Measures of Suicidal Thoughts and Behaviors in Children and Adolescents: A Systematic Review and Recommendations for Use in Clinical and Research Settings.

Empirically supported measures of suicidal thoughts and behaviors (STBs) are needed to serve as reference outcomes for suicide risk screening tools and to monitor severity and treatment progress in children and adolescents with STBs. The present paper systematically reviewed existing measures of STBs in youth and studies evaluating their psychometric properties and clinical utility. Measures were then evaluated on reliability, validity, and clinical utility. Sixteen articles (20 independent samples) were found with psychometric data with youth samples for eight measures. Interview-based measures were found to have the strongest psychometric support and clinical utility. Significant limitations exist for all self-report measures due to inherent characteristics of these measures that cannot be remedied through additional psychometric study. There is an urgent need for the development and validation of new self-report measures of STBs, particularly for preadolescent children, sexual and gender minority youth, and racial/ethnic minority youth.

Chronic inflammation is associated with worsening working memory performance: Preliminary evidence from a diverse, longitudinal cohort of adolescents and young adults.

Many depressed individuals experience cognitive difficulties that persist when depression is in remission. Inflammation is hypothesized to play a role in cognitive dysfunction in depression; however, many aspects of this relationship are not well characterized. The current study examined whether inflammation is associated with specific cognitive deficits in individuals with a history of depression and with progressively worsening working memory over time. Adolescents who participated in a prospective, longitudinal study of adolescent-onset depression were recruited to complete a follow-up cognitive assessment. The sample was comprised of 82 participants (52.4% female; 37.8% white; 42.7% low socioeconomic status) who were aged 22.61 years (SD = 1.50) at the time of the follow-up cognitive assessment. Prior to the follow-up cognitive assessment, they had completed an average of 6.24 (SD = 1.80) prior annual assessments over 6.24 years (SD = 2.08) as part of the parent longitudinal study in which C-reactive protein (CRP), depressive symptoms, and working memory were assessed repeatedly. First, using linear regression, we tested whether individuals exhibiting inflammation (CRP ≥3 mg/L) at multiple timepoints and a history of likely depression (Children's Depression Inventory ≥19) exhibited differentially worse executive functioning, episodic memory, or psychomotor speed. Second, using hierarchical linear modeling, we tested whether the combination of inflammation and likely past depression was associated with poorer working memory over time. Chronic inflammation was associated with worsening working memory over time, but no significant associations were observed in cross-sectional analyses. These preliminary data indicate that chronic inflammation may lead to progressive decline in working memory over time.

Initial development of tools to identify child abuse and neglect in pediatric primary care.

BACKGROUND: Child abuse and neglect (CAN) is prevalent, associated with long-term adversities, and often undetected. Primary care settings offer a unique opportunity to identify CAN and facilitate referrals, when warranted. Electronic health records (EHR) contain extensive information to support healthcare decisions, yet time constraints preclude most providers from thorough EHR reviews that could indicate CAN. Strategies that summarize EHR data to identify CAN and convey this to providers has potential to mitigate CAN-related sequelae. This study used expert review/consensus and Natural Language Processing (NLP) to develop and test a lexicon to characterize children who have experienced or are at risk for CAN and compared machine learning methods to the lexicon + NLP approach to determine the algorithm's performance for identifying CAN. METHODS: Study investigators identified 90 CAN terms and invited an interdisciplinary group of child abuse experts for review and validation. We then used NLP to develop pipelines to finalize the CAN lexicon. Data for pipeline development and refinement were drawn from a randomly selected sample of EHR from patients seen at pediatric primary care clinics within a U.S. academic health center. To explore a machine learning approach for CAN identification, we used Support Vector Machine algorithms. RESULTS: The investigator-generated list of 90 CAN terms were reviewed and validated by 25 invited experts, resulting in a final pool of 133 terms. NLP utilized a randomly selected sample of 14,393 clinical notes from 153 patients to test the lexicon, and .03% of notes were identified as CAN positive. CAN identification varied by clinical note type, with few differences found by provider type (physicians versus nurses, social workers, etc.). An evaluation of the final NLP pipelines indicated 93.8% positive CAN rate for the training set and 71.4% for the test set, with decreased precision attributed primarily to false positives. For the machine learning approach, SVM pipeline performance was 92% for CAN + and 100% for non-CAN, indicating higher sensitivity than specificity. CONCLUSIONS: The NLP algorithm's development and refinement suggest that innovative tools can identify youth at risk for CAN. The next key step is to refine the NLP algorithm to eventually funnel this information to care providers to guide clinical decision making.

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder.

Objective: Posttraumatic stress disorder (PTSD) is a chronic and disabling disorder, for which available pharmacotherapies have limited efficacy. The authors' previous proof-of-concept randomized controlled trial of single-dose intravenous ketamine infusion in individuals with PTSD showed significant and rapid PTSD symptom reduction 24 hours postinfusion. The present study is the first randomized controlled trial to test the efficacy and safety of repeated intravenous ketamine infusions for the treatment of chronic PTSD. Methods: Individuals with chronic PTSD (N=30) were randomly assigned (1:1) to receive six infusions of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) (psychoactive placebo control) over 2 consecutive weeks. Clinician-rated and self-report assessments were administered 24 hours after the first infusion and at weekly visits. The primary outcome measure was change in PTSD symptom severity, as assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), from baseline to 2 weeks (after completion of all infusions). Secondary outcome measures included the Impact of Event Scale-Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS), and side effect measures. Results: The ketamine group showed a significantly greater improvement in CAPS-5 and MADRS total scores than the midazolam group from baseline to week 2. At week 2, the mean CAPS-5 total score was 11.88 points (SE=3.96) lower in the ketamine group than in the midazolam group (d=1.13, 95% CI=0.36, 1.91). Sixty-seven percent of participants in the ketamine group were treatment responders, compared with 20% in the midazolam group. Among ketamine responders, the median time to loss of response was 27.5 days following the 2-week course of infusions. Ketamine infusions were well tolerated overall, without serious adverse events. Conclusions: This randomized controlled trial provides the first evidence of efficacy of repeated ketamine infusions in reducing symptom severity in individuals with chronic PTSD. Further studies are warranted to understand ketamine's full potential as a treatment for chronic PTSD.Reprinted from Am J Psychiatry 2021; 178:193-202, with permission from American Psychiatric Association Publishing. Copyright © 2021.

The Impact of Early and Recent Life Stress on Trajectories of Inflammatory Biomarkers in a Diverse Sample of Adolescents.

Elevated inflammatory activity is one possible pathway through which exposure to childhood adversity engenders risk for physical and psychiatric illnesses. Limited research has investigated the compounding effects of childhood and adolescent stress exposure on changes in circulating levels of inflammatory biomarkers. This study assessed whether childhood adversity interacted with chronic or acute stress during adolescence to affect the temporal trajectories of five inflammatory biomarkers across at least three blood draws in a diverse sample of adolescents (N = 134; observations = 462). Using multilevel modeling, the interaction of childhood adversity, time, and within-person variance of acute stressors significantly predicted trajectories of higher interleukin-10 levels, controlling for demographics, medication use, and body mass index. Adolescents with high levels of childhood adversity who were exposed to a higher frequency of acute stressors compared to their own average rate of stress exposure consistently had higher levels of IL-10 as they got older, but those with average and below frequency of acute stressors had decreasing trajectories of log IL-10 as they matured. The results demonstrate how events early in life shape biological responses to the adolescent environment. This study also highlights the importance of developmental timing on the body's enhanced reactivity to acute and sustained stressors following childhood adversity.

Stress-related reduction of hippocampal subfield volumes in major depressive disorder: A 7-Tesla study.

Background: Major depressive disorder (MDD) is a prevalent health problem with complex pathophysiology that is not clearly understood. Prior work has implicated the hippocampus in MDD, but how hippocampal subfields influence or are affected by MDD requires further characterization with high-resolution data. This will help ascertain the accuracy and reproducibility of previous subfield findings in depression as well as correlate subfield volumes with MDD symptom scores. The objective of this study was to assess volumetric differences in hippocampal subfields between MDD patients globally and healthy controls (HC) as well as between a subset of treatment-resistant depression (TRD) patients and HC using automatic segmentation of hippocampal subfields (ASHS) software and ultra-high field MRI. Methods: Thirty-five MDD patients and 28 HC underwent imaging using 7-Tesla MRI. ASHS software was applied to the imaging data to perform automated hippocampal segmentation and provide volumetrics for analysis. An exploratory analysis was also performed on associations between symptom scores for diagnostic testing and hippocampal subfield volumes. Results: Compared to HC, MDD and TRD patients showed reduced right-hemisphere CA2/3 subfield volume (p = 0.01, η 2 = 0.31 and p = 0.3, η 2 = 0.44, respectively). Additionally, negative associations were found between subfield volumes and life-stressor checklist scores, including left CA1 (p = 0.041, f 2 = 0.419), left CA4/DG (p = 0.010, f 2 = 0.584), right subiculum total (p = 0.038, f 2 = 0.354), left hippocampus total (p = 0.015, f 2 = 0.134), and right hippocampus total (p = 0.034, f 2 = 0.110). Caution should be exercised in interpreting these results due to the small sample size and low power. Conclusion: Determining biomarkers for MDD and TRD pathophysiology through segmentation on high-resolution MRI data and understanding the effects of stress on these regions can enable better assessment of biological response to treatment selection and may elucidate the underlying mechanisms of depression.

Protocol for project MIME: Motivation, inflammation, and Mood in Emerging Adults.

Background: Atypical inflammatory biology is gaining evidence as a risk factor for mood psychopathology; however, little work has attempted to integrate inflammation into extant psychosocial frameworks of risk. Recent work using secondary data analysis has investigated the possibility of an immunocognitive model of mood disorders, in which cognitive vulnerabilities (i.e., rumination on positive or negative affect) increase the effect that arousal-related characteristics (e.g., reward sensitivity) have on inflammatory biology in ways that may confer risk for depression and hypo/mania symptoms. Project MIME (Motivation, Inflammation, and Mood in Emerging Adults) was designed to test this model in the context of a novel, reward-salient stressor (the Anger Incentive Delay Task, AIDT). Methods: This NIMH-funded study will result in a dataset of approximately 100 college undergraduates from a large university in Pennsylvania, United States of America. Eligible participants are recruited from an online screener, have to be 18-22 years old, fluent in English, and successfully answer several items designed to test whether participants randomly answer questions on the screener. Eligible participants are invited to an in-person visit in which they completed the AIDT, blood draws pre- and 50 minutes post-AIDT, and self-report questionnaires. Participants also complete a set of online questionnaires two weeks after the in-person visit. Discussion: Consistent with calls from the NIH director, this study seeks to diversify the tools used in stress research by validating a novel reward-salient stressor (in contrast to the field's reliance on social stressors) with respect to affective and immunological stress reactivity. In addition to this methodological goal, Project MIME is the first study specifically designed to test the immunocognitive model of mood psychopathology. Given the integration of several malleable treatment targets (approach behavior, emotion regulation, inflammation) into this model, results from this study could inform comprehensive, flexible intervention strategies for mood disorder prevention and treatment.

Residence in High-Crime Neighborhoods Moderates the Association Between Interleukin 6 and Social and Nonsocial Reward Brain Responses.

BACKGROUND: Residence in high-crime neighborhoods, especially in childhood, is linked to mental health issues later. Detecting distinct neurobiological processes underlying the effects of this environmental stressor may be critical to identifying prevention and intervention targets. This study examined the relationships of levels of a circulating inflammatory protein with social and monetary reward-related brain function among adolescents who lived in high- versus low-crime neighborhoods during childhood. METHODS: A total of 70 participants (mean age = 16.3 years; 57% female) completed measures of inflammatory markers, depression history, and health and 2 functional magnetic resonance imaging tasks assessing responsivity to monetary and social rewards. Multivariate linear regression tested whether individuals with higher interleukin 6, an inflammatory cytokine, who also lived in neighborhoods with higher crime had distinct orbitofrontal cortex and nucleus accumbens activation to monetary reward and social acceptance. RESULTS: For adolescents who lived in neighborhoods with more crime, higher interleukin 6 was associated with higher nucleus accumbens responses to social acceptance. We did not detect significant moderating effects of neighborhood crime rates on the associations of interleukin 6 with orbitofrontal cortex responses to social acceptance or orbitofrontal cortex/nucleus accumbens activation during monetary reward anticipation or outcome. These results were obtained before and after adjusting for neighborhood income and other covariates. We did not detect significant moderating effects of neighborhood income. CONCLUSIONS: High-threat residence environment and specific demands of the social context in childhood may have shaped the effect of peripheral immune activation on reward-related neural function in adolescence. The prevailing view that inflammation-associated behaviors are characterized by blunted responsiveness to reward may be oversimplistic.

Sleep irregularity and nonsuicidal self-injurious urges and behaviors.

STUDY OBJECTIVES: The objectives of this study were to examine the relationships between sleep regularity and nonsuicidal self-injury (NSSI), including lifetime NSSI history and daily NSSI urges. METHODS: Undergraduate students (N = 119; 18-26 years), approximately half of whom endorsed a lifetime history of repetitive NSSI, completed a 10-day actigraphy and ecological momentary assessment (EMA) protocol. A Sleep Regularity Index was calculated for all participants using scored epoch by epoch data to capture rapid changes in sleep schedules. Participants responded to EMA prompts assessing NSSI urge severity and negative affect three times daily over the 10-day assessment period. RESULTS: Results indicate that individuals with a repetitive NSSI history were more likely to experience sleep irregularity than those without a history of NSSI. Findings also suggest that sleep irregularity was associated with more intense urges to engage in NSSI on a daily basis, even after accounting for average daily sleep duration, sleep timing, negative affect, and NSSI history. Neither sleep duration nor sleep timing was associated with NSSI history nor daily NSSI urge intensity. CONCLUSIONS: Findings suggest that sleep irregularity is linked with NSSI, including NSSI history and intensity of urges to engage in NSSI. The present study not only supports the growing evidence linking sleep disturbance with the risk for self-injury but also demonstrates this relationship using actigraphy and real-time assessments of NSSI urge severity. Findings highlight the importance of delineating the nuances in sleep irregularity that are proximally associated with NSSI risk and identifying targets for intervention.

Examining momentary associations between behavioral approach system indices and nonsuicidal self-injury urges.

BACKGROUND: The current study aimed to examine the concurrent and prospective relationships between the three hypothesized components of behavioral approach system (BAS) sensitivity: drive, reflecting the motivation to pursue one's desired goals; reward responsiveness, reflecting sensitivity to reward or reinforcement; and fun-seeking, reflecting the motivation for pursuing novel rewards in a spontaneous manner, and NSSI urge severity. METHODS: A sample of 64 undergraduates with a history of repetitive NSSI completed an ecological momentary assessment protocol. During this period of time, participants reported on the BAS-constructs of drive, reward responsiveness, and fun-seeking, as well as NSSI urge severity on a momentary basis at three random intervals each day for a period of ten-days. RESULTS: Drive and reward responsiveness, but not fun-seeking, were concurrently positively associated with NSSI urge severity. However, no associations between BAS facets and prospective NSSI urges were found. LIMITATIONS: This study was limited by its use of single items to assess the BAS-constructs of drive, reward responsiveness, and fun-seeking. CONCLUSIONS: Our findings indicate that feeling strongly impacted by rewards and having a strong sense of drive toward goal attainment may represent cognitive risk states that are associated with increased within-person NSSI risk. However, their lack of prospective prediction may suggest that these cognitive states are associated only on a momentary basis with NSSI urges and may not confer risk.

Applications of psychoneuroimmunology models of toxic stress in prevention and intervention efforts across early development.

Although evidence supporting psychoneuroimmunology (PNI) models of toxic stress have emerged over the past decade, the PNI field has struggled to integrate these important findings into real-world practical applications. There is great potential for these models to reduce the societal burden of childhood adversity by facilitating early detection and prevention with those children and adolescents at greatest risk for stress-related physical and psychological disorders. But further research is needed to validate and scale developmentally appropriate interventions with specific immune and endocrine mechanism-based targets that are developmentally sensitive. The allostatic load and additive PNI models of toxic stress exposure in youth are summarized. These models highlight the importance of integrating a standardized screening of environmental and interpersonal risk factors with stable and scalable cognitive and biological markers of risk. PNI models of toxic stress illustrate the need for intervention delivery as early as possible to prevent negative health outcomes in youth and comprehensive screening efforts would facilitate the deployment of community and family level interventions. This review discusses practical applications of toxic stress models that are currently under investigation, clarifies key obstacles, such as research gaps and scalability, and provides potential solutions, including cross-disciplinary partnerships.

Neuroimaging correlates and predictors of response to repeated-dose intravenous ketamine in PTSD: preliminary evidence.

Promising initial data indicate that the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine may be beneficial in post-traumatic stress disorder (PTSD). Here, we explore the neural correlates of ketamine-related changes in PTSD symptoms, using a rich battery of functional imaging data (two emotion-processing tasks and one task-free scan), collected from a subset of participants of a randomized clinical trial of repeated-dose intravenous ketamine vs midazolam (total N = 21). In a pre-registered analysis, we tested whether changes in an a priori set of imaging measures from a target neural circuit were predictive of improvement in PTSD symptoms, using leave-one-out cross-validated elastic-net regression models (regions of interest in the target circuit consisted of the dorsal and rostral anterior cingulate cortex, ventromedial prefrontal cortex, anterior hippocampus, anterior insula, and amygdala). Improvements in PTSD severity were associated with increased functional connectivity between the ventromedial prefrontal cortex (vmPFC) and amygdala during emotional face-viewing (change score retained in model with minimum predictive error in left-out subjects, standardized regression coefficient [ß] = 2.90). This effect was stronger in participants who received ketamine compared to midazolam (interaction ß = 0.86), and persisted following inclusion of concomitant change in depressive symptoms in the analysis model (ß = 0.69). Improvement following ketamine was also predicted by decreased dorsal anterior cingulate activity during emotional conflict regulation, and increased task-free connectivity between the vmPFC and anterior insula (ßs = -2.82, 0.60). Exploratory follow-up analysis via dynamic causal modelling revealed that whilst improvement in PTSD symptoms following either drug was associated with decreased excitatory modulation of amygdala→vmPFC connectivity during emotional face-viewing, increased top-down inhibition of the amygdala by the vmPFC was only observed in participants who improved under ketamine. Individuals with low prefrontal inhibition of amygdala responses to faces at baseline also showed greater improvements following ketamine treatment. These preliminary findings suggest that, specifically under ketamine, improvements in PTSD symptoms are accompanied by normalization of hypofrontal control over amygdala responses to social signals of threat.

Self-Critical and Self-Punishment Cognitions Differentiate Those With and Without a History of Nonsuicidal Self-Injury: An Ecological Momentary Assessment Study.

The aim of this study was to examine trait, state, and temporal instability measures of self-critical and self-punishment cognitions to evaluate their respective roles in nonsuicidal self-injury (NSSI). Participants were university students with a history of NSSI (n = 64) and those with no history of NSSI (n = 59). At baseline, participants completed measures assessing history of NSSI behavior, as well as trait measures of self-criticism and self-punishment. After completion of baseline procedures, participants subsequently participated in a 10-day ecological momentary assessment protocol in which self-critical and self-punishment cognitions were assessed in real time three times daily. Employing bivariate and multivariate frameworks, our results demonstrate that both trait and state levels of self-critical and self-punishment cognitions robustly differentiate between young adults with and without a lifetime history of NSSI. The present results also confirm that the temporal instability of these cognitive states also meaningfully differentiate between groups, such that those who exhibit greater fluctuations in these cognitive states are more likely to have a history of NSSI. The current findings suggest that trait, state, and temporal instability of negative self-focused cognitions may be vulnerability factors for engagement in NSSI.

Emotional response inhibition to self-harm stimuli interacts with momentary negative affect to predict nonsuicidal self-injury urges.

The current study investigated whether impaired emotional response inhibition to self-harm stimuli is a risk factor for real-time nonsuicidal self-injury (NSSI) urges. Participants were 60 university students with a history of repetitive NSSI. At baseline, participants completed an emotional stop-signal task assessing response inhibition to self-harm stimuli. Participants subsequently completed an ecological momentary assessment protocol in which they reported negative affect, urgency, and NSSI urge intensity three times daily over a ten-day period. Impaired emotional response inhibition to self-harm stimuli did not evidence a main effect on the strength of momentary NSSI urges. However, emotional response inhibition to self-harm images interacted with momentary negative affect to predict the strength of real-time NSSI urges, after adjusting for emotional response inhibition to neutral images. Our findings suggest that emotional response inhibition deficits specifically to self-harm stimuli may pose vulnerability for increased NSSI urge intensity during real-time, state-level negative affect.

Real-time monitoring of the associations between self-critical and self-punishment cognitions and nonsuicidal self-injury.

The Defective Self Model of nonsuicidal self-injury (NSSI) proposes that some people engage in NSSI to punish themselves and/or to respond to self-critical cognitions. Although there is a growing body of research to support this theory, there has been a lack of ecologically valid approaches employed to critically examine its tenets. The current study aimed to fill this gap in the literature. A sample of 64 undergraduates with a history of repetitive NSSI were recruited and completed an ecological momentary assessment (EMA) protocol. At baseline, participants completed trait measures of self-criticism and self-punishment cognitions. Over the EMA period, participants reported their experience of self-critical and self-punitive cognitions, and NSSI urge intensity three times daily. Our between-persons level findings suggest that trait and aggregated state self-punishment, but not self-critical cognitions, predict NSSI urges experienced over the EMA period. Our findings additionally provide evidence that both momentary self-critical and self-punishment cognitions are concomitantly and prospectively associated with NSSI urge intensity as measured in real-time and modeled at a within-persons level. However, after adjusting for concurrent NSSI urge intensity in prospective models, these within-persons level findings do not hold. Nevertheless, our findings provide greater support for the Defective Self Model of NSSI.

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder.

OBJECTIVE: Posttraumatic stress disorder (PTSD) is a chronic and disabling disorder, for which available pharmacotherapies have limited efficacy. The authors' previous proof-of-concept randomized controlled trial of single-dose intravenous ketamine infusion in individuals with PTSD showed significant and rapid PTSD symptom reduction 24 hours postinfusion. The present study is the first randomized controlled trial to test the efficacy and safety of repeated intravenous ketamine infusions for the treatment of chronic PTSD. METHODS: Individuals with chronic PTSD (N=30) were randomly assigned (1:1) to receive six infusions of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) (psychoactive placebo control) over 2 consecutive weeks. Clinician-rated and self-report assessments were administered 24 hours after the first infusion and at weekly visits. The primary outcome measure was change in PTSD symptom severity, as assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), from baseline to 2 weeks (after completion of all infusions). Secondary outcome measures included the Impact of Event Scale-Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS), and side effect measures. RESULTS: The ketamine group showed a significantly greater improvement in CAPS-5 and MADRS total scores than the midazolam group from baseline to week 2. At week 2, the mean CAPS-5 total score was 11.88 points (SE=3.96) lower in the ketamine group than in the midazolam group (d=1.13, 95% CI=0.36, 1.91). Sixty-seven percent of participants in the ketamine group were treatment responders, compared with 20% in the midazolam group. Among ketamine responders, the median time to loss of response was 27.5 days following the 2-week course of infusions. Ketamine infusions were well tolerated overall, without serious adverse events. CONCLUSIONS: This randomized controlled trial provides the first evidence of efficacy of repeated ketamine infusions in reducing symptom severity in individuals with chronic PTSD. Further studies are warranted to understand ketamine's full potential as a treatment for chronic PTSD.

Insulin receptor substrate in brain-enriched exosomes in subjects with major depression: on the path of creation of biosignatures of central insulin resistance.

Insulin signaling is critical for neuroplasticity, cerebral metabolism as well as for systemic energy metabolism. In rodent studies, impaired brain insulin signaling with resultant insulin resistance (IR) modulates synaptic plasticity and the corresponding behavioral functions. Despite discoveries of central actions of insulin, in vivo molecular mechanisms of brain IR until recently have proven difficult to study in the human brain. In the current study, we leveraged recent technological advances in molecular biology and herein report an increased number of exosomes enriched for L1CAM, a marker predominantly expressed in the brain, in subjects with major depressive disorder (MDD) as compared with age- and sex-matched healthy controls (HC). We also report increased concentration of the insulin receptor substrate-1 (IRS-1) in L1CAM+ exosomes in subjects with MDD as compared with age- and sex-matched HC. We found a relationship between expression of IRS-1 in L1CAM+ exosomes and systemic IR as assessed by homeostatic model assessment of IR in HC, but not in subjects with MDD. The increased IRS-1 levels in L1CAM+ exosomes were greater in subjects with MDD and were associated with suicidality and anhedonia. Finally, our data suggested sex differences in serine-312 phosphorylation of IRS-1 in L1CAM+ exosomes in subjects with MDD. These findings provide a starting point for creating mechanistic framework of brain IR in further development of personalized medicine strategies to effectively treat MDD.

How handling extreme C-reactive protein (CRP) values and regularization influences CRP and depression criteria associations in network analyses.

Increasingly, it has been recognized that analysis at the symptom, rather than diagnostic, level will drive progress in the field of immunopsychiatry. Network analysis offers a useful tool in this pursuit with the ability to identify associations between immune markers and individual symptoms, independent of all other variables modeled. However, investigation into how methodological decisions (i.e., including vs. excluding participants with C-reactive protein (CRP) >10 mg/L, regularized vs. nonregularized networks) influence results is necessary to establish best practices for the use of network analysis in immunopsychiatry. In a sample of 3,464 adult participants from the 2015-2016 National Health and Nutrition Examination Survey dataset, this study found consistent support for associations between CRP and fatigue and changes in appetite and some support for additional CRP-criterion associations. Methodologically, results consistently demonstrated that including individuals with CRP >10 mg/L and estimating nonregularized networks provided better estimates of these associations. Thus, we recommend considering the use of nonregularized networks in immunopsychiatry and inclusion of cases with CRP values >10 mg/L when testing the association between CRP and depression criteria, unless contraindicated by the research question being tested. Additionally, results most consistently suggest that CRP is uniquely related to fatigue and changes in appetite, supporting their inclusion in an immunometabolic phenotype of depression. Finally, these associations suggest that fatigue and changes in appetite might be particularly receptive to anti-inflammatory treatments. However, future research with more nuanced measures is necessary to parse out whether appetite increases or decreases drive this association. Further, longitudinal research is an important next step to test how these relationships manifest over time.

The role of reward sensitivity and childhood maltreatment in predicting nonsuicidal self-injury.

OBJECTIVE: Findings from prior research on reward sensitivity in nonsuicidal self-injury (NSSI) have been mixed. Childhood maltreatment is an independent risk factor for NSSI and for hyposensitivity to rewards. This study aimed to disentangle the role of reward sensitivity as a predictor of NSSI for those with an elevated severity of childhood maltreatment. METHOD: In a diverse undergraduate sample (N = 586), trait reward sensitivity (i.e., behavioral approach system subscales) and the severity of maltreatment were assessed as predictors of a lifetime history of NSSI. In a subset of this sample (n = 51), predictors of NSSI urge intensity were measured using ecological momentary assessment. RESULTS: Individuals with elevated maltreatment who reported less positive responsiveness to rewards were more likely to have a lifetime history of NSSI. Those with elevated maltreatment who reported a lower likelihood to approach rewards experienced more intense NSSI urges across the ten-day observation period. However, those with elevated maltreatment who reported a greater likelihood to approach rewards experienced less intense NSSI urges. CONCLUSIONS: The role of reward sensitivity as a cognitive risk factor for NSSI varies depending on childhood maltreatment history. Findings indicate that, for those with elevated maltreatment, hypersensitivity to approaching rewards may decrease risk for NSSI urges.

Bidirectional Associations Between Inflammatory Biomarkers and Depressive Symptoms in Adolescents: Potential Causal Relationships.

There are inconsistent findings in the literature about the directionality and magnitude of the association between inflammation and depressive symptoms. This analysis separates predictors into between-person and within-person components to gain greater clarity about this relationship. Blood samples were collected and depressive symptoms assessed in 140 adolescents (54% female, 59% Black, Mage = 16.1 years) with at least three blood draws and a total of 394 follow-up observations. Multi-level modeling indicated that the within-person effect of tumor necrosis factor alpha (TNF-α) predicted change in total depressive symptoms, suggesting a potential causal relationship. There were no significant within-person effects of total depressive symptoms on change in biomarkers. Exploratory analyses examined associations between inflammatory biomarkers and subsets of depressive symptoms. These findings inform modeling decisions that may explain inconsistencies in the extant literature as well as suggest potential causal relationships between certain proteins with significant within-person effects on depressive symptoms, and vice-versa.