Corticotropin-releasing hormone challenge in prepubertal major depression

Biomarkers in Child and Adolescent Depression

Despite the significant prevalence of Major Depressive Disorder in the pediatric population, the pathophysiology of this condition remains unclear, and the treatment outcomes poor. Investigating tools that might aid in diagnosing and treating early-onset depression seems essential in improving the prognosis of the future disease course. Recent studies have focused on searching for biomarkers that constitute biochemical indicators of MDD susceptibility, diagnosis, or treatment outcome. In comparison to increasing evidence of possible biomarkers in adult depression, the studies investigating this subject in the youth population are lacking. This narrative review aims to summarize research on molecular and biochemical biomarkers in child and adolescent depression in order to advocate future directions in the research on this subject. More studies on depression involving the youth population seem vital to comprehend the natural course of the disease and identify features that may underlie commonly observed differences in treatment outcomes between adults and children.

Identification of Key Modules and Genes Associated with Major Depressive Disorder in Adolescents

Major depressive disorder (MDD) is a leading cause of disability worldwide. Adolescence is a crucial period for the occurrence and development of depression. There are essential distinctions between adolescent and adult depression patients, and the etiology of depressive disorder is unclear. The interactions of multiple genes in a co-expression network are likely to be involved in the physiopathology of MDD. In the present study, RNA-Seq data of mRNA were acquired from the peripheral blood of MDD in adolescents and healthy control (HC) subjects. Co-expression modules were constructed via weighted gene co-expression network analysis (WGCNA) to investigate the relationships between the underlying modules and MDD in adolescents. In the combined MDD and HC groups, the dynamic tree cutting method was utilized to assign genes to modules through hierarchical clustering. Moreover, functional enrichment analysis was conducted on those co-expression genes from interested modules. The results showed that eight modules were constructed by WGCNA. The blue module was significantly associated with MDD after multiple comparison adjustment. Several Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with stress and inflammation were identified in this module, including histone methylation, apoptosis, NF-kappa β signaling pathway, and TNF signaling pathway. Five genes related to inflammation, immunity, and the nervous system were identified as hub genes: CNTNAP3, IL1RAP, MEGF9, UBE2W, and UBE2D1. All of these findings supported that MDD was associated with stress, inflammation, and immune responses, helping us to obtain a better understanding of the internal molecular mechanism and to explore biomarkers for the diagnosis or treatment of depression in adolescents.

Maltreatment timing, HPA axis functioning, multigenic risk, and depressive symptoms in African American youth: Differential associations without moderated mediation

Utilizing a large (N = 739), ancestrally homogenous sample, the current study aimed to better understand biological risk processes involved in the development of depressive symptoms in maltreated, African American children age 8-12 years. Maltreatment was independently coded from Child Protective Services records and maternal report. Self-reported depressive symptoms were attained in the context of a week-long, summer research camp. DNA was acquired from buccal cell or saliva samples and genotyped for nine polymorphisms in four hypothalamic-pituitary-adrenal (HPA)-axis-related genes: FKBP5, NR3C1, NR3C2, and CRHR1. Salivary cortisol samples were collected each morning (9 a.m.) and late afternoon (4 p.m.) throughout the week to assess HPA functioning. Results revealed that experiences of maltreatment beginning prior to age 5 were most predictive of depressive symptoms, whereas maltreatment onset after age 5 was most predictive of HPA axis dysregulation (blunted daytime cortisol patterns). Multigenic risk did not relate to HPA functioning, nor did it moderate the relationship between maltreatment and HPA activity. There was no mediation of the relationship between maltreatment and depressive symptoms by HPA dysfunction. Results are interpreted through a developmental psychopathology lens, emphasizing the principle of equifinality while carefully appraising racial differences. Implications for future research, particularly the need for longitudinal studies, and important methodological considerations are discussed.

Strategies for Assessing and Modeling Depressive Symptoms in Longitudinal Studies of Adolescents

Studying age-related change in psychosocial behavior is difficult because manifestation differs with development. While the use of age-appropriate measurement instruments addresses developmental differences, changes in measurement also challenge researchers' ability to study developmental trajectories. Leveraging 8-occasion data from 262 girls (baseline ages 11 and 17 years) participating in a cross-sequential study spanning childhood to adulthood, this paper (1) highlights the needs of developmental researchers seeking to measure change across large swaths of development, (2) forwards an initial formula to convert Beck Depression Inventory-II scores into Children's Depression Inventory scores and facilitate longitudinal analysis and understanding of how depression develops across adolescence, and (3) suggests collection and analysis of new data that would better facilitate researcher's linking of child-, adolescent-, and adult-oriented measurement instruments.

Adolescent Substance Use & Psychopathology: Interactive Effects of Cortisol Reactivity and Emotion Regulation

How are emotional processes associated with the increased rates of substance use and psychological disorders commonly observed during adolescence? An index of emotion-related physiological arousal-cortisol reactivity-and subjective emotion regulation have both been independently linked to substance use and psychological difficulties among youth. The current study (N = 134 adolescents) sought to elucidate the interactive effects of cortisol reactivity following a stressful parent-child interaction task and self-reported emotion regulation ability on adolescents' substance use and externalizing and internalizing behavior problems. Results revealed that adolescents with low levels of cortisol reactivity and high emotion regulation difficulties were more likely to use substances, and also had the highest parent-reported symptoms of oppositional defiant disorder. With respect to internalizing symptoms, high emotion-related physiological reactivity coupled with high emotion regulation difficulties were associated with higher self-reported major depression symptoms among youth. Findings reveal that different profiles of HPA axis arousal and emotion regulation are associated with substance use and symptoms of psychopathology among adolescents.

HPA-axis stress reactivity in youth depression: evidence of impaired regulatory processes in depressed boys

Given the link between youth depression and stress exposure, efforts to identify related biomarkers have involved examinations of stress regulation systems, including the hypothalamic-pituitary-adrenal (HPA) axis. Despite these vast efforts, the underlying mechanisms at play, as well as factors that may explain heterogeneity of past findings, are not well understood. In this study, we simultaneously examined separate components of the HPA-axis response (e.g. activation intensity, peak levels, recovery) to the Socially Evaluated Cold-Pressor Test in a targeted sample of 115 youth (age 9-16), recruited to overrepresent youth with elevated symptoms of depression. Among youth who displayed a cortisol response to the task, depression symptoms were associated with higher peak responses but not greater rate of activation or recovery in boys only. Among those who did not respond to the task, depression symptoms were associated with greater cortisol levels throughout the visit in boys and girls. Results suggest that depression symptoms are associated with a more prolonged activation of the axis and impaired recovery to psychosocial stressors primarily in boys. We discussed two potential mechanistic explanations of the link between depression symptoms and the duration of activation: (1) inhibitory shift (i.e. point at which the ratio of inhibitory and excitatory input into the axis shifts from greater excitatory to greater inhibitory input) or (2) inhibitory threshold (i.e. level of cortisol exposure required to activate the axis' feedback inhibition system).

Cortisol response to psychosocial stress during a depressive episode and remission

This study compared cortisol responses to a standardized psychosocial stressor during a major depressive episode (MDE) and again during remission in adolescents and young adults. Twenty-six individuals with no personal or family history of a major psychiatric disorder (NC) and 24 individuals with a diagnosis of major depressive disorder (MDD) at Time 1 participated in the study. The MDD group showed robust cortisol responses during their index episode and after recovery. In contrast, the NC group showed habituation to the repeated psychosocial stressor, as evident in a flatter cortisol response profile at Time 2. Within the MDD group, net peak cortisol during the first stress test was positively associated with the duration of the index MDE and negatively associated with the total duration of all MDEs. Whereas summary indices of cortisol responses were relatively stable across repeated stress tasks within the MDD group, this was not the case for NC. Results demonstrate that cortisol responses fail to habituate to repeated psychosocial stress during recovery from an MDE and could reflect a trait-like marker of risk for recurrence.

Examining the developmental interface of cortisol and depression symptoms in young adolescent girls

Despite the substantial amount of data supporting a link between HPA-axis functioning and depression, the ontogeny of this association is not known. The aim of the present study was to contribute data on the developmental interface of HPA-axis functioning and depression in girls by testing associations between repeated measures of depression symptoms and cortisol levels in childhood and early adolescence. Girls (N=232) and their mothers, who were participating in a longitudinal study, were interviewed about depression symptoms annually from ages 9 to 12 years. Cortisol was assayed from saliva at ages 10 and 12 years upon arrival to the lab and following administration of the cold pressor task (CPT). Time of day of collection of saliva and level of pubertal development were included as covariates in model testing. Although most girls did not show an increase in cortisol in response to the CPT, lower levels of output during the CPT were associated with higher levels of depression symptoms. These findings were observed only for cortisol levels assessed at age 12 years. Girls with low levels of cortisol output at age 12, and decreases in output from ages 10 to 12, had stable or slightly increasing depression symptoms from ages 9 to 12 years. We conclude that associations between HPA-axis functioning and depression emerge as early as age 12. However, individual differences in cortisol levels at age 12 also were associated with depression symptoms at earlier ages. The data suggest two possibilities: (1) that childhood depression is associated with HPA-axis dysregulation, but that age related changes in the sensitivity or plasticity of the HPA-axis may result in a delay in the emergence of such an association, or (2) that dysregulation of the functioning of the HPA-axis develops following repeated experience of depression symptoms.

In search of HPA axis dysregulation in child and adolescent depression

Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis in adults with major depressive disorder is among the most consistent and robust biological findings in psychiatry. Given the importance of the adolescent transition to the development and recurrence of depressive phenomena over the lifespan, it is important to have an integrative perspective on research investigating the various components of HPA axis functioning among depressed young people. The present narrative review synthesizes evidence from the following five categories of studies conducted with children and adolescents: (1) those examining the HPA system’s response to the dexamethasone suppression test (DST); (2) those assessing basal HPA axis functioning; (3) those administering corticotropin-releasing hormone (CRH) challenge; (4) those incorporating psychological probes of the HPA axis; and (5) those examining HPA axis functioning in children of depressed mothers. Evidence is generally consistent with models of developmental psychopathology that hypothesize that atypical HPA axis functioning precedes the emergence of clinical levels of depression and that the HPA axis becomes increasingly dysregulated from child to adult manifestations of depression. Multidisciplinary approaches and longitudinal research designs that extend across development are needed to more clearly and usefully elucidate the role of the HPA axis in depression.

Clinical characteristics of depression among adolescent females: a cross-sectional study

BACKGROUND

Adolescents rarely seek psychiatric help; they even hesitate to disclose their feelings to their parents. However; the adolescents especially the females experience depressive symptoms more frequently than general population. Do they experience classic depressive symptoms? Are there symptoms specific to this subpopulation?

AIM OF THE STUDY

Through this study, the authors aimed to estimate the prevalence of depressive disorders in Egyptian adolescent female students. They also expected a characteristic profile of symptoms for the adolescent females. However available literature provides no guidance in the description of this profile of symptoms.

METHODS

A number of 602 adolescent females were interviewed, and subjected to General Health Questionnaire (GHQ); Children Depression Inventory (CDI), Structured Clinical Interview for DSM-IV Axis-I Disorders (SCID-I), then Hamilton Rating Scale for Depression (Ham-D). Results were analyzed by the use of SPSS-15.

RESULTS

The study revealed the prevalence of depression in the sample of the study to be 15.3% (measured by CDI), and 13.3% (measured by SCID-I). Fatigue was the most common presenting depressive symptom (81.3%), in addition to other emotional, cognitive and physiological symptoms. Suicidal ideations were the most common suicidal symptoms in depressed adolescent females (20%), with 2.5% serious suicidal attempts.

CONCLUSIONS

The somatic symptoms were by far the most common presenting symptom for female adolescents suffering from depressive disorders. Depressive phenomena including unexplained fatigue, decreased energy, psychomotor changes, lack of concentration, weight changes and suicidal ideations may be the presenting complaints instead of the classic sad mood.

Behavioral adjustment in a community sample of boys: links with basal and stress-induced salivary cortisol concentrations

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been observed in association with internalizing symptoms and is thought to be involved in the pathogenesis of depression and some anxiety disorders. This study examined basal and stress-induced cortisol concentrations in relation to internalizing and externalizing symptoms in a racially mixed community sample of 102 8-11-year-old boys. Afternoon basal cortisol concentrations were positively correlated with measures of internalizing behavior problems, social problems, and emotionality. Greater change in cortisol across a home-visit challenge task was also significantly associated with internalizing behaviors and social problems, as well as attention and thought problems. The implications of these findings and how they may relate to the pathogenesis of emotional and behavioral problems are discussed.

Brain-derived neurotrophic factor gene and protein expression in pediatric and adult depressed subjects

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a member of a neurotrophin family and is involved in many physiological functions, including cell proliferation, migration, and differentiation, and neuron survival in the human nervous system. Abnormalities of BDNF have been implicated in the pathophysiology of depression based on observations that antidepressant drugs cause increases in the levels of BDNF in rat brains and its abnormalities have appeared in the serum of depressed patients and in postmortem brains of suicide victims.

METHODS

We examined the gene expression of BDNF in the lymphocytes and protein expression in the platelets of adult and pediatric depressed patients during a drug-free period. We determined BDNF gene expression using a quantitative RT-PCR method and protein expression using the ELISA method.

RESULTS

We observed that the gene expression of BDNF was significantly decreased in the lymphocytes of adult and pediatric depressed patients compared with normal control subjects. Similarly, the protein expression of BDNF was significantly decreased in the platelets of adult and pediatric depressed patients compared with normal control subjects.

CONCLUSIONS

To our knowledge, this is the first study that reports a decrease in BDNF gene expression in the peripheral cells of depressed patients. Because of the bidirectional movement of BDNF between the periphery and the CNS, the reduced gene expression in the lymphocytes and the protein expression in the platelets may be an index of similar abnormalities in the brain and could be a target for antidepressant drugs.

Neurobiological adaptations to violence across development

Developmental adaptations to violent environments involve a multitude of cascading effects spanning many levels of analysis from genes to behavior. In this review, we (a) examine the potentiating effects of violence on genetic vulnerabilities and the functioning of neurotransmitter systems in producing both internalizing and externalizing psychopathology; (b) describe implications of violence exposure for brain development, particularly within the hippocampus and prefrontal cortex; and (c) consider the effects of violence on developing human stress and startle responses. This review integrates literatures on the developmental effects of violence among rodents, nonhuman primates, and humans. Many neurobiological changes that are adaptive for survival in violent contexts become maladaptive in other environments, conferring life-long risk for psychopathology.

Hypothalamic-pituitary-adrenal axis dysregulation in depressed children and adolescents: a meta-analysis

Research findings on the hypothalamic-pituitary-adrenal (HPA) axis and pediatric depression reflect a variety of methodological approaches that tap different facets of HPA-axis functions. Partly owing to the methodological heterogeneity of studies, descriptive reviews of this area have produced inconsistent conclusions. Therefore, we conducted formal meta-analyses of pertinent studies in order to advance our understanding of HPA-axis dysregulation in pediatric depression. We examined: (a) 17 published studies of HPA-axis response to the dexamethasone suppression test (DST) in depressed youth (DST; N=926) and (b) 17 studies of basal HPA-axis functioning (N=1332). We also examined descriptively studies that used corticotropin-releasing hormone (CRH) infusion, and those that used psychological probes of the HPA-axis. The global standardized mean effect size difference in HPA-axis response to the DST between depressed and non-depressed youth was 0.57, z=4.18, p<0.01. The global standardized mean difference effect size in basal HPA-axis functioning was 0.20, z=4.53, p<0.01. Age, sex, timing of sampling, dexamethasone dosage, or type of control group was not a significant source of variability for the DST or basal studies. In addition, when compared to non-depressed peers, depressed youth have a normative response to CRH infusion but an overactive response to psychological stressors. In conclusion, the HPA-axis system tends to be dysregulated in depressed youth, as evidenced by atypical responses to the DST, higher baseline cortisol values, and an overactive response to psychological stressors. This pattern of dysregulation suggests anomalies within the axis's negative feedback system and CRH production, but intact pituitary and adrenal sensitivity.

Altered amygdala and hippocampus function in adolescents with hypercortisolemia: a functional magnetic resonance imaging study of Cushing syndrome

Chronic elevations of endogenous cortisol levels have been shown to alter medial temporal cortical structures and to be accompanied by declarative memory impairments and depressive symptoms in human adults. These effects of elevated endogenous levels of cortisol have not been directly studied in adolescents. Because adolescents with Cushing syndrome show endogenous elevations in cortisol, they represent a unique natural model to study the effects of prolonged hypercortisolemia on brain function, and memory and affective processes during this developmental stage. Using functional magnetic resonance imaging (fMRI), we compared 12 adolescents with Cushing syndrome with 22 healthy control adolescents on amygdala and anterior hippocampus activation during an emotional faces encoding task. None of these adolescents manifested depressive symptoms. Encoding success was assessed using a memory recognition test performed after the scan. The fMRI analyses followed an event-related design and were conducted using the SPM99 platform. Compared to healthy adolescents, patients with Cushing syndrome showed greater left amygdala and right anterior hippocampus activation during successful face encoding. Memory performance for faces recognition did not differ between groups. This first study of cerebral function in adolescents with chronic endogenous hypercortisolemia due to Cushing syndrome demonstrates the presence of functional alterations in amygdala and hippocampus, which are not associated with affective or memory impairments. Such findings need to be followed by work examining the role of age and related brain maturational stage on these effects, as well as the identification of possible protective factors conferring resilience to affective and cognitive consequences in this disease and/or during this stage of cerebral development.

Salivary cortisol and psychopathology in children bereaved by the september 11, 2001 terror attacks

BACKGROUND

Studies suggest that stressful events increase risk for childhood anxiety and depression and hypothalamic-pituitary-adrenal (HPA) axis dysregulation. This prospective longitudinal study evaluated relationships among severe psychosocial stress, psychiatric morbidity, and HPA axis function in children.

METHODS

Forty-five children (mean age: 8.9 +/- 2.9 years) suffering parent death from September 11, 2001 terror attacks and 34 nonbereaved children (mean age: 9.3 +/- 2.5 years) were evaluated prospectively at 6-month intervals in this 2-year study. Assessments involved diagnostic interviews (Child Schedule for Affective Disorders and Schizophrenia [K-SADS]) for psychopathology and 3 days of baseline salivary cortisol and a salivary dexamethasone suppression test for HPA axis function.

RESULTS

Bereaved children, but not nonbereaved children, had significantly increased rates of psychiatric disorders involving anxiety disorders, especially posttraumatic stress disorder (PTSD), after September 11, 2001 compared with retrospective assessments before September 11, 2001. Morning (AM) and 4:00 pm baseline cortisol were significantly and persistently higher for bereaved than nonbereaved children. Compared with bereaved children without psychopathology, bereaved children with PTSD had significantly lower 4:00 pm baseline cortisol and significantly greater 4:00 pm cortisol suppression. Children with generalized anxiety disorder had significantly less AM cortisol suppression than children without psychopathology.

CONCLUSIONS

Children bereaved by sudden, unexpected parent death had persistent psychological dysfunction and HPA axis dysregulation in this study.

Neurobiology of depression in children and adolescents

This article reviews classical and updated studies of the neurobiology of depressive disorders in children and adolescents. Most studies of childhood and adolescent depression and suicide have followed up the observations and methods used in studies in adults. These studies include neuroendocrine studies, which particularly look at the hypothalamic-pituitary-adrenal axis, the serotonergic system, peripheral blood and cerebrospinal fluid biologic markers, genetics, gene-environment interactions and sleep studies, and neuroimaging and postmortem studies, although in these areas the number of studies is limited.

Pharmacotherapy of depressed children and adolescents: current issues and potential directions

The recent deliberations by the U.S. Food and Drug Administration (FDA) regarding the relationship between antidepressants and suicidality in children have incited debates about the safety of these medications for the treatment of pediatric depression. In light of these events, this review discusses four issues pertaining to pharmacotherapy for pediatric depression. First, we summarize pertinent data from randomized controlled trials of antidepressants for pediatric depression. These data provide strong support for fluoxetine and modest support for the other antidepressants. Second, we examine the outcome of the FDA meta-analysis of the data on antidepressant-induced suicidality, with specific emphasis on the methodological limitations of this analysis. Third, we consider the collective implications of the antidepressant efficacy and suicidality data on clinical practice. Specifically, we present several compelling arguments that justify the continued use of antidepressants for pediatric depression, despite the inherent limitations of these medications. Finally, we review several pathophysiological factors that might provide insights into treatment response and impact the design of future pharmacotherapy studies of depression. These factors relate to diagnostic heterogeneity, developmental consistency, and psychobiology. Potentially novel pharmacotherapies are also discussed.

Maternal and environmental factors influence the hypothalamic–pituitary–adrenal axis response to corticotropin-releasing hormone infusion in offspring of mothers with or without mood disorders

Individuals with melancholic major depression exhibit basal hypercortisolism and an attenuated ACTH response to exogenous corticotropin-releasing hormone (CRH) infusion. Given the greater incidence of depression in children of depressed parents, we examined the ACTH and cortisol responses to ovine CRH (oCRH) infusion in 63 adolescent offspring of mothers with major depression, bipolar illness, or no psychiatric illness. Psychiatric and observational assessments of these families had been conducted over the course of 10 years preceding this study. We examined the children's responses to CRH in relation to maternal characteristics and family environment and found the following: (a) cortisol responses were negatively related to chronic family stress and (b) offspring of depressed mothers with an avoidant personality disorder showed an exaggerated ACTH response. In addition, adolescents in late puberty (Tanner 4 and 5) had lower ACTH and cortisol responses to oCRH infusion than those in early puberty. Further, offspring with early histories of mood problems, and those who developed major depressive disorder as young adults, did not exhibit basal hypercortisolism but did show an attenuated ACTH response to CRH. Our results add to the growing body of literature showing the influence of maternal characteristics and environmental factors on hypothalamic-pituitary-adrenal axis patterns in children.

Peri-sleep-onset cortisol levels in children and adolescents with affective disorders

BACKGROUND

Changes in the hypothalamic-pituitary-adrenal (HPA) axis, as evidenced by patterns of cortisol secretion, have been of interest in understanding depression and anxiety disorders across the life span. Previous studies of pediatric depression have pointed to the period around sleep onset as a key time point for observing alterations in cortisol secretion associated with affective disorders. Evidence also indicates that pubertal development may influence the expression of HPA dysregulation. We hypothesized that adolescents with depression and youth with anxiety disorders exhibit elevated peri-sleep-onset cortisol.

METHODS

Plasma cortisol was sampled every 20 min around sleep onset from children and adolescents with major depressive disorder (n = 116), anxiety disorders (n = 32), or no history of psychiatric disorder (control; n = 76). Sleep onset was determined by polysomnography. Classification of participants as children or adolescents was based on Tanner staging of pubertal maturation.

RESULTS

Children with anxiety disorders had higher peri-sleep-onset cortisol than children with depression or control children. Adolescents with depression had marginally higher peri-sleep-onset cortisol than control adolescents and significantly higher peri-sleep-onset cortisol than children with depression.

CONCLUSIONS

Depression and anxiety are associated with altered cortisol secretion around sleep onset, and these changes appear to be influenced by pubertal maturation.

Two different putative genetic animal models of childhood depression

BACKGROUND

In an attempt to model childhood depression, we examined whether existing genetic animal models of depression in adult rats are also valid in prepubertal rats.

METHODS

Two different "depressed" rat lines were studied: the Flinders Sensitive Line (FSL) and their controls, Sprague-Dawley (SD); and the Wistar Kyoto (WKY) line and their controls, Wistar. We hypothesized that male prepubertal FSL and WKY rats would show increased swim test immobility and different patterns of social play and of basal plasma levels of corticosterone and adrenocorticotropic hormone (ACTH) compared with control rats.

RESULTS

Prepubertal FSL and WKY rats exhibited significantly longer duration of immobility than control rats in the swim test. The FSL rats demonstrated significantly higher levels of social play behaviors and lower levels of corticosterone and ACTH compared with SD control rats, whereas WKY rats demonstrated significantly lower levels of social play behaviors and higher plasma levels of corticosterone and ACTH compared with Wistar control rats.

CONCLUSIONS

The results might suggest that prepubertal FSL and WKY rats are both putative genetic animal models of childhood depression, exhibiting separate patterns and symptoms of childhood depression.

Child maltreatment and HPA axis dysregulation: relationship to major depressive disorder and post traumatic stress disorder in females

A history of child maltreatment increases the vulnerability to the development of Major Depressive Disorder (MDD) and/or Posttraumatic Stress Disorder (PTSD), especially in females. Both MDD and PTSD are associated with a dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. Dysregulation of the HPA axis may be an important etiological link between child maltreatment and subsequent psychiatric disorder, yet little is known about the relationship between exposure and outcome. The aim of this review is to explore the role of HPA axis dysregulation in the link between child maltreatment and MDD/PTSD among women. Studies of females with MDD frequently indicate a hyperactivity of the HPA axis, and contribute to our understanding of the underlying mechanisms involved in mood dysregulation. Evidence for HPA axis dysregulation in PTSD is less convincing and suggests that timing of the stressful experience as well as the type of the trauma may influence the outcome. The strongest evidence to date suggesting that the development of the HPA axis may be affected by early life stressful experiences comes from pre-clinical animal studies. Together these studies add to our understanding of the role of the HPA axis in psychiatric disorders in relation to stress. The literature on HPA axis function in both children and adults following child maltreatment further highlights the potential relevance of early stress to later onset of major psychiatric disorders. Such knowledge may also contribute to the development of early interventions targeted at primary prevention.

Altering the course of neurodevelopment: a framework for understanding the enduring effects of psychotropic drugs

Childhood is a time filled with wondrous changes, as brain plasticity permits experiences to shape the immature brain to meet the demands of the environment. Change occurs at various levels--from neuroanatomy, including within a given region and its connectivity to other regions, to the function of neurotransmitter systems and their reactivity to pharmacological agents in the short- and long-term. The nature and degree to which drug exposure influences the final adult topography is influenced greatly by the maturational phase of these critical factors. Moreover, evidence is slowly emerging that suggests that the long-term effects of drug exposure are delayed and expressed once the vulnerable system reaches maturation (i.e., typically during adulthood). This phenomenon is known as neuronal imprinting and occurs when the effects of drug exposure outlast the drug itself. Thus, understanding the persistent effects critically depends on the window of observation. Embracing this concept should influence how we conduct preclinical assessments of developmental drug exposure, and ultimately how we conduct clinical assessments of drug efficacy, effectiveness, and safety for the treatment of childhood psychiatric disorders. In this article, we present a model to provide a heuristic framework for making predictions about imprinted effects of childhood drug exposure. We then review epidemiological data on attention deficit hyperactivity disorder (ADHD) and childhood depression, prescription practices, and what is known regarding the long-term consequences of drug exposure in these populations. We conclude with a discussion of the current status of preclinical studies on juvenile stimulant exposure.

Gastrointestinal distress to serotonergic challenge: a risk marker for emotional disorder?

OBJECTIVE

Serotonin is an important mediator of gut sensation and motility. The authors' aim was to determine whether inadvertent gastrointestinal (GI) distress to serotonergic challenge predicted future major depressive and/or anxiety disorders in exposed children.

METHOD

l-5-hydroxytryptophan was administered to 119 prepubertal children free of psychiatric disorder as part of a psychobiological cohort study initially designed to examine familial loading for mood disorder as the exposure of interest. Subjects were followed longitudinally with standardized psychiatric interviews to identify new-onset mood and anxiety disorders over 90.3 +/- 29.2 months, with the average assessment interval being 16.6 +/- 6.2 months. Reports of GI distress in a subgroup during serotonergic challenge led the authors to examine GI distress to infusion as an exposure post hoc and to perform survival analysis using major depressive and/or anxiety disorders as the outcomes of interest.

RESULTS

GI distress to serotonergic challenge was experienced by 23 subjects, with 7 (30.4%) developing an emotional disorder during follow-up in comparison to 12 (10.4%) of 96 nondistressed subjects. The distressed group was at significantly greater risk of subsequent major depression and/or anxiety (p =.026), even after controlling for family history of psychiatric disorder.

CONCLUSIONS

GI distress to serotonergic challenge in childhood is associated with heightened risk for subsequent major depressive and/or anxiety disorders. Studies of serotonergic neurotransmission may aid our understanding of nonrandom associations between functional GI symptoms and emotional symptoms and disorders.

Persistent central nervous system effects of an adverse early environment: clinical and preclinical studies

In the search for the underlying biological causes of psychiatric disorders, primary roles for both genetics and environment have been clearly established. A family history of mood or anxiety disorders, representing the genetic component, clearly increases the risk for developing these illnesses in adulthood. The pivotal role of early environmental influences in the pathogenesis of these disorders is also supported by an abundance of both clinical and preclinical data. This review will highlight some of the preclinical and clinical literature that suggests early adverse experience may sensitize corticotropin-releasing factor (CRF) circuitry. The neurobiology of depression highlighting the pathophysiological role of CRF is reviewed. Next, some of the preclinical models of early life stress are discussed; along with a review of the relevant clinical literature that suggests that the functional dysregulation of CRF circuitry in response to early life trauma may contribute to adulthood depression. The discussion will be framed in regards to a stress-diathesis model in which early adverse events result in a sensitized stress axis that predisposes individuals to develop mood disorders.

Possible role of cortisol and dehydroepiandrosterone in human development and psychopathology

BACKGROUND

The characteristics of adrenal hormone secretion change markedly during infancy. Disturbances in basal levels may precipitate psychological dysfunction and are associated with psychopathology in young people.

AIMS

To relate three aspects of behavioural endocrinology: developmental changes in cortisol and dehydroepiandrosterone (DHEA), the role of these hormones in the psychopathology of young people, and the action of these steroids in the brain.

METHOD

A selective review from the human developmental, psychiatric and neurosciences literature.

RESULTS

There are developmentally mediated changes in brain sensitivity following excess exposure to cortisol. This may result in impairments of mental and behavioural function. DHEA and gonadal steroids may modulate the actions of cortisol.

CONCLUSIONS

Steroid hormones contribute to shaping behavioural function during early development and act as risk factors for psychopathology.

The role of childhood trauma in the neurobiology of mood and anxiety disorders: preclinical and clinical studies

Epidemiologic studies indicate that children exposed to early adverse experiences are at increased risk for the development of depression, anxiety disorders, or both. Persistent sensitization of central nervous system (CNS) circuits as a consequence of early life stress, which are integrally involved in the regulation of stress and emotion, may represent the underlying biological substrate of an increased vulnerability to subsequent stress as well as to the development of depression and anxiety. A number of preclinical studies suggest that early life stress induces long-lived hyper(re)activity of corticotropin-releasing factor (CRF) systems as well as alterations in other neurotransmitter systems, resulting in increased stress responsiveness. Many of the findings from these preclinical studies are comparable to findings in adult patients with mood and anxiety disorders. Emerging evidence from clinical studies suggests that exposure to early life stress is associated with neurobiological changes in children and adults, which may underlie the increased risk of psychopathology. Current research is focused on strategies to prevent or reverse the detrimental effects of early life stress on the CNS. The identification of the neurobiological substrates of early adverse experience is of paramount importance for the development of novel treatments for children, adolescents, and adults.

Are child-, adolescent-, and adult-onset depression one and the same disorder?

This paper reviews prior research studies examining neurobiological correlates and treatment response of depression in children, adolescents, and adults. Although there are some similarities in research findings observed across the life cycle, both children and adolescents have been found to differ from depressed adults on measures of basal cortisol secretion, corticotropin stimulation post-corticotropin releasing hormone (CRH) infusion, response to several serotonergic probes, immunity indices, and efficacy of tricyclic medications. These differences are proposed to be due to 1) developmental factors, 2) stage of illness factors (e.g., number of episodes, total duration of illness), or 3) heterogeneity in clinical outcome (e.g., recurrent unipolar course vs. new-onset bipolar disorder). Relevant clinical and preclinical studies that provide support for these alternate explanations of the discrepant findings are reviewed, and directions for future research are discussed. To determine whether child-, adolescent-, and adult-onset depression represent the same condition, it is recommended that researchers 1) use the same neuroimaging paradigms in child, adolescent, and adult depressed cohorts; 2) carefully characterize subjects' stage of illness; and 3) conduct longitudinal clinical and repeat neurobiological assessments of patients of different ages at various stages of illness. In addition, careful attention to familial subtypes (e.g., depressive spectrum disorders vs. familial pure depressive disorders) and environmental factors (e.g., trauma history) are suggested for future investigations.

The neuroscience of depression in adolescence

The neuroscience of depression in children and adolescents has only recently become a focus of research. Initially, techniques previously used for adult investigations were employed, such as endocrine studies and sleep studies. Endocrine studies have indicated that, as in adult depression, a dysregulation of the serotonin (5-HT) axis is involved in childhood depression. However, both of these techniques are difficult to perform in children and have yielded some inconsistent results. The more recently developed neuroimaging techniques should enable the greatest advances in our understanding of the pathophysiology of depression. These techniques have already implicated the frontal lobes in the pathogenesis of depression in children and adolescents, and further research is ongoing.

A.E. Bennett Research Award. Developmental traumatology. Part I: Biological stress systems

BACKGROUND

This investigation examined the relationship between trauma, psychiatric symptoms and urinary free cortisol (UFC) and catecholamine (epinephrine [EPI], norepinephrine [NE], dopamine [DA]) excretion in prepubertal children with posttraumatic stress disorder (PTSD) secondary to past child maltreatment experiences (n = 18), compared to non-traumatized children with overanxious disorder (OAD) (n = 10) and healthy controls (n = 24).

METHODS

Subjects underwent comprehensive psychiatric and clinical assessments and 24 hour urine collection for measurements of UFC and urinary catecholamine excretion. Biological and clinical measures were compared using analyses of variance.

RESULTS

Maltreated subjects with PTSD excreted significantly greater concentrations of urinary DA and NE over 24 hours than OAD and control subjects and greater concentrations of 24 hour UFC than control subjects. Post hoc analysis revealed that maltreated subjects with PTSD excreted significantly greater concentrations of urinary EPI than OAD subjects. Childhood PTSD was associated with greater co-morbid psychopathology including depressive and dissociative symptoms, lower global assessment of functioning, and increased incidents of lifetime suicidal ideation and attempts. Urinary catecholamine and UFC concentrations showed positive correlations with duration of the PTSD trauma and severity of PTSD symptoms.

CONCLUSIONS

These data suggest that maltreatment experiences are associated with alterations of biological stress systems in maltreated children with PTSD. An improved psychobiological understanding of trauma in childhood may eventually lead to better treatments of childhood PTSD.

Psychoneuroendocrinology of children and adolescents

This article reviews psychoneuroendocrinologic approaches to the understanding of internalizing disorders (depression and anxiety disorders) and externalizing disorders. This article discusses three specific psychoneuroendocrine systems: measures of the hypothalamic-pituitary-adrenal (HPA) axis, measure of the serotonergic function, and measures of the growth-hormone (GH) response to pharmacologic challenge. The hypothalamic-pituitary-adrenal (HPA) axis is the main system; understanding this system may reveal information on the permissive and etiologic relationship of stress to psychiatric disorder.

Depressive disorder in children and adolescents

Depression is a relatively common health issue in children and adolescents. Different pathogenetic factors are implied: genetic, biological, psychological and environmental. The core symptoms of depression are the same for children, adolescents and adults but the prominence of characteristic symptoms changes with age. The clinical picture of depression according to age level is described in different types of mood disorders (major depressive disorder, dysthymia, bipolar disorder) and in mental retardation. Over half of the youths with depression have comorbid conditions: anxiety disorders, other mood disorders, attention deficit/hyperactivity disorder, and conduct disorders. Different factors affect the natural course and risk of suicide. Assessment procedures of depression and comorbid conditions include a psychiatric evaluation of the depressed subject and his family, structured interviews and specific rating scales. A comprehensive treatment strategy, psychoeducational, psychotherapeutic and psychopharmacological, is proposed.

The corticotropin-releasing hormone challenge in depressed abused, depressed nonabused, and normal control children

Hypothalamic-pituitary-adrenal (HPA) axis disturbances in depressed children with a history of abuse were examined. Thirteen depressed abused, 13 depressed nonabused, and 13 normal control children were given 1.0 microgram/kg of human corticotropin-releasing hormone (CRH) intravenously. Blood samples for corticotropin (ACTH) and cortisol were obtained at nine intervals. When compared to depressed nonabused and normal control children, depressed abused children had significantly greater peak, total, and net ACTH secretion post-CRH. Increased ACTH secretion was only observed in depressed abused children experiencing ongoing chronic adversity (marital violence, emotional abuse, poverty, lack of supports). The pattern of findings of the depressed abused children experiencing ongoing adversity parallels the pattern of HPA axis dysregulation reported in animal studies of chronic stress. They add to a growing body of literature suggesting measures of past trauma and current adversity are important sources of variability in psychobiological correlates of major depression.

Childhood and adolescent depression: a review of the past 10 years. Part I

OBJECTIVE

To qualitatively review the literature of the past decade covering the epidemiology, clinical characteristics, natural course, biology, and other correlates of early-onset major depressive disorder (MDD) and dysthymic disorder (DD).

METHOD

A computerized search for articles published during the past 10 years was made and selected studies are presented.

RESULTS

Early-onset MDD and DD are frequent, recurrent, and familial disorders that tend to continue into adulthood, and they are frequently accompanied by other psychiatric disorders. These disorders are usually associated with poor psychosocial and academic outcome and increased risk for substance abuse, bipolar disorder, and suicide. In addition, DD increases the risk for MDD. There is a secular increase in the prevalence of MDD, and it appears that MDD is occurring at an earlier age in successive cohorts. Several genetic, familial, demographic, psychosocial, cognitive, and biological correlates of onset and course of early-onset depression have been identified. Few studies, however, have examined the combined effects of these correlates.

CONCLUSIONS

Considerable advances have been made in our knowledge of early-onset depression. Nevertheless, further research is needed in understanding the pathogenesis of childhood mood disorders. Toward this end, studies aimed at elucidating mechanisms and interrelationships among the different domains of risk factors are needed.

Nocturnal ACTH, cortisol, growth hormone, and prolactin secretion in prepubertal depression

OBJECTIVE

To examine nocturnal secretion of adrenocorticotropin, cortisol, growth hormone, and prolactin in 38 medically healthy children with prepubertal major depression compared with 28 medically and psychiatrically healthy control children.

METHOD

Prior to sampling, subjects underwent an "adaptation night" with the intravenous catheter in place and electroencephalographic (EEG) electrodes for standard all-night polysomnogram. On the following night, plasma samples were obtained every 20 minutes through an indwelling catheter. Hormonal concentrations were measured by specific radioimmunoassay and aligned by EEG-confirmed sleep onset. Areas under the curve were calculated for total secretion and compared using analysis of variance.

RESULTS

Prepubertal depressed children had lower cortisol secretion during the first 4 hours after sleep onset compared with controls. Adrenocorticotropin, prolactin, and growth hormone secretion did not differ between groups. Examination of clinical characteristics in depressed children revealed lower nocturnal adrenocorticotropin concentrations in depressed inpatients versus depressed outpatients and in depressed sexually abused versus depressed nonabused children. A significant sex by diagnosis effect revealed lower growth hormone secretion in depressed females compared with depressed males.

CONCLUSIONS

In contrast to neuroendocrine challenge studies in these same subjects, nocturnal neuroendocrine measures did not reveal any of the expected group differences. These results emphasize the contrasts between unstimulated and challenge studies of neuroendocrine secretion and of the importance of considering clinical characteristics and maturation influences in biological studies of prepubertal depression.