Developmental aspects of mood disorders

Dispositional Mindfulness Profiles in Adolescents and their Associations with Psychological Functioning and Hypothalamic-Pituitary-Adrenal Axis Hormones

Adolescence is often accompanied by an increase in stress and depression. Although there is considerable consensus about the benefits of mindfulness-based interventions to reduce these problems, the results for the role of dispositional mindfulness facets have been mixed. Recent studies have contributed to clarifying this role by identifying subtypes of individuals according to their profiles in mindfulness facets and examining the functioning of these profiles in relation to several self-reported indicators of wellbeing and health. The current study extends previous research by exploring mindfulness profiles in adolescents and by providing several sources of indicators (self-reports, parent-reports, and hypothalamic-pituitary-adrenal axis hormones) to examine the adaptive role of these profiles. A sample of 571 adolescents (50.61% girls; 12-17 years old) completed measures of mindfulness, depression, maladaptive schemas, and temperament (neuroticism, extraversion, and effortful control), and provided salivary samples for cortisol and dehydroepiandrosterone sulfate. In addition, 331 adolescents' parents completed measures of their children' temperaments. The results of latent profile analyses supported a three-profile solution: (1) moderate mindfulness (65.5%), (2) judgmental observing (24.2%), and (3) nonjudgmentally aware (10.3%). The judgmental observing profile was associated with a worse adjustment, indicated by higher depressive symptoms, maladaptive schemas, perceived stress, stress-associated hormones, and neuroticism, as well as lower scores on extroversion and effortful control. This profile was more frequent among the oldest adolescents. In contrast, the nonjudgmentally aware group presented a better adjustment and was more frequent among the youngest adolescents. These findings have implications for preventive interventions. Analyzing the specific profile of each adolescent can help improve individual intervention, taking into account the strengths and weaknesses of each adolescent.

Reducing Internalizing Symptoms Among High-Risk, Hispanic Adolescents: Mediators of a Preventive Family Intervention

Familias Unidas is a family-focused preventive intervention that has been found to reduce drug use and sexual risk behaviors among Hispanic adolescents. In some trials, Familias Unidas has also been found to be efficacious in reducing adolescent internalizing symptoms (i.e., depressive and anxiety symptoms), even though the intervention did not specifically target internalizing symptoms. This study examines potential mediators or mechanisms by which Familias Unidas influences internalizing symptoms, specifically the role of intervention-targeted improvements in parent-adolescent communication and reductions in youth externalizing behaviors. A total of 213 Hispanic eighth grade students with a history of externalizing behavior problems and their primary caregivers were recruited from the public school system. Participants, with a mean age of 13.8 years, were randomized into the Familias Unidas intervention or community practice control condition and assessed at baseline, 6, 18, and 30 months post-baseline. A cascading mediation model was tested in which the Familias Unidas intervention was hypothesized to decrease adolescent internalizing symptoms through two mediators: improvements in parent-adolescent communication leading to decreases in externalizing behaviors. Findings show that the intervention had significant direct effects on youth internalizing symptoms at 30 months post-baseline. In addition, the cascading mediation model was supported in which the Familias Unidas intervention predicted significant improvements in parent-adolescent communication at 6 months, subsequently decreasing externalizing behaviors at 18 months, and ultimately reducing youth internalizing symptoms at 30 months post-baseline. Implications for prevention interventions are discussed.

Longitudinal Trajectories of Depression Symptoms in Adolescence: Psychosocial Risk Factors and Outcomes

Variations in symptom trajectories within a population may represent distinct groups with different etiologies and outcomes. This study aimed to identify subgroups of depression symptom trajectories in a sample of adolescents, and to describe psychosocial attributes of the different groups. In a longitudinal study, 243 adolescents (121 males and 122 females), were assessed using a battery of measures of temperament, psychopathology, and psychological and behavioral functioning. Four phases of data collection over 7 years spanned average ages of the participants from 12 to 18 years old. Depressive symptoms from each phase were used to model latent class growth trajectories. A 4-group solution was selected as the best-fitting model: (1) ongoing stable low levels of depression; (2) very high depressive symptoms initially, but a steep decrease in symptoms over time; (3) moderately high depressive symptoms initially, but symptoms decreased over time; and (4) initially low levels of symptoms that increased over time. Trajectory group membership was associated with a range of psychosocial variables including temperament, childhood maltreatment, and young adult quality of life. Characterising these subgroups allows for a better understanding of how the interaction of risk factors increases the likelihood of depression and other poor outcomes, and highlights the importance of early interventions to prevent and treat adolescent depression.

Response to stress in Drosophila is mediated by gender, age and stress paradigm

All living organisms must maintain equilibrium in response to internal and external challenges within their environment. Changes in neural plasticity (alterations in neuronal populations, dendritic remodeling, and synaptic turnover) are critical components of the homeostatic response to stress, which has been strongly implicated in the onset of affective disorders. However, stress is differentially perceived depending on the type of stress and its context, as well as genetic background, age and sex; therefore, an individual's maintenance of neuronal homeostasis must differ depending upon these variables. We established Drosophila as a model to analyze homeostatic responses to stress. Sexually immature and mature females and males from an isogenic wild-type strain raised under controlled environmental conditions were exposed to four reproducible and high-throughput translatable stressors to facilitate the analysis of a large number of animals for direct comparisons. These animals were assessed in an open-field arena, in a light-dark box, and in a forced swim test, as well as for sensitivity to the sedative effects of ethanol. These studies establish that immature and mature females and males represent behaviorally distinct populations under control conditions as well as after exposure to different stressors. Therefore, the neural substrates mediating the stress response must be differentially expressed depending upon the hormonal status of the brain. In addition, an adaptive response to a given stressor in one paradigm was not predictive for outcomes in other paradigms.

Reduced anterior cingulate gray matter volume in treatment-naïve clinically depressed adolescents

Adolescent depression is associated with increased risk for suicidality, social and educational impairment, smoking, substance use, obesity, and depression in adulthood. It is of relevance to further our insight in the neurobiological mechanisms underlying this disorder in the developing brain, as this may be essential to optimize treatment and prevention of adolescent depression and its negative clinical trajectories. The equivocal findings of the limited number of studies on neural abnormalities in depressed youth stress the need for further neurobiological investigation of adolescent depression. We therefore performed a voxel-based morphometry study of the hippocampus, amygdala, superior temporal gyrus, and anterior cingulate cortex (ACC) in 26 treatment-naïve, clinically depressed adolescents and 26 pair-wise matched healthy controls. Additionally, an exploratory whole-brain analysis was performed. Clinically depressed adolescents showed a volume reduction of the bilateral dorsal ACC compared to healthy controls. However, no association was found between gray matter volume of the ACC and clinical severity scores for depression or anxiety. Our finding of a smaller ACC in clinically depressed adolescents is consistent with literature on depressed adults. Future research is needed to investigate if gray matter abnormalities precede or follow clinical depression in adolescents.

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Voxel-based morphometry ROI and exploratory whole-brain analyses were performed

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Depressed adolescents showed a smaller anterior cingulate cortex compared to healthy controls

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No association found between gray matter volume of the effect and clinical scores for depression