Juvenile probation officers delivering an intervention for substance use significantly reduces adolescents' risky sexual behaviours.

BACKGROUND: Risky sexual behaviour (RSB) is a serious public health problem for adolescents. We examined whether a contingency management intervention implemented by juvenile probation officers (JPOs) targeting substance use also impacted RSB. METHODS: A total of 218 adolescents on probation were randomly assigned to contingency management or to probation as usual. RESULTS: The substance use intervention delivered by JPOs reduced rates of RSB over time (ß =-0.32, P =0.041 at 6months; ß =-0.32, P =0.036 at 9months). CONCLUSIONS: Adolescents receiving a substance use intervention from JPOs demonstrated reduced/prevented RSB. Interventions targeting single risk behaviours in juvenile probation populations should measure changes in other risk behaviours . Under-resourced communities lacking clinicians might consider JPOs delivering interventions.

Evidence Base Update of Psychosocial Treatments for Adolescents with Disruptive Behavior.

OBJECTIVE: This article expands the review of psychosocial treatments for adolescents with disruptive behavior (DB), published previously by this journal. That earlier review focused on DB treatment studies published 1966-2014; the current paper updates the evidence base by incorporating DB treatment studies published 2014-2021. METHOD: A literature search and screening process identified 63 new studies for inclusion in this updated review. The 63 new studies were combined with 86 studies from the prior review and evaluated using Journal of Clinical Child and Adolescent Psychology level of support criteria, which classify studies as well established, probably efficacious, possibly efficacious, experimental, or of questionable efficacy based on the evidence. RESULTS: In total, 3 well-established, 7 probably efficacious, and 10 possibly efficacious treatments for adolescents with DB were identified. Further, 52 treatments were classified as experimental and 22 treatments were determined to have questionable efficacy. CONCLUSIONS: There continues to be a large body of literature building the evidence base for treatments of adolescent DB. With a few exceptions, treatments falling into the top three evidence levels utilized more than one theoretical approach, enhancing each treatment's ability to target DB from multiple angles. Key advances include broad representation of various demographic groups, countries of origin, treatment settings, and provider types in this body of research. Despite these advances, more research is needed to address key gaps in the field, including the need for more studies on treatments tailored to adolescents with DB who are not yet involved with the juvenile justice system.

JUVENILE PROBATION OFFICER PERCEPTIONS OF PARENTAL INVOLVEMENT IN JUVENILE PROBATION AND WITH CONTINGENCY MANAGEMENT.

Probation is a common sanction for youth substance users, and as such, juvenile probation officers (JPOs) shoulder much of the burden for treatment and rehabilitation. To improve youth outcomes and alleviate some of the burden, JPOs may seek parental involvement in the probation and substance use desistance processes. Using focus group data, we analyzed JPO perceptions of the role parents play in contingency management (CM)-an incentive system designed to produce and reward decreased substance use-and whether they perceived any value in CM. We found that most JPOs perceived parental involvement as critical to the success of both substance use treatment and CM for youth. Our findings also suggest JPOs found parental involvement in CM valuable given that CM was employed on nonstudy clients and future clients. This has implications for the practicality and sustainability of CM as a youth probation intervention.

Examining the measurement precision of behavior problems among a sample of primarily rural youth on juvenile probation and their parents.

Accurate and timely intervention in the justice system is particularly critical in rural communities, given documented barriers to accessible, evidence-based services for youth. As youth in the juvenile justice system have a high prevalence of behavioral health needs, accurate assessment of those needs is a critical first step in linking youth to appropriate care. The goal of the current study is to examine the reliability of a brief assessment (the Brief Problem Checklist [BPC]) among a sample of 222 justice-involved youth and their caregivers who primarily reside in rural communities in the United States. Using a series of reliability analyses and tests of agreement, we examined whether youth and caregiver BPC produces reliable scales, the strength of the convergence among each of the BPC scales, and youth and caregiver agreement on the BPC scales. Findings support the reliability of the BPC, but not inter-rater reliability. Poor agreement between youth and caregiver reports exists for both youth internalizing and externalizing problems. Additionally, the BPC was significantly related to several theoretically relevant constructs, including treatment, substance use disorder severity, and family history of substance use. These findings lend merit to discussions about the need for more research on the reliability and validity of assessment instruments before their widespread use in guiding youth- and agency case planning decisions, along with informing conclusions about program effectiveness.

Performance of a Supervisor Observational Coding System and an Audit and Feedback Intervention.

Workplace-based clinical supervision is common in community based mental health care for youth and families and could be a leveraged to scale and improve the implementation of evidence-based treatment (EBTs). Accurate methods are needed to measure, monitor, and support supervisor performance with limited disruption to workflow. Audit and Feedback (A&F) interventions may offer some promise in this regard. The study-a randomized controlled trial with 60 clinical supervisors measured longitudinally for 7 months-had two parts: (1) psychometric evaluation of an observational coding system for measuring adherence and competence of EBT supervision and (2) evaluation of an experimental Supervisor Audit and Feedback (SAF) intervention on outcomes of supervisor adherence and competence. All supervisors recorded and uploaded weekly supervision sessions for 7 months, and those in the experimental condition were provided a single, monthly web-based feedback report. Psychometric performance was evaluated using measurement models based in Item Response Theory, and the effect of the SAF intervention was evaluated using mixed-effects regression models. The observational instrument performed well across psychometric indicators of dimensionality, rating scale functionality, and item fit; however, coder reliability was lower for competence than for adherence. Statistically significant A&F effects were largely in the expected directions and consistent with hypotheses. The observational coding system performed well, and a monthly electronic feedback report showed promise in maintaining or improving community-based clinical supervisors' adherence and, to a lesser extent, competence. Limitations discussed include unknown generalizability to the supervision of other EBTs.

Randomized trial of a diversion program for property offenders with drug use.

Purpose: This paper reports findings from a randomized controlled trial of a front-end diversion program for prison-bound individuals with property crime convictions, concurrent substance use problems, and no prior violent crime convictions. Methods: Two counties in Oregon participated in the trial, labeled "County A" and "County B." Across counties, 272 individuals (mean age = 32.7 years; 67.6% male) were recruited and randomized to receive either the diversion program (Senate Bill 416 [SB416]) or probation as usual (PAU). The primary outcome was recidivism, defined as any arrest, conviction, or incarceration for a new crime within three years of diversion from prison. Results: In County A, SB416 did not outperform PAU on any recidivism outcome. However, in County B, SB416 yielded significantly greater improvements across various configurations of the arrest, conviction, and incarceration outcomes, relative to PAU. Conclusions: SB416 can yield reduced recidivism when implemented in a setting like County B, which when compared to County A, had fewer justice system resources and a limited history of cross-system collaboration. More research on SB416 is needed, including an examination of its mechanisms of change and its cost-effectiveness relative to standard criminal justice system processing.

Randomized Controlled Trial of an Integrated Family-Based Treatment for Adolescents Presenting to Community Mental Health Centers.

Most adolescents presenting to community mental health centers have one or more comorbidities (internalizing, externalizing, and substance use problems). We evaluated an integrated family-based outpatient treatment for adolescents (OPT-A) that can be delivered in a community mental health center by a single therapist. A sample of 134 youth/families were randomized to receive OPT-A or usual services, delivered at the same public sector mental health center. Repeated, multi-informant assessments occurred through 18-months post-baseline. At baseline, the sample displayed low internalizing symptoms, moderate substance use, and high externalizing problems. Compared to usual services, OPT-A had effects on abstinence rates, retention, motivation, parent involvement, and satisfaction, but not on internalizing or externalizing problems. While OPT-A achieved some key improvements for youth who present to community mental health centers, and families were satisfied with treatment, continued work is necessary to examine treatments for comorbidity while balancing treatment feasibility and complex strategies to boost treatment effectiveness.

Factors promoting and impeding HIV testing among adolescents in juvenile drug court.

A randomized pilot study compared Risk Reduction Therapy for Adolescents (RRTA) to treatment as usual (TAU); the present study examined whether intervention condition influenced HIV testing, barriers to HIV testing, and HIV communication among adolescents involved in juvenile drug courts overall and by sexual experience. Of 105 participants, 13.3% had HIV pre-treatment testing, whereas 27.2% (of 92 participants) indicated follow-up HIV testing. Sexually active youth in RRTA (but not in TAU) reported a significant increase in HIV testing over time. RRTA demonstrated the greatest increase in HIV testing (8% pre-treatment to 44% follow-up), but not significantly more than TAU. Prevalence of barriers to HIV testing were observed at consistent rates among adolescents who did not get tested for HIV within either treatment condition. Adolescents in both conditions reported increased communication about HIV at follow-up. HIV testing was positively associated with perceived need for testing and testing resource accessibility. Stigma remained a barrier to testing at follow-up for RRTA (22%) and TAU (21%) participants. The RRTA intervention increased HIV testing and both interventions increased adolescents' communication about HIV; however, barriers persisted, warranting treatment modification.

Association of Mental Health Symptoms and Peer Behaviors with Risk for Substance Use and Condomless Sex among Youth in Juvenile Drug Court.

Juvenile drug courts are a growing response to adolescent substance use, but a better understanding of modifiable risk factors is needed to improve program outcomes. Youth's mental health symptoms and peers' activities may impede the effectiveness of these "therapeutic" courts. In a unique longitudinal sample of 105 adolescents involved in juvenile drug court, we find elevated internalizing symptoms and deviant behavior of peers were each associated with increased risk of alcohol and marijuana use. Similar effects were seen on risk for condomless sex. Mental health and peer behaviors should be intervention targets for evidence-based juvenile drug court programming.

Parent and Youth Engagement in Court-Mandated Substance Use Disorder Treatment.

While juvenile drug courts (JDCs) require treatment participation, youth and parent engagement in treatment cannot be mandated. We compared youths' and parents' self-reports of engagement in Risk Reduction Therapy for Adolescents (RRTA) and Treatment as Usual (TAU) in JDCs. Parents and youth receiving RRTA were more likely than those receiving TAU to report high engagement in treatment. High parent engagement in RRTA early in treatment predicted fewer missed appointments and lower youth substance use at 3 months. Emphasizing therapeutic techniques that increase parent engagement, as utilized in RRTA, could lead to improved participation and clinical outcomes in court-mandated treatment settings.

Evidence-Based Psychosocial Treatments for Adolescents With Disruptive Behavior.

This article updates the earlier reviews of evidence-based psychosocial treatments for disruptive behavior in adolescents (Brestan & Eyberg, 1998; Eyberg, Nelson, & Boggs, 2008), focusing primarily on the treatment literature published from 2007 to 2014. Studies were identified through an extensive literature search and evaluated using Journal of Clinical Child and Adolescent Psychology (JCCAP) level of support criteria, which classify studies as well-established, probably efficacious, possibly efficacious, experimental, or of questionable efficacy based on existing evidence. The JCCAP criteria have undergone modest changes in recent years. Thus, in addition to evaluating new studies from 2007 to 2014 for this update, all adolescent-focused articles that had been included in the 1998 and 2008 reviews were reexamined. In total, 86 empirical papers published over a 48-year period and covering 50 unique treatment protocols were identified and coded. Two multicomponent treatments that integrate strategies from family, behavioral, and cognitive-behavioral therapy met criteria as well-established. Summaries are provided for those treatments, as well as for two additional multicomponent treatments and two cognitive-behavioral treatments that met criteria as probably efficacious. Treatments designated as possibly efficacious, experimental, or of questionable efficacy are listed. In addition, moderator/mediator research is summarized. Results indicate that since the prior reviews, there has been a noteworthy expansion of research on treatments for adolescent disruptive behavior, particularly treatments that are multicomponent in nature. Despite these advances, more research is needed to address key gaps in the field. Implications of the findings for future science and clinical practice are discussed.

Transdiagnostic Motivational Enhancement Therapy to Reduce Treatment Attrition: Use in Emerging Adults.

Improving outcomes of youth with mental health (MH) needs as they transition into adulthood is of critical public health significance. Effective psychotherapy MH treatment is available, but can be effective only if the emerging adult (EA) attends long enough to benefit. Unfortunately, completion of psychotherapy among EAs is lower than for more mature adults (Edlund et al., 2002; Olfson, Marcus, Druss, & Pincus, 2002). To target the high attrition of EAs in MH treatment, investigators adapted a developmentally appropriate brief intervention aimed at reducing treatment attrition (TA) in psychotherapy and conducted a feasibility study of implementation. The intervention employs motivational interviewing strategies aimed at engaging and retaining EAs in outpatient MH treatment. Motivational enhancement therapy for treatment attrition, or MET-TA, takes only a few sessions at the outset of treatment as an adjunct to usual treatment. Importantly, it can be used for TA with psychotherapy for any MH condition; in other words, it is transdiagnostic. This article presents the first description of MET-TA, along with a case example that demonstrates important characteristics of the approach, and then briefly describes implementation feasibility based on a small pilot randomized controlled trial.

Multisystemic Therapy for Emerging Adults With Serious Mental Illness and Justice Involvement.

Most serious mental illnesses (SMI) have onset by emerging adulthood and SMI can impair adolescents' transitions into healthy, productive adults. Emerging adults (EAs) with SMI are at high risk for justice involvement, and rates of recidivism are greater for offenders with SMI than without. These EAs are frequently multi-system involved (e.g., aging out of foster care; both juvenile and adult arrests; prison reentry). Few interventions, however, have focused specifically on EAs, and no interventions have focused on reducing recidivism in EAs with or without SMI. Multisystemic Therapy for Emerging Adults (MST-EA) is an adaptation of standard MST (for adolescent antisocial behavior) that was specifically designed for EAs with SMI and justice involvement. This paper provides the first description of MST-EA, including clinical outcome data on pilot cases and an extensive case example. To date, 57 cases have been treated with MST-EA. Success at discharge was demonstrated on main outcomes (rearrest and mental health) and other functional outcomes. Clinical data on pilot cases is promising and supports further research to assess long-term outcomes and effectiveness.

Juvenile Justice, Mental Health, and the Transition to Adulthood: A Review of Service System Involvement and Unmet Needs in the U.S.

Although adolescents are the primary focus of juvenile justice, a significant number of young people involved with this system are considered transition age youth (i.e., 16-25 years of age). The aim of this review is to summarize the specific needs of transition age youth with mental health conditions involved with the juvenile justice system, identify the multiple service systems relevant to this group, and offer recommendations for policies and practice. A comprehensive search strategy was used to identify and synthesize the literature. Findings highlight the paucity of research specific to transition age youth. Thus, we also summarized relevant research on justice-involved adolescents, with a focus evaluating its potential relevance in the context of the unique milestones of the transition age, including finishing one's education, setting and working towards vocational goals, and transitioning from ones' family of origin to more independent living situations. Existing programs and initiatives relevant to transition age youth with mental health conditions are highlighted, and nine specific recommendations for policy and practice are offered.

ADHD and risky sexual behavior in adolescents: conduct problems and substance use as mediators of risk.

BACKGROUND: Recent studies have linked attention-deficit/hyperactivity disorder (ADHD) to elevated rates of risky sexual behavior (RSB) in adult samples. The current study tested whether ADHD symptoms were associated with RSB among adolescents, and examined comorbid conduct problems and problematic substance use as joint mediators of this association. METHODS: ADHD symptoms, conduct problems (oppositional defiant disorder/conduct disorder symptoms), problematic alcohol use (alcohol use disorder symptoms, alcohol use frequency), problematic marijuana use (marijuana use disorder symptoms, marijuana use frequency), and RSB were assessed among an ethnically diverse cross-sectional sample of adolescents (N = 115; mean age = 14.9 years) involved in the juvenile justice system. RESULTS: Bootstrapped mediation models revealed an initial association between ADHD symptoms and RSB that was accounted for fully by the influence of problematic alcohol and marijuana use, but not conduct problems. A follow-up multiple groups mediation analysis demonstrated that the relationship between ADHD symptoms and RSB emerged only among youth with clinically elevated conduct problems, and that problematic marijuana use fully accounted for this relationship. Hyperactive/impulsive, but not inattentive, symptoms were related to RSB, although the pattern of indirect effects was consistent with the multiple groups analysis. CONCLUSIONS: The association between ADHD and adolescent RSB is restricted to youth with elevated comorbid conduct problems and reflects the contributions of comorbid marijuana use problems, and to a lesser extent alcohol use problems. Early identification and treatment of these comorbid conditions may be important for the prevention of negative sexual health outcomes among youth with ADHD.

Risk Reduction Therapy for Adolescents: Targeting Substance Use and HIV/STI-Risk Behaviors.

This paper describes a family-based intervention for addressing both substance use and unprotected sexual behavior in adolescents presenting for outpatient substance use treatment. The intervention combines contingency management (CM) for adolescent substance use, which is a behavioral intervention modeled on the Community Reinforcement Approach, with a sexual risk reduction protocol that mirrors aspects of the CM model. As a family-based intervention, caregivers attend every session and actively collaborate with the therapist to address their youth's behavior problems. The treatment is criterion-based with treatment duration determined by the youth's achievement of reduced substance use and unprotected sexual behavior goals. A case study describes the implementation of this treatment with an adolescent presenting a history of polysubstance use and unprotected sexual intercourse. Following the adolescent and caregiver's participation in weekly sessions, the adolescent demonstrated improvements in substance use, unprotected sexual behavior, and other behavior problems. Clinical summary data from two outpatient clinics reveal similar positive outcomes for youth receiving the intervention. This paper illustrates the potential utility of an integrated treatment approach targeting substance use and unprotected sexual behavior in an adolescent population.

Leveraging Parents and Peer Recovery Supports to Increase Recovery Capital in Emerging Adults With Polysubstance Use: Protocol for a Feasibility, Acceptability, and Appropriateness Study of Launch.

BACKGROUND: Emerging adults (aged 18-26 years) are the most at-risk yet underserved age group among people with substance use disorder, especially rural emerging adults, and polysubstance use is common. Recovery capital is lower among emerging adults than older adults, and evidence-based treatments are typically unavailable or not developmentally tailored, especially in rural areas. Both supportive parents (or parental figures) and peer recovery support services (PRSS) can be leveraged to better support these emerging adults. Previous research indicates parents can be engaged to deliver contingency management (CM), an extensively researched evidence-based intervention for substance use. OBJECTIVE: This protocol describes a funded pilot of Launch, a novel, scalable service package that pairs web-based coaching for parents to deliver CM for emerging adults (CM-EA) at home and in-person PRSS with educational and vocational goal setting. Specifically, this protocol describes feasibility, acceptability, and appropriateness testing (implementation-related outcomes) and steps taken to prepare for a future large-scale trial of Launch. METHODS: Upon the recruitment of 48 emerging adult and parent pairs from sites serving primarily rural clients, participants will be randomized into 1 of 3 conditions for this randomized controlled trial: virtual parent coaching to deliver CM-EA, in-person PRSS for emerging adults, or both sets of services. Emerging adult eligibility includes polysubstance use, a substance use disorder, and availability of a consenting parent. Emerging adults will be interviewed at baseline and 6 months about substance use, quality of life, recovery capital, parental relationship, and Launch implementation-related outcomes (6-month follow-up only). Parents, peer workers delivering PRSS, and parent CM-EA coaches will be interviewed about implementation-related outcomes at the end of the study period. Peer workers and CM-EA coaches will be asked to complete checklists of services delivered after each session. Finally, payers and providers will be interviewed for additional insights into Launch implementation and to identify key outcomes of Launch. Data analysis for emerging adult outcomes will be primarily descriptive, but parent CM-EA training adherence will be assessed using nested mixed-effects regression models of repeated measures. RESULTS: Launch is currently ongoing, with funding received in August 2023, and is expected to end in September 2025, with data analysis and results in December 2026. Participants are expected to begin enrolling in June 2024. CONCLUSIONS: While this pilot is limited by the small sample size and restriction to emerging adults with an involved parent, this is mitigated by the study's strengths and is appropriate for the pilot stage. Launch uses an innovative combination of existing strategies to generate better outcomes for emerging adults while remaining scalable. This pilot will provide insights into the feasibility and acceptability of Launch from the perspectives of service recipients, providers, and payers to inform a larger-scale effectiveness trial. TRIAL REGISTRATION: ClinicalTrials.gov NCT06414993; https://clinicaltrials.gov/study/NCT06414993. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/60671.

Implementation outcomes from a pilot study of training probation officers to deliver contingency management for emerging adults with substance use disorders.

INTRODUCTION: Emerging adults (EAs) in the criminal legal system are at high risk for substance use and related negative outcomes. EAs also have low levels of engagement in treatment services, a pattern exacerbated for those living in rural communities. This pilot study investigated implementation outcomes of task-shifting an evidence-based substance use intervention, via a developmentally targeted program, provided by probation officers (POs) to selected EA clients. METHODS: Ten POs recruited from two counties in Oregon who provide services to rural clients were trained and supported in delivering contingency management for EAs (CM-EA) to 17 EAs on their current caseloads. The pilot took place entirely during the COVID-19 pandemic. POs submitted session audiotapes and checklists from meetings with participating EA clients and participated in focus groups. EA clients completed baseline interviews and agreed to have their adult criminal records collected. Ten semi-structured interviews were completed with probation/parole administration and staff from four rural counties across three states highly impacted by the opioid epidemic about the barriers and facilitators for delivering a program like CM-EA in their offices. RESULTS: Based on self-reports and observational coding, POs demonstrated fidelity and adoption as they delivered all CM-EA components and engaged in CM-EA quality assurance protocols. Penetration was demonstrated by the selection of EAs reflecting the demographics of their local offices (i.e., White, non-Hispanic, balanced across sex), struggling with polysubstance use, and primarily holding felony convictions. Emerging themes from focus groups and interviews revealed feasibility, acceptability, and appropriateness of CM-EA, including use with clients not currently in the research program and reported intentions to continue CM-EA use. Barriers for future use include those found for the delivery of other programs in rural areas such as resource limitations. CONCLUSIONS: There is initial support for the implementation outcomes related to task-shifting a program like CM-EA to POs, particularly those serving rural clients, to increase access to evidence-based substance use services for EAs. Future research with larger samples and multiple follow-ups will allow for effectiveness testing and further program refinement for this high-priority population.

Linkage facilitation services for opioid use disorder: Taxonomy of facilitation practitioners, goals, and activities.

INTRODUCTION: This article proposes a taxonomy of linkage facilitation services used to help persons with opioid use disorder access treatment and recovery resources. Linkage facilitation may be especially valuable for persons receiving medication for opioid use disorder (MOUD) given the considerable barriers to treatment access and initiation that have been identified. The science of linkage facilitation currently lacks both consistent communication about linkage facilitation practices and a conceptual framework for guiding research. METHODS: To address this gap, this article presents a taxonomy derived from expert consensus that organizes the array of practitioners, goals, and activities associated with linkage services for OUD and related needs. Expert panelists first independently reviewed research reports and policy guidelines summarizing the science and practice of linkage facilitation for substance use disorders generally and OUD specifically, then met several times to vet the conceptual scheme and content of the taxonomy until they reached a final consensus. RESULTS: The derived taxonomy contains eight domains: facilitator identity, facilitator lived experience, linkage client, facilitator-client relationship, linkage activity, linkage method, linkage connectivity, and linkage goal. For each domain, the article defines basic domain categories, highlights research and practice themes in substance use and OUD care, and introduces innovations in linkage facilitation being tested in one of two NIDA-funded research networks: Justice Community Opioid Innovation Network (JCOIN) or Consortium on Addiction Recovery Science (CoARS). CONCLUSIONS: To accelerate consistent application of this taxonomy to diverse research and practice settings, the article concludes by naming several considerations for linkage facilitation workforce training and implementation.

Linkage facilitation for opioid use disorder in criminal legal system contexts: a primer for researchers, clinicians, and legal practitioners.

At the intersection of drug policy, the opioid crisis, and fragmented care systems, persons with opioid use disorder (OUD) in the United States are significantly vulnerable to contact with the criminal legal system (CLS). In CLS settings, provision of evidence-based treatment for OUD is variable and often secondary to punitive approaches. Linkage facilitation at every touch point along the CLS Sequential Intercept Model has potential to redirect persons with OUD into recovery-oriented systems of care, increase evidence-based OUD treatment connections, and therefore reduce CLS re-exposure risk. Research in this area is still nascent. Thus, this narrative review explores the state of the science on linkage facilitation across the varied CLS contexts, including general barriers, facilitators, and opportunities for using linkage facilitation for OUD treatment and related services. Following the CLS Sequential Intercept Model, the specific CLS contexts examined include community services, police encounters, the courts (pre- and post-disposition), incarceration (pre-trial detention, jail, and prison), reentry (from jails, prisons, and unified systems), and community supervision (probation and parole). Examples of innovative linkage facilitation interventions are drawn from the Justice Community Opioid Innovation Network (JCOIN). Areas for future research and policy change are highlighted to advance the science of linkage facilitation for OUD services in the CLS.