Drugs and prostitution have been documented to have a direct correlation. In 1978, a study showed that use of drugs by prostitutes appeared to be an "Adaptation and commitment to a deviant social role".
Drug use tended to predate prostitution among low level prostitutes with the connection most likely due to economic necessity. Low level prostitutes tended to use depressants, specifically heroin, as the drug of choice. High class prostitution showed that prostitution predates drug use with stimulants being the drug of choice.
A 1994 study among South London prostitutes showed links between sexual behavior, severity of dependence, and use of heroin, alcohol but rarely, cocaine.
Drug use and Prostitution are intrinsically linked. Especially in the case of street prostitutes, estimates reveal that between 40 and 85 percent of all street prostitutes are drug users.
A study conducted by the National Treatment Agency for Substance Misuse in the UK, has suggested that as 95% of women that are involved with street prostitution in the UK are Heroin or Crack cocaine users.
Prostitutes whom reported a problem with drug use had begun the use of hard drugs at an earlier age (16.2 years old). Because of these early experiences with drugs, these people often begin sex work early in their lives. The average age for people whom engage in sex work with Drug Abuse, was five months younger than those whom have had no problem with drugs (19 years and 2 months old, instead of 19 years 7 months old).
Drug use is also linked with outdoor cruising, which involves cruising around a street looking for clients, and independent drifting which means prostitution from personal phones or Crack houses. 84% of these workers, whom work in this sector, reported problems with drug use, in comparison to the 13%, who work in an indoor-associated escort type agency, such as a sauna, massage parlor, flat or Escort agency.
According to a survey conducted by the Center for Problem-Orientated Policing, more than 70% of Sex workers over 25 have taken Cannabis, Amphetamines, Cocaine, crack cocaine and heroin. Furthermore, for sex workers at 16 to 19 years of age, over 70% of them have experienced cannabis, cocaine, and crack cocaine.