Sports-person use anabolic (meaning muscle-building) steroids and other performance-enhancing drugs to build strength and endurance. Such strength and improvement in performance may not be possible with legal and traditional methods.
Some of these drugs are very sophisticated and can evade detection.
Self doubt, lack of confidence, nervousness, stress and depression may force even a strong competitor to resort to these drugs.
A successful athlete is linked with a successful coach. The coach may himself suggest a certain drug to improve performance in order to achieve the success tag.
Peers pressure may also force the usage of these drugs. Those who are habitual may encourage others directly or indirectly.
The expectations of family and friends are often a source of pressure, particularly at the lower levels of competition. Previously successful family members may also create pressure.
Enormous salaries, product endorsements and potential careers outside of the sporting field are some of. the rewards available to the successful athlete. Those hungry for such may resort to short-cuts.
In international competitions, one country's sporting successes over another country are often viewed as proof of ideological or national superiority. This promotes victory by hook or crook, sometimes even by the national authorities.
Some sports-person use certain medicines which may contain banned substances to treat an illness, lack of awareness amongst these result in consumption of illegal drugs.
One-time consumption to experience and further addiction also leads to use of these substances.