IntroductionIt has been hypothesized that there are at least five pathways to adolescent serious and violent offending (SVOs), which include a prenatal risk factor pathway, a personality disorder pathway, an extreme child temperament pathway, a childhood maltreatment pathway, and an adolescent-onset pathway (1). These distinctive pathways have several important criminal justice system policy and public health implications. For the former, one of the most fundamental challenges has been devising and implementing effective intervention policies/programs to reduce recidivism. As well, SVOs frequently have been a major public health concern because their developmental pathways to offending, not uncommonly, are characterized by several physical and mental health risk factors, which also negatively affect their general social functioning. These risk factors include substance abuse, different forms of abuse including physical, sexual, and neglect, family poverty and disruption, and mental health disorders. Fetal alcohol spectrum disorder (FASD) is one mental health disorder that is so strongly over-represented among offender populations that it has been hypothesized to represent the SVO prenatal risk facto pathway (1). Like other pervasive developmental disorders, FASD is a complicated phenomenon; however, its etiology is less controversial because it is directly caused by the toxic effects of ethanol concentrations in alcohol on the development of the fetal brain. Frequent consumption of higher amounts of alcohol or binge drinking during the second trimester of pregnancy are two ways in which the likelihood of FASD is increased. Given that FASD too is a spectral disorder, its developmental impact on SVOs is very likely varied and mediated by other risk and protective factors.In Canada and other countries with substantial Aboriginal and First Nations populations (e.g., Australia and New Zealand), FASD is a fundamental health and mental health policy issue (2). Although FASD is not easily diagnosable, primarily because current tests are time consuming and costly, FASD has been reported to be disproportionately present among Aboriginal youth in both Canada (2) and Australia (3). Another policy theme is that FASD has likely been under-diagnosed for a variety of reasons but primarily because of resource limitations. It is difficult to obtain and validate prevalence estimates across different countries; yet few health officials in countries such as Canada, Australia, New Zealand, and the United States deny that FASD is a critical public health concern, generally, and for youth and adult criminal justice systems, in particular.In this study, a sample of incarcerated adolescent offenders (n = 514) were asked whether they had been told they had been diagnosed with FASD. File data also was utilized to assess or support the FASD assertion, though, this data too was subject to incomplete reporting. Additional criminogenic risk factors, including abuse, substance use, placement in foster care, and low self-control, were included to examine whether these factors mediated the relationship between FASD and different criminal offending outcome measures. As well, both criminal justice and public health systems' FASD-related costs were considered.Outcomes associated with FASDFASD has been causally related to neuro-cognitive deficits involving executive functioning, behavioral regulation problems, learning, and other mental and physical health problems (4,5). Nonetheless, the prevalence of FASD diagnoses in general populations has been estimated to be very low. Sampson et al. (6), for example, estimated that less than 1% of live births were afflicted with some form of alcohol-related neuro-developmental disorder. In effect, FASD does not appear to be a pervasive social/health issue. However, in countries such as Canada, the prevalence of FASD within certain criminogenic sub-populations (e.g., youth on probation) has been estimated to be as high as 30% (7), and similarly high among youth in forensic inpatient centers (8). …