Uptake of extracellular vesicles into immune cells is enhanced by the protein corona.

The influence of a protein corona on the uptake of nanoparticles in cells has been demonstrated in various publications over the last years. Extracellular vesicles (EVs), can be seen as natural nanoparticles. However, EVs are produced under different cell culture conditions and little is known about the protein corona forming on EVs and its influence on their uptake by target cells. Here, we use a proteomic approach in order to analyze the protein composition of the EVs themselves and the protein composition of a human blood plasma protein corona around EVs. Moreover, we analyze the influence of the protein corona on EV uptake into human monocytes and compare it with the influence on the uptake of engineered liposomes. We show that the presence of a protein corona increases the uptake of EVs in human monocytes. While for liposomes this seems to be triggered by the presence of immunoglobulins in the protein corona, for EVs blocking the Fc receptors on monocytes did not show an influence of uptake. Therefore, other mechanisms of docking to the cell membrane and uptake are most like involved, demonstrating a clear difference between EVs and liposomes as technically produced nanocarriers.

Developing a personalized self-care curriculum for graduate students in the health sciences.

The purpose of this study was to evaluate the Pitt Personal Wellness Program, three 1-hour workshops that were integrated into the first-semester curriculum of five health sciences graduate programs. The workshops were designed as a personalized education approach to promote self-care and well-being. Of the 156 graduate students who participated in the Pitt Personal Wellness Program, 99 (65%) completed online questionnaires regarding stress and coping at three time points across a 14 week period: before the program, and after the second and third workshops. Graduate students reported significant decreases in perceived stress and number of stressful situations across the three time points. Students who reported a previous history of mental health counseling demonstrated steeper declines in perceived stress across Times 1 and 2, and reported significantly higher use of coping strategies across the three time points. Racially minoritized students and those reporting more financial struggles also reported significant declines in stress and number of stressors across Times 1 and 2. The Pitt Personal Wellness Program was acceptable to graduate students and a promising program for further dissemination and study.

Assessing Aspects of Social Relationships in Youth Across Middle Childhood and Adolescence: The NIH Toolbox Pediatric Social Relationship Scales.

OBJECTIVE: Social relationships are a critical context for children's socioemotional development and their quality is closely linked with concurrent and future physical and emotional wellbeing. However, brief self-report measures of social relationship quality that translate across middle childhood, adolescence, and adulthood are lacking, limiting the ability to assess the impact of social relationships on health outcomes over time. To address this gap, this article describes the development and testing of the National Institutes of Health (NIH) Toolbox Pediatric Social Relationship Scales, which were developed in parallel with the previously-reported Adult Social Relationship Scales. METHODS: Item sets were selected from the NIH Toolbox adult self-report item banks in the domains of social support, companionship, and social distress, and adapted for use in preadolescent (ages 8-11 years) and adolescent (ages 12-18 years) cohorts. Items were tested across a U.S. community sample of 1,038 youth ages 8-18 years. Classical test and item response theory approaches were used to identify items for inclusion in brief unidimensional scales. Concurrent validity was assessed by comparing resultant scales to established pediatric social relationship instruments. RESULTS: Internal reliability and concurrent validity were established for five unique scales, with 5-7 items each: Emotional Support, Friendship, Loneliness, Perceived Rejection, and Perceived Hostility. CONCLUSIONS: These brief scales represent developmentally appropriate and valid instruments for assessing the quality of youth social relationships across childhood and adolescence. In conjunction with previously published adult scales, they provide an opportunity for prospective assessment of social relationships across the developmental spectrum.

Neutralizing Antibody Evasion and Transduction with Purified Extracellular Vesicle-Enveloped Adeno-Associated Virus Vectors.

Adeno-associated virus (AAV) is classified as a nonenveloped DNA virus. However, several years ago, we discovered that in media of packaging cells producing recombinant AAV vectors, AAV capsids can associate with the interior and surface of extracellular vesicles (EVs), sometimes referred to as exosomes. Since then, we and others have demonstrated that exosome-enveloped AAV, exo-AAV, can enhance transduction in vivo as well as evade neutralizing antibodies. While promising, these data were generated with differential centrifugation to pellet the exo-AAV. This method results in a heterogeneous mixture of exo-AAV, coprecipitating proteins, as well as free AAV capsids. To define the properties of exo-AAV more accurately, in this study, we used a density gradient method to purify exo-AAV. We next performed head-to-head comparisons of standard AAV1, differential centrifuged exo-AAV1, and gradient purified exo-AAV1 for antibody evasion and transgene expression in the murine brain. We found purified exo-AAV1 to be more resistant to neutralizing antibodies than the other AAV preparations. Direct intracranial injection of purified exo-AAV1 into mice resulted in robust transduction, which transduced a larger area of brain than standard AAV1. We also identified the recently described membrane-associated accessory protein by mass spectrometry of purified exo-AAV1 preparations. Finally, we used a scalable method, size-exclusion chromatography to isolate exo-AAV1, and demonstrated functional transduction in cultured cells and increased antibody resistance. Together, these data suggest that higher purity exo-AAV will have beneficial characteristics for gene delivery and also may lead to mechanistic insights into the incorporation of AAV into EVs.

Family-Based Interpersonal Psychotherapy: An Intervention for Preadolescent Depression.

Family-based interpersonal psychotherapy (FB-IPT) is an evidence-based psychosocial intervention for depression in preadolescents (ages 8-12 years). Adapted from interpersonal psychotherapy for adolescents with depression and modified for younger children, this therapy includes structured dyadic sessions with preadolescents and their parents, guidance for parents in supporting their children and decreasing negative parent-child interactions, and a focus on preadolescents' comorbid anxiety and peer relationships. This article reviews the conceptual foundations and risk factors related to preadolescent depression and the rationale for focusing on improving preadolescents' interpersonal relationships to decrease depressive symptoms and risk for depression during adolescence. The structure and goals for the initial, middle, and termination phases of FB-IPT are described, as well as the specific communication and problem-solving strategies presented to preadolescents and parents. Last, research on the efficacy of FB-IPT is summarized, as are future directions for implementing this promising psychosocial intervention for preadolescent depression in community settings.

Immunomodulation in Oncolytic Measles Virotherapy.

With the recognition of oncolytic virotherapy as an immunotherapy, the distinct interactions between oncolytic agents and the immune system have come into focus. The role of the immune system in oncolytic virotherapy is somewhat ambiguous: While preexisting or arising immunity directed against viral antigens may preclude efficient viral replication and spread, immunity directed against tumor antigens is considered essential for long-term treatment success. Aside from the antiviral and antitumor immune status of the patient, the specific immunological microenvironment in a given tumor adds an additional layer of complexity.In this review we focus on the case of measles virus, which has long been known for its multifaceted interplay with the immune system. The high prevalence of measles-neutralizing antibodies in the general population may pose additional challenges. The oncolytic measles virus vector platform offers manifold opportunities for tumor-targeted immunomodulation. This review provides a survey of immunomodulation in the context of measles virotherapy including strategies to suppress or circumvent antiviral immunity as well as enhance antitumor immunity that have been pursued in preclinical and clinical studies. Understanding and selective manipulation of the intricate balance between antiviral and antitumor immunity will be crucial to develop the full potential of oncolytic virotherapy.

Engineered anti-CRISPR proteins for optogenetic control of CRISPR-Cas9.

Anti-CRISPR proteins are powerful tools for CRISPR-Cas9 regulation; the ability to precisely modulate their activity could facilitate spatiotemporally confined genome perturbations and uncover fundamental aspects of CRISPR biology. We engineered optogenetic anti-CRISPR variants comprising hybrids of AcrIIA4, a potent Streptococcus pyogenes Cas9 inhibitor, and the LOV2 photosensor from Avena sativa. Coexpression of these proteins with CRISPR-Cas9 effectors enabled light-mediated genome and epigenome editing, and revealed rapid Cas9 genome targeting in human cells.

Blood pressure recovery to social stress in parentally bereaved and non-bereaved youths.

OBJECTIVE: To examine differences in blood pressure response and recovery in a sample of bereaved and non-bereaved youths during an acute stress task conducted 5 years after time of parental death. METHODS: One-hundred and ninety-two (n = 192) bereaved and non-bereaved offspring (ages 11-29) participated in an adaptation of the Trier Social Stress Task (TSST) 5-years after the time of parental death. Blood pressure measurements were collected before, during, and after the laboratory stress protocol. Mixed models for repeated measures were used to analyze the effects of bereavement status and course of psychiatric disorder in the 5-year period after parental death in both offspring and caregivers on blood pressure response; linear regression was used to examine these associations with blood pressure recovery. RESULTS: Although there were no differences across groups in diastolic (DBP) or systolic blood pressure (SBP) response to stress, bereaved offspring demonstrated less SBP recovery to the TSST as compared to non-bereaved offspring. A significant interaction between bereavement status and race, and a marginally significant interaction between bereavement status and sex indicated poor SBP recovery for parentally bereaved racial/ethnic minority offspring as compared to parentally bereaved Caucasian offspring, and for parentally bereaved males compared to parentally bereaved females. CONCLUSIONS: Parentally bereaved youths demonstrate blood pressure response to social stress tasks similar to that of non-bereaved youths, but parentally bereaved ethnic/racial minority youths and parentally bereaved males evidence a less complete recovery from the effects of stress. The health consequences of poor blood pressure recovery in bereaved youths are discussed.

A randomized, comparative pilot trial of family-based interpersonal psychotherapy for reducing psychosocial symptoms, disordered-eating, and excess weight gain in at-risk preadolescents with loss-of-control-eating.

OBJECTIVE: Preadolescent loss-of-control-eating (LOC-eating) is a risk factor for excess weight gain and binge-eating-disorder. We evaluated feasibility and acceptability of a preventive family-based interpersonal psychotherapy (FB-IPT) program. FB-IPT was compared to family-based health education (FB-HE) to evaluate changes in children's psychosocial functioning, LOC-eating, and body mass. METHOD: A randomized, controlled pilot trial was conducted with 29 children, 8 to 13 years who had overweight/obesity and LOC-eating. Youth-parent dyads were randomized to 12-week FB-IPT (n = 15) or FB-HE (n = 14) and evaluated at post-treatment, six-months, and one-year. Changes in child psychosocial functioning, LOC-eating, BMI, and adiposity by dual-energy-X-ray-absorptiometry were assessed. Missing follow-up data were multiply imputed. RESULTS: FB-IPT feasibility and acceptability were indicated by good attendance (83%) and perceived benefits to social interactions and eating. Follow-up assessments were completed by 73% FB-IPT and 86% FB-HE at post-treatment, 60% and 64% at six-months, and 47% and 57% at one-year. At post-treatment, children in FB-IPT reported greater decreases in depression (95% CI -7.23, -2.01, Cohen's d = 1.23) and anxiety (95% CI -6.08, -0.70, Cohen's d = .79) and less odds of LOC-eating (95% CI -3.93, -0.03, Cohen's d = .38) than FB-HE. At six-months, children in FB-IPT had greater reductions in disordered-eating attitudes (95% CI -0.72, -0.05, Cohen's d = .66) and at one-year, tended to have greater decreases in depressive symptoms (95% CI -8.82, 0.44, Cohen's d = .69) than FB-HE. There was no difference in BMI gain between the groups. DISCUSSION: Family-based approaches that address interpersonal and emotional underpinnings of LOC-eating in preadolescents with overweight/obesity show preliminary promise, particularly for reducing internalizing symptoms. Whether observed psychological benefits translate into sustained prevention of disordered-eating or excess weight gain requires further study.

Family-based interpersonal psychotherapy for depressed preadolescents: examining efficacy and potential treatment mechanisms.

OBJECTIVE: To conduct a randomized controlled trial to evaluate the preliminary efficacy of family-based interpersonal psychotherapy (FB-IPT) for treating depression in preadolescents (aged 7-12 years) as compared to child-centered therapy (CCT), a supportive and nondirective treatment that closely approximates the standard of care for pediatric depression in community mental health. METHOD: Preadolescents with depression (N = 42) were randomly assigned FB-IPT or CCT. Pre- and posttreatment assessments included clinician-administered measures of depression, parent- and child-reported depression and anxiety symptoms, and parent-child conflict and interpersonal impairment with peers. RESULTS: Preadolescents receiving FB-IPT had higher rates of remission (66.0% versus 31%), a greater decrease in depressive symptoms from pre- to posttreatment, and lower depressive symptoms at posttreatment (R(2) = 0.35, ΔR(2) = 0.22; B = -8.15, SE = 2.61, t[37] = -3.13, p = .002, F(2) = 0.28) than did preadolescents with depression receiving CCT. Furthermore, preadolescents in the FB-IPT condition reported significant reductions in anxiety and interpersonal impairment compared with preadolescents in the CCT condition. Changes in social and peer impairment from pre- to posttreatment were associated with preadolescents' posttreatment depressive symptoms. There was a significant indirect effect for decreased social impairment accounting for the association between the FB-IPT and preadolescents' posttreatment depressive symptoms. CONCLUSION: Findings indicate FB-IPT is an effective treatment for preadolescent depression and support further investigation of interpersonal mechanisms by which FB-IPT may reduce preadolescent depression. Clinical trial registration information-Phase II Study of Family Based Interpersonal Psychotherapy (FB-IPT) for Depressed Preadolescents; http://clinicaltrials.gov; NCT02054312.

Social problem solving among depressed adolescents is enhanced by structured psychotherapies.

OBJECTIVE: Changes in adolescent interpersonal behavior before and after an acute course of psychotherapy were investigated as outcomes and mediators of remission status in a previously described treatment study of depressed adolescents. Maternal depressive symptoms were examined as moderators of the association between psychotherapy condition and changes in adolescents' interpersonal behavior. METHOD: Adolescents (n = 63, mean age = 15.6 years, 77.8% female, 84.1% White) engaged in videotaped interactions with their mothers before randomization to cognitive behavior therapy (CBT), systemic behavior family therapy (SBFT), or nondirective supportive therapy (NST) and after 12-16 weeks of treatment. Adolescent involvement, problem solving, and dyadic conflict were examined. RESULTS: Improvements in adolescent problem solving were significantly associated with CBT and SBFT. Maternal depressive symptoms moderated the effect of CBT, but not SBFT, on adolescents' problem solving; adolescents experienced increases in problem solving only when their mothers had low or moderate levels of depressive symptoms. Improvements in adolescents' problem solving were associated with higher rates of remission across treatment conditions, but there were no significant indirect effects of SBFT on remission status through problem solving. Exploratory analyses revealed a significant indirect effect of CBT on remission status through changes in adolescent problem solving, but only when maternal depressive symptoms at study entry were low. CONCLUSIONS: Findings provide preliminary support for problem solving as an active treatment component of structured psychotherapies for depressed adolescents and suggest one pathway by which maternal depression may disrupt treatment efficacy for depressed adolescents treated with CBT.

A prospective study of parentally bereaved youth, caregiver depression, and body mass index.

OBJECTIVE: To examine the relationship between body mass index (BMI) in bereaved youth and nonbereaved controls 5 years after a parent's death. The study was conducted from August 9, 2002, through December 31, 2013. DESIGN: A prospective, longitudinal, controlled study of the effects of sudden parental death on youth. SETTING: Bereaved families were recruited through coroner records and by advertisement. Nonbereaved families were recruited using random-digit dialing and by advertisement. PARTICIPANTS: 123 parentally bereaved offspring were compared with 122 nonbereaved control offspring, all of whom were aged 11-25 years at the 5-year assessment. MAIN EXPOSURE: Bereavement status, type of parental death (accident, suicide, or sudden natural death), and history of depression in caregivers prior to parental death. OUTCOME MEASURES: BMI categories (normal, overweight, and obese), according to International Obesity Task Force guidelines for adults and Centers for Disease Control and Prevention guidelines for children, and DSM-IV psychiatric disorder in offspring and caregivers before and after time of parental death. RESULTS: Bereaved offspring were more likely to have a BMI in the obese range compared to nonbereaved controls (χ2(2) = 7.13, P < .01). There were no differences in BMI category by death type among bereaved offspring. Caregiver history of depression was a significant correlate of offspring obesity in nonbereaved youth but had a protective effect on the BMI of bereaved youth. CONCLUSIONS: Bereaved youth were more likely to be obese than nonbereaved youth 5 years after parental death, and caregiver history of depression was associated with increased risk for obesity in nonbereaved youth only. Future studies are necessary to identify mechanisms that increase risk for obesity in parentally bereaved youth.

A pilot study of yoga as self-care for arthritis in minority communities.

BACKGROUND: While arthritis is the most common cause of disability, non-Hispanic blacks and Hispanics experience worse arthritis impact despite having the same or lower prevalence of arthritis compared to non-Hispanic whites. People with arthritis who exercise regularly have less pain, more energy, and improved sleep, yet arthritis is one of the most common reasons for limiting physical activity. Mind-body interventions, such as yoga, that teach stress management along with physical activity may be well suited for investigation in both osteoarthritis and rheumatoid arthritis. Yoga users are predominantly white, female, and college educated. There are few studies that examine yoga in minority populations; none address arthritis. This paper presents a study protocol examining the feasibility and acceptability of providing yoga to an urban, minority population with arthritis. METHODS/DESIGN: In this ongoing pilot study, a convenience sample of 20 minority adults diagnosed with either osteoarthritis or rheumatoid arthritis undergo an 8-week program of yoga classes. It is believed that by attending yoga classes designed for patients with arthritis, with racially concordant instructors; acceptability of yoga as an adjunct to standard arthritis treatment and self-care will be enhanced. Self-care is defined as adopting behaviors that improve physical and mental well-being. This concept is quantified through collecting patient-reported outcome measures related to spiritual growth, health responsibility, interpersonal relations, and stress management. Additional measures collected during this study include: physical function, anxiety/depression, fatigue, sleep disturbance, social roles, and pain; as well as baseline demographic and clinical data. Field notes, quantitative and qualitative data regarding feasibility and acceptability are also collected. Acceptability is determined by response/retention rates, positive qualitative data, and continuing yoga practice after three months. DISCUSSION: There are a number of challenges in recruiting and retaining participants from a community clinic serving minority populations. Adopting behaviors that improve well-being and quality of life include those that integrate mental health (mind) and physical health (body). Few studies have examined offering integrative modalities to this population. This pilot was undertaken to quantify measures of feasibility and acceptability that will be useful when evaluating future plans for expanding the study of yoga in urban, minority populations with arthritis. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01617421.

Cortisol response to social stress in parentally bereaved youth.

BACKGROUND: Parental bereavement is associated with increased risk for psychiatric illness and functional impairment in youth. Dysregulated hypothalamic-pituitary-adrenal (HPA) axis functioning may be one pathway through which bereaved children experience increased risk for poor outcomes. However, few studies have prospectively examined the association between parental bereavement and cortisol response while accounting for psychiatric disorders in both youth and their caregivers. METHODS: One-hundred and eighty-one bereaved and nonbereaved offspring and their caregivers were assessed at multiple time points over a 5-year period after parental death. Offspring participated in an adaptation of the Trier Social Stress Task (TSST), and salivary cortisol samples were collected before and after exposure to social stressors. Mixed models for repeated measures were used to analyze the effects of bereavement status, psychiatric disorder in both offspring and caregiver, and demographic indices on trajectories of cortisol response. RESULTS: After controlling for demographic variables and offspring depression, bereaved offspring demonstrated significantly different trajectories of cortisol response compared with nonbereaved offspring, characterized by higher total cortisol output and an absence of cortisol reactivity to acute social stress. Within the bereaved group, offspring of parents who died by sudden natural death demonstrated significant cortisol reactivity to social stress compared with offspring whose parents died by suicide, who demonstrated more blunted trajectory of cortisol response. CONCLUSIONS: Parentally bereaved youth demonstrate higher cortisol output than nonbereaved youth but are less able to mount an acute response in the face of social stressors.

Anhedonia predicts poorer recovery among youth with selective serotonin reuptake inhibitor treatment-resistant depression.

OBJECTIVE: To identify symptom dimensions of depression that predict recovery among selective serotonin reuptake inhibitor (SSRI) treatment-resistant adolescents undergoing second-step treatment. METHOD: The Treatment of Resistant Depression in Adolescents (TORDIA) trial included 334 SSRI treatment-resistant youth randomized to a medication switch, or a medication switch plus CBT. This study examined five established symptom dimensions (Child Depression Rating Scale-Revised) at baseline as they predicted recovery over 24 weeks of acute and continuation treatment. The two indices of recovery that were evaluated were time to remission and number of depression-free days. RESULTS: Multivariate analyses examining all five depression symptom dimensions simultaneously indicated that anhedonia was the only dimension to predict a longer time to remission, and also the only dimension to predict fewer depression-free days. In addition, when anhedonia and CDRS-total score were evaluated simultaneously, anhedonia continued to uniquely predict longer time to remission and fewer depression-free days. CONCLUSIONS: Anhedonia may represent an important negative prognostic indicator among treatment-resistant depressed adolescents. Further research is needed to elucidate neurobehavioral underpinnings of anhedonia, and to test treatments that target anhedonia in the context of overall treatment of depression.

Suicidality and depression disparities between sexual minority and heterosexual youth: a meta-analytic review.

PURPOSE: To examine disparities between sexual minority youth (SMY) and heterosexual youth in rates of suicidality and depression symptoms. METHODS: Separate meta-analyses were conducted to examine suicidality and depression disparities. Studies were included if the average age of the participants was <18 years, and if suicidality or depression symptoms were compared across SMY and heterosexual youth. RESULTS: SMY reported significantly higher rates of suicidality (odds ratio [OR] = 2.92) and depression symptoms (standardized mean difference, d = .33) as compared with the heterosexual youth. Disparities increased with the increase in the severity of suicidality (ideation [OR = 1.96], intent/plans [OR = 2.20], suicide attempts [OR = 3.18], suicide attempts requiring medical attention [OR = 4.17]). Effects did not vary across gender, recruitment source, and sexual orientation definition. CONCLUSIONS: Disparities in suicidality and depression may be influenced by negative experiences including discrimination and victimization. Clinicians should assess sexual orientation, analyze psychosocial histories to identify associated risk factors, and promote prevention and intervention opportunities for SMY and their families.

Inferring functional modules of protein families with probabilistic topic models.

BACKGROUND: Genome and metagenome studies have identified thousands of protein families whose functions are poorly understood and for which techniques for functional characterization provide only partial information. For such proteins, the genome context can give further information about their functional context. RESULTS: We describe a Bayesian method, based on a probabilistic topic model, which directly identifies functional modules of protein families. The method explores the co-occurrence patterns of protein families across a collection of sequence samples to infer a probabilistic model of arbitrarily-sized functional modules. CONCLUSIONS: We show that our method identifies protein modules - some of which correspond to well-known biological processes - that are tightly interconnected with known functional interactions and are different from the interactions identified by pairwise co-occurrence. The modules are not specific to any given organism and may combine different realizations of a protein complex or pathway within different taxa.

Depressive symptoms and subclinical markers of cardiovascular disease in adolescents.

PURPOSE: To examine the association between depressive symptoms and subclinical markers of cardiovascular disease (CVD), specifically arterial stiffness, as indexed by pulse wave velocity (PWV), and carotid artery intima media thickening (IMT), in a sample of healthy adolescents, and to explore adolescent hostility as a potential moderator of depression on subclinical markers of CVD. METHODS: One hundred fifty-seven (n = 157) black and white adolescents between the ages of 16-21 completed a follow-up study of psychosocial stress and cardiovascular risk factors that included measures of PWV and carotid IMT. Psychosocial measures included the Center for Epidemiologic Studies Depression Scale (divided into tertiles), and the Cook-Medley Hostility Inventory subscales. Linear regression models controlled for sociodemographic variables, health behaviors, blood pressure, body mass index, and heart rate. RESULTS: Results show that more severe depressive symptoms were associated with higher levels of PWV (B = .17, R(2) = .30, ΔR(2) = .03, confidence interval = 2.2-47.0, p = .03) but not with higher IMT. Adolescent depression remained a significant predictor of PWV when controlling for adolescent hostility; hostility did not moderate the relationship between adolescent depression and PWV. CONCLUSION: Depression may be important in the development of arterial stiffness in adolescence. Further research is needed to delineate the relationship in adolescence and young adulthood between depressive symptoms and the pathogenesis of CVD.

Maternal depression, paternal psychopathology, and toddlers' behavior problems.

This article examined the effects of maternal depression during the postpartum period (Time 1) on the later behavior problems of toddlers (Time 3) and tested if this relationship was moderated by paternal psychopathology during toddlers' lives and/or mediated by maternal parenting behavior observed during mother-child interaction (Time 2). Of the 101 mothers who participated in this longitudinal study with their toddlers, 51 had never experienced an episode of Major Depressive Disorder (MDD) and 50 had experienced an episode of MDD during the first 18 months of their toddlers' lives. Maternal depression at Time 1 was significantly associated with toddlers' externalizing and internalizing behavior problems only when paternal psychopathology was present. As predicted, maternal negativity at Time 2 was found to mediate the relationship between maternal depression at Time 1 and toddlers' externalizing behavior problems at Time 3.