In April 2014, the Jamaica Anti-Doping Commission announced that she would be suspended for 18 months over doping charges, expiring in December that year.

With her personal best of 10.82 seconds in the 100 m, Simpson is ranked 7th among Jamaican women, behind Elaine Thompson-Herah (10.54), Shelly-Ann Fraser-Pryce (10.60), Shericka Jackson (10.65), Merlene Ottey (10.74), Kerron Stewart (10.75), and Veronica Campbell Brown (10.76).

[1] On 14 July 2013, Simpson informed that a urine sample she supplied after competing in the Jamaican national championships in June 2013 had tested positive for the banned stimulant oxilofrine, along with Asafa Powell.

[2] However, after appealing to the Court of Arbitration for Sport (CAS), both athletes' suspensions were reduced to six months expiring in December 2014.

CAS stated that: "They put forward that the offence committed was minor because it was caused by contamination of the food supplement Epiphany D1 by the banned substance oxilofrine.