Although overall drug use remains low among women, with men three times more likely than women to use cannabis, cocaine or amphetamines, women are more likely than men to misuse prescription drugs, particularly prescription opioids and tranquillizers (UNODC, 2015). In addition, as described later in the document, there are indications that this ‘gender gap’ might be closing among girls. Yet, as it will become clear, only a very limited number of substance use prevention strategies target girls specifically and it cannot be assumed that existing evidence-based substance use prevention strategies benefit girls as much as they do boys. Moreover, it is estimated that, while one out of three drug users is a woman, only one out of five drug users in treatment is a woman. (UNODC, 2015).