It is classed as a substance of abuse in the World Anti-Doping Code so carries a significantly reduced penalty if athletes can prove use occurred outside of competition and was unrelated to their performance.

"The question of how THC should be dealt with in a sporting context is not straightforward," WADA director general Olivier Niggli said.

"WADA is aware of the diversity of opinions and perceptions related to this substance around the world, and even within certain countries.

"WADA is also mindful that the few requests for THC's removal from the Prohibited List are not supported by the experts' thorough review.

"We are also conscious that the laws of many countries - as well as broad international regulatory laws and policies - support maintaining cannabis on the List at this time.

"WADA plans to continue research in this area in relation with THC’s potential performance-enhancing effects, its impact on the health of athletes and also in relation to perceptions of cannabis from athletes, experts and others around the world."