The systematic review of health outcomes associated with methamphetamine (MA) use among young people by Marshall & Werb  is timely in a period when MA continues to pose challenges to the treatment community in many parts of the world. According to the World Drug Report, MA is the most widely used illicit drug in the world after cannabis . Despite the extent of MA-related problems around the globe, there has been far less systematic study of the health impacts of MA than of other illicit drugs, including heroin and cocaine, especially among young people.
The authors have conducted a thorough review of the research available on MA-using youth. They have carried out careful work highlighting the evidence supporting the more obvious associations between MA use and certain health outcomes, as well as pointing out associations that are less apparent. Their review of the evidence makes it clear that young people, especially young women, who use MA report significantly elevated levels of negative mental health symptoms. In particular, symptoms of psychosis and depression appear to be the most reliably reported of the MA health outcomes. There is evidence that as the frequency of use increases and as injection becomes the preferred route of administration, the severity of these symptoms increases in frequency and severity. Although the examination of the association between MA use and suicidality produced a mix of reports, in combination with the consistent evidence of depression, suicidality for MA-using youth appears to be a substantial risk. Clearly, in early intervention and treatment settings where young MA users are seen, expertise in recognizing and properly addressing the mental health needs of these individuals is a critical priority.
Less is known about other health outcome patterns experienced by MA-using youth. Despite compelling evidence that MA use has significant negative impacts on the health outcomes of older users, including cardiovascular problems, dental problems, human innunodeficiency virus (HIV) and hepatitis and other serious medical complications , Marshall & Werb  note that many of these negative health outcomes are the result of long-term chronic use and, consequently, are not apparent in young people. The authors make a valid assertion that much less evidence exists to support the notion that MA-using youth are at high risk for serious long-term health outcomes, such as HIV, other communicable infections and dental diseases.
The authors suggest that the implications of their systematic review and analysis is that prevention and treatment efforts with young people should address only the health issues for which there is clear evidence of an association with MA use. It is difficult to argue against a recommendation to base prevention and clinical interventions on sound scientific evidence and the results of a systematic review of the health impacts of a substance use disorder on young users. However, from a public health perspective, efforts to educate MA-using youth about the long-term health outcomes associated with MA use are critical to reduce such risks . In general, research supports the effectiveness of increasing the risk perceptions about long-term disease outcomes among this age group, especially in tobacco and HIV-related prevention work [5,6]. Future research with MA-using youth should examine their risk beliefs and attitudes associated with the long-term dangers of MA use to determine how to target adequately prevention efforts aimed at communicating the health risks associated with such use. Overall, the review by Marshall & Werb  makes a significant contribution to the research knowledge on this topic; however, more research is needed to further inform public health responses to MA.