Editorial: “Improving impacts of mental health treatment on substance misuse and vice versa”

of harmful SU, five subgroups were derived statistically based on sociodemographic characteristics. These subgroups differed in their types and average level of impulsivity as well as errors in predicting rewards, demonstrating that by age 10 childhood vulnerabilities to mental health difficulties and SU are already detectable. These findings reinforce the importance of early detection and profiling of a youth's vulnerabilities to SU and mental health problems to facilitate selective or indicated prevention. Barry and colleagues (12) investigated whether anxiety or depression predicted later SU among high school students residing on or near a Tribal reservation in the U.S. Great Plains.Students' anxiety and depressive symptoms prospectively predicted increased use of alcohol, cannabis and/or prescription opioids a few months later. Their findings suggest that internalizing symptoms may function as a precursor to SU and its consequential problematic sequelae, particularly among youth residing in or near Tribal reservations.Hails and colleagues (13) reported on an alternative prevention strategy, the wellresearched Family Check-Up (designed to enhance parenting skills), in the context of parent SU or mental health challenges. They conducted a 3-month trial of an innovative online version of the Family Check-Up among parents who had lifetime and/or current harmful SU, or current depressive symptoms, and a child between ages 1.5 to 5 years. Specifically among parents who reported adolescent-onset cannabis use, receiving the Family Check-Up was associated with reduced anxiety symptoms. Multiple other clinical trials with longer follow-up periods document additional benefits of the Family Check-Up to parents and their children, including improved mental health and reduced SU (14)(15)(16).In a separate randomized controlled trial of the Family Check-Up, the Youth Risk Index screening tool was utilized in primary care centers to identify 10-13-year-old youth at elevated risk for SU and/or conduct problems who would benefit from prevention services (17). At-risk youth randomized to the Family Check-Up program experienced reduced SU, anxiety, and other risk factors compared to wait-list controls.In this Report Topic, Ridenour and colleagues (18) evaluated psychometric properties of the Youth Risk Index. Their analyses indicated that the Youth Risk Index demonstrates excellent concurrent and predictive validity for SU and conduct problems in both clinical and community samples. Youth Risk Index scores were associated with a broad range of risk factors including personal and neurocognitive characteristics, family and school environments, and depression.Factor analyses suggested that Youth Risk Index items are comprised of three subscales, disinhibition, peer conduct problems, and social contagion, reflecting foundational sources of liability to both mental health difficulties and multiple health risk behaviors.Even after prominent etiological factors are identified, and efficacious screening protocols and prevention programs are developed, barriers to care can limit their population impact (10). Chen and colleagues (19) addressed this challenge by evaluating strategies to encourage engagement and retention in treatment among adolescents of historically marginalized backgrounds who were receiving SU treatment. They reported that providing meal incentives and transportation services to attend sessions was effective in promoting engagement and retention.These findings illustrate a core principle of implementation science: addressing multiple, context-specific barriers is essential to achieving reach and real-world effectiveness.Overall, this Research Topic coincides with growing recognition that effective intervention for co-occurring mental health challenges and harmful SU must be grounded in their shared and interacting etiologies. The U.S. National Institute of Mental Health Research Domain Criteria (RDoC) framework was developed in part to address "an emerging concern that the current diagnostic system was hampering translational research" (20). By emphasizing crossdiagnostic mechanisms across six broad domains of human functioning on mental health and integrating behavioral and neurobiological levels of analysis, RDoC provides a structure for linking etiology to treatment targets. The etiologically informed screening tools and preventive interventions highlighted in this collection reflect this translational vision.Important areas of needed research that this research topic did not address are learning how cultural mores and societal factors contribute to mental health development, SU etiology, and treatment and prevention of potentially poor outcomes (21)(22). As noted during our introductory text, SU disorder and related problems are prominent issues globally; however, even the substances of choice and which drugs are considered acceptable to consume differ widely among regions of the world. At least as diverse are cultural norms regarding fundamental mental health building blocks including emotional expression, shame and stigma, etiology of mental health and illness, discriminatory stereotypes, and coping strategies (22). Barriers and access to treatment, capacity for internet purchase of potent and potentially fatal substances, and quality of health information also vary across cultures and regions, further complicating the equifinality and multifinality of development related to SU and mental health as well as providing opportunities to improve developmental trajectories toward healthy and fulfilling outcomes.In sum, four of the Research Topic's manuscripts illustrate the breadth of advances in evidence-based approaches to understanding etiology of adolescent mental health and risk health behavior and translating this knowledge into practice with their underpinnings aligning with the criteria within the RDoC. The fifth manuscript illustrates the importance of a new and rapidly growing scientific field, implementation science, to improve access to and delivery of mental health services and SU treatment. Continued integration of etiology research, screening, prevention, and implementation strategies offers great promise for reducing the global burden of adolescent mental health problems and SU.