Randomized Controlled Trial is the most rigorous study design to test the efficacy and effectiveness of an intervention. Patient preference may negatively affect patient performance and decrease the generalizability of a trial to clinical population. Patient preference trial have particular implications in the field of mental health and addiction since mental health interventions are generally complex, blinding of intervention is often difficult or impossible, patients may have strong preference, and outcome measures are often subjective patient self-report which may be greatly influenced if patient's preference did not match with the intervention received.

In this review, we have surveyed the application of two-stage randomized preference trial with focus on studies in the field of mental health and addiction. The study selection followed the guideline provided by Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews.

Six two-stage randomized preference trials (ten publications) have been identified in the field of mental health field and addiction. In these trials, the pooled dropout rates were 18.3% for the preference arm, and 28.7% for the random arm, with a pooled RR of 0.70 (95% CI, 0.56-0.88; P = 0.010) indicating lower risk of dropout in the preference arm. The standardized preference effects varied widely from 0.07 to 0.57, and could be as large as the treatment effect in some of the trials.

This scoping review has shown that two-stage randomized preference trials are not as popular as expected in mental health research. The results indicated that two-stage randomized preference trials in mental health would be beneficial in retaining patients to expand the generalizability of the trial.

GenerationPMTO is a theory- and evidence-based behavioral parenting program widely implemented in the past three decades. This systematic review and meta-analysis examined the effectiveness of twenty GenerationPMTO studies on parenting and child adjustment among 3893 families in six countries. Hedges' g from studies with pretest-posttest-controlled designs were computed and robust variance estimation (RVE) was used to deal with the effect size dependency. Results showed that GenerationPMTO significantly promoted parenting and child adjustment with moderate to high levels of heterogeneity. Specifically, GenerationPMTO improved parental discipline, parenting monitoring, skill encouragement, child externalizing problems, and child internalizing problems. Subgroup analyses revealed several important moderators, including type of comparison group, measurement, informant, risk of bias, etc. Intervention effects were quite robust across countries and multiple demographic characteristics. No publication bias across studies for parenting and child adjustment was detected. The revised Cochrane risk of bias for randomized trials (RoB 2) procedure was used to assess risk of bias within the included studies. Some studies showed a higher level of risk due to problems with the randomization process, missing data, low measurement quality, and reporting bias. Due to lack of data, we did not examine intervention effects on parental mental health or couple relationship quality. Future studies should test mediation models to understand the mechanisms of change and to identify moderators in order to understand the high levels of heterogeneity in GenerationPMTO studies.

Attention deficit hyperactivity disorder (ADHD) is a common and impairing behavioral health disorder, impacting over 5% of children worldwide. There are multiple evidence-based pharmacological and psychosocial treatments for ADHD, and greater service utilization is associated with improved acute and long-term outcomes. However, long-term outcomes are suboptimal as multimodal treatments are often not accessed and most care ends prematurely. This narrative review discusses barriers to engagement for children and adolescents with ADHD and their families as well as interventions to overcome these barriers. Families face a variety of structural and attitudinal barriers, ranging from cost and access to stigma and low self-efficacy to successfully implement change. There are multiple interventions that may enhance engagement with ADHD care including psychoeducation, integration of behavioral services in general medical settings, telehealth as well as specific adaptations to existing ADHD treatments, such as the use of motivational interviewing or shared decision making. Integration of behavioral health into general medical settings and telehealth have been found in controlled studies to increase access by reducing both structural and attitudinal barriers. Adding motivational interviewing, shared decision making and other engagement interventions to evidence-based ADHD treatments has been found to reduce attitudinal barriers that translates into improved participation and satisfaction while enhancing outcomes. However, little is known about how to promote extended engagement with ADHD services even though a chronic care model for ADHD is recommended.

Parents play a critical role in child and adolescent mental health care and treatment. With the increasing implementation of shared decision-making (SDM) across health settings, there is a growing need to understand the decision support interventions used to promote SDM in child and adolescent mental health services (CAMHS). The overall aim of this review is to identify and examine the existing decision support interventions available for parents. A broad search was conducted using the key concepts "shared decision-making", "parents" and "child and adolescent mental health". Five electronic databases were searched: PsycInfo, Embase, Medline, Web of Science and the Cochrane Library. In addition to these relevant databases, we searched the Ottawa's Inventory of Decision Aids, Children's Hospital of Eastern Ontario website, Google, Google Play and known CAMHS' websites. The search identified 23 interventions available for use with parents. These interventions targeted parents providing care for children with ADHD, ASD, emotional and behavioural problems including depression (EBD), self-harm or universal mental health care. Various modalities including face-to-face, digital and paper-based versions were adopted. The majority of the interventions were able to "present options" (87%) and "discuss the pros and cons" (83%) of treatment. Time, accessibility and appropriateness of the intervention emerged as factors influencing usage and implementation of interventions. Our findings suggest that SDM interventions involving parents have been implemented differently across various presenting mental health difficulties in CAMHS. This review brings awareness of existing parent-involved interventions and has implications for the development, implementation and usage of new interventions.

The goal of this Special Issue is to introduce prevention scientists to an emerging form of healthcare, called precision medicine. This approach integrates investigation of the mechanisms of disease and health-compromising behaviors with prevention, treatment, and cure resolved at the level of the individual. Precision Medicine and its derivative personalized prevention represents a promising paradigm for prevention science as it accounts for response heterogeneity and guides development of targeted interventions that may enhance program effect sizes. If successfully integrated into prevention science research, personalized prevention is an approach that can inform the development of decision support tools (screening measures, prescriptive algorithms) and enhance the utility of mobile health technologies that will enable practitioners to use personalized consumer data to inform decisions about the best type and/or intensity of a prevention strategy for particular individuals or subgroups of individuals. In this special issue, we present conceptual articles that provide a heuristic framework for precision-based, personalization prevention research and empirical studies that address research questions exemplary of a new generation of precision-based personalized preventive interventions focused on children's mental health, behavioral health, and education.