Mechanisms underlying the comorbidity between depressive and addictive disorders in adolescents: interactions between stress and HPA activity

Neuroendocrine mechanisms in the links between early life stress, affect, and youth substance use: A conceptual model for the study of sex and gender differences

Early life stress (ELS) is defined as an acute or chronic stressor that negatively impacts a child's development. ELS is associated with substance use and mental health problems. This narrative literature review focuses on sex and gender differences in the effects of ELS on 1) adolescent neuroendocrine development; 2) pubertal brain maturation; and 3) development of internalizing symptoms and subsequent substance use. We posit that ELS may generate larger hormonal dysregulation in females than males during puberty, increasing internalizing symptoms and substance use. Future research should consider sex and gender differences in neuroendocrine developmental processes when studying the link between ELS and negative health outcomes.

Sex Differences in the Relationship Between Nucleus Accumbens Volume and Youth Tobacco or Marijuana Use Following Stressful Life Events

Background

Exposure to stressful life events (SLEs) can upset balance and affect the healthy brain development of children and youths. These events may influence substance use by altering brain reward systems, especially the nucleus accumbens (NAc), which plays a key role in motivated behaviors and reward processing. The interaction between sensitization to SLEs, depression, and substance use might vary between male and female youths, potentially due to differences in how each sex responds to SLEs.

Aims

This study aims to examine the effect of sex on the relationship between SLEs, Nucleus Accumbens activity, and substance use in a nationwide sample of young individuals.

Methods

We utilized data from the Adolescent Brain Cognitive Development study (ABCD), a longitudinal study of pre-adolescents aged 9-10 years, comprising 11,795 participants tracked over 36 months. Structured interviews measuring SLEs were conducted using the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS). Initial linear regression analyses explored if SLEs could predict volumes of the right and left NAc. Subsequently, Cox regression models were used to investigate how SLEs and NAc volume might predict the initiation of tobacco and marijuana use, with the analysis stratified by sex to address potential sex differences.

Results

Our findings reveal that SLEs significantly predicted marijuana use in males but not in females, and tobacco use was influenced by SLEs in both sexes. A higher number of SLEs was linked with decreased left NAc volume in males, a trend not seen in females. The right NAc volume did not predict substance use in either sex. However, volumes of both the right and left NAc were significant predictors of future tobacco use, with varying relationships across sexes. In females, an inverse relationship was observed between both NAc volumes and the risk of tobacco use. In contrast, a positive correlation existed between the left NAc volume and tobacco and marijuana use in males, with no such relationship for females.

Conclusion

This study underscores that the associations between SLEs, NAc volume, and subsequent substance use are influenced by a nuanced interplay of sex, brain hemisphere, and substance type.

Dampened psychobiological responses to stress and substance use in adolescence

Substance use increases throughout adolescence, and earlier substance use may increase risk for poorer health. However, limited research has examined whether stress responses relate to adolescent substance use, especially among adolescents from ethnic minority and high-adversity backgrounds. The present study assessed whether blunted emotional and cortisol responses to stress at age 14 related to substance use by ages 14 and 16, and whether associations varied by poverty status and sex. A sample of 277 Mexican-origin youth (53.19% female; 68.35% below the poverty line) completed a social-evaluative stress task, which was culturally adapted for this population, and provided saliva samples and rated their anger, sadness, and happiness throughout the task. They also reported whether they had ever used alcohol, marijuana, cigarettes, and vaping of nicotine at age 14 and again at age 16. Multilevel models suggested that blunted cortisol reactivity to stress was associated with alcohol use by age 14 and vaping nicotine by age 16 among youth above the poverty line. Also, blunted sadness and happiness reactivity to stress was associated with use of marijuana and alcohol among female adolescents. Blunted stress responses may be a risk factor for substance use among youth above the poverty line and female adolescents.

A Prospective Biopsychosocial Repeated Measures Study of Stress and Dropout from Substance Addiction Treatment

Introduction

This prospective, repeated-measures observational study tested biopsychosocial variables as risk factors for dropping out of inpatient substance addiction treatment. Substance use disorder (SUD) is viewed as a chronic relapsing disease caused by an interaction between biological, psychological, and social factors. However, there is a lack of prospective studies that combine biopsychosocial variables when assessing dropout. The aims of this study were to investigate whether there was 1) An association between biopsychosocial factors and dropping out of inpatient substance addiction treatment, 2) An interaction with SUD diagnosis and cortisol, and 3) Different dropout rates between short-term and long-term institutions.

Materials and Methods

Patients (n = 173) were recruited from two inpatient treatment centers in Norway between 2018 and 2021. The following biopsychosocial variables were measured at four timepoints: ward atmosphere (Ward Atmosphere Scale, WAS), psychological distress (Hopkins Symptom Checklist 10, HSCL-10), motivation (M-scale of the Circumstances, Motivation, Readiness, and Suitability questionnaire), and concentration of salivary cortisol (CORT- nmol/L). Cortisol levels were measured for two consecutive days at each timepoint and calculated by two cortisol indices, daytime cortisol slope (DCS) and area under the curve with respect to the ground (AUC_G). A multivariate logistic regression analysis was performed to find an association between dropout rates and the biopsychosocial variables.

Results

The results suggest a lower dropout odds for patients with high motivation (OR = 0.76, p = 0.022) and patients admitted to short-term treatment (OR = 0.06, p = 0.005). An interaction with stimulant SUD and DCS (OR = 13.74, p = 0.024) also revealed higher dropout odds. No statistical significance was found for psychological distress, WAS, and cortisol AUC_G.

Conclusion

The results support monitoring motivation during treatment and further investigating biopsychosocial variables when assessing dropout risk together with SUD diagnosis.

Cortisol and development of depression in adolescence and young adulthood - a systematic review and meta-analysis

INTRODUCTION

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the development of major depressive disorder (MDD) in adulthood. Less work has focused on the role of the HPA axis in depression in adolescence and young adulthood globally. The aim of this study was to conduct a systematic review and meta-analysis of worldwide research investigating the relationship between cortisol, a measure of HPA axis activity, and MDD in adolescence and young adulthood.

METHOD

We searched MEDLINE, PsycINFO, Cochrane Database of Systematic Reviews, Web of Science, Lilacs, African Journals Online, and Global Health for studies which examined the relationship between cortisol and MDD in global youth (10-24 years old).

RESULTS

Twenty-six studies were included in the systematic review and 14 were eligible for the meta-analysis, but only one study included young adults in their sample. Results from the meta-analysis demonstrated that elevated morning, but not evening, cortisol levels was prospectively associated with later MDD development in adolescence and young adulthood. However, morning cortisol levels did not significantly differ between healthy controls and individuals with MDD in cross-sectional studies. Afternoon cortisol and cortisol stress response also did not differ between adolescents with MDD and healthy controls. Qualitative synthesis of the three studies examining nocturnal cortisol showed higher nocturnal cortisol was both longitudinally and cross-sectionally associated with MDD in adolescence.

CONCLUSION

Our findings suggest elevated morning cortisol precedes depression in adolescence. Despite this, we did not find any differences in other cortisol measures in association with MDD in cross-sectional studies. Taken together, these findings suggest that elevated morning and nocturnal cortisol are risk factors for depression in adolescence rather than a biomarker of existing MDD. This supports a role for the hyperactivity of the HPA axis in the development of MDD in adolescence. Most of the studies were from high-income-countries (HICs) and thus further work would need to be conducted in low- and middle-income countries (LMICs) to understand if our findings are generalisable also to these populations.

Regulatory effects and potential therapeutic implications of alarin in depression, and arguments on its receptor

Alarin is a pleiotropic peptide involved in a multitude of putative biological activities, notably, it has a regulatory effect on depression-like behaviors. Although further elucidating research is needed, animal-based cumulative evidence has shown the antidepressant-like effects of alarin. In light of its regulatory role in depression, alarin could be used as a promising antidepressant in future treatment for depression. Nevertheless, the available information is still insufficient and the therapeutic relevance of alarin in depression is still of concern. Moreover, a plethora of studies have reported that the actions of alarin, including antidepressant activities, are mediated by a separate yet unidentified receptor, highlighting the need for more extensive research. This review focuses on the current understanding of the regulatory effects and future therapeutic relevance of alarin on depression, and the arguments on its receptors.

In(s) and out(s) of adolescent depression - Trajectories of development and recovery

While the role of biological markers in understanding major depressive disorder (MDD) in adults have been studied extensively, less has been done to identify the biomarkers of MDD development and recovery in adolescence. With the majority of mental health disorders starting in adolescence, identifying biomarkers of transition and recovery from MDD early in life is critical for developing effective prevention strategies. Considering most of the child and adolescent populations come from low-and-middle-income countries (LMICs), it is vital to focus on adolescent populations in these settings. With most studies coming from high-income countries (HICs), evidence suggests that elevated morning cortisol levels including cortisol awakening response (CAR), increased peripheral inflammation and brain abnormalities such as cortico-limbic dysregulation or blunted activity in reward related regions in response to positive information are associated with MDD and being at-risk for MDD development in adolescence. We also find that some of the biological mechanisms of recovery from MDD, mainly normalisation in the cortico-limbic dysregulation, are reported following psychological therapy, suggesting shared pathways leading to MDD vulnerability and recovery. Although, only a few studies include adolescent populations. Understanding molecular mechanisms through which psychological interventions are effective, as well as molecular markers of transition to depression in individuals at-risk, are important to inform effective prevention and intervention strategies.

An exploratory study of clinical and physiological correlates of problematic social media use in adolescents

Prior validation studies of the Bergen Social Media Addiction Scale (BSMAS) demonstrate its utility for identifying problematic social media use in adolescents. There are knowledge gaps regarding the potential clinical and physiological underpinnings of problematic social media use in adolescents. This cross-sectional, single-visit study examined a sample of depressed (n = 30) and healthy (n = 30) adolescents who underwent clinical assessments of depressive symptom severity, bullying, cyberbullying, self-esteem, salivary measures of stress (cortisol and α-amylase) to identify correlates with adolescent and parental reports of the BSMAS. LASSO-penalized multiple linear regression models were implemented. With respect to the adolescent BSMAS scores in all subjects, the risk of problematic social media increased as depressive symptom severity increased. Depressed female adolescents appeared to have a greater risk. Based on parental BSMAS scores, depression status, depressive symptom severity, cyberbullying score, and salivary cortisol significantly predicted problematic social media use. For the depressed sample, the risk of problematic social media use increased as salivary cortisol increased. No significant predictors of problematic social media usage emerged in the healthy control sample. These preliminary results provide novel insights into clinical and physiological characteristics of problematic social media use in adolescents.

Undergraduate health profession students attitudes toward illicit substance users in Jordan

BACKGROUND

The use of illicit substances is a critical international issue that must be addressed by healthcare systems worldwide. Today, the problem of illicit substance use is increasingly becoming a burden on healthcare systems in both developed and developing countries. The aims of this study were: (1) to describe the attitudes of health major undergraduate students (the study participants) toward illicit substance users; (2) to describe the discriminatory behaviors among the study participants toward illicit substance users; and (3) to examine the relationship between the attitudes and the actual discriminatory behaviors of the study participants.

METHOD

A cross-sectional descriptive design was used to investigate the attitudes and behaviors of health professional undergraduate students enrolled at university in Jordan.

RESULTS

Students who were younger and identified as female were generally more positive toward illicit substance users versus those students who were older and identified as male.

CONCLUSION

The findings of this study supported the literature that students who were younger and identified as female were generally more positive toward illicit substance users versus those students who were older and identified as male. It is therefore important to determine whether the type of courses in health majors available for undergraduate students affects their attitudes toward illicit substance users.

Altered markers of stress in depressed adolescents after acute social media use

Social media use (SMU) is an inherent element in the daily life and neurodevelopment of adolescents, but broad concerns exist regarding the untoward effects of social media on adolescents. We conducted a prospective, cross-sectional study that sought to examine the acute effects of SMU on clinical measures and biomarkers of stress in healthy and depressed adolescents. After at least 24 h of abstinence from social media, depressed adolescents (n = 30) and healthy control adolescents (n = 30) underwent baseline clinical assessment of their prior SMU, depressive symptom severity, self-esteem, and exposure to bullying. Participants provided salivary samples that were analyzed for α-amylase and cortisol levels. After 20 min of unsupervised SMU, saliva analyses and clinical assessments were repeated. After 20 min of SMU, salivary cortisol and α-amylase levels were significantly higher in adolescents with depression but not in healthy control adolescents. Furthermore, small but statistically significant changes in depressive symptom severity occurred in all participants. These changes in depressive symptoms were not clinically meaningful. SMU did not significantly change self-esteem measures among participants. Adolescents with depression appeared to have more physiological reactivity after SMU compared with healthy adolescents. Further research should characterize SMU as a clinical dimension and risk factor among adolescents with depression and other psychiatric disorders.

Exposure to police-related deaths and physiological stress among urban black youth

BACKGROUND

Emerging evidence indicates that exposure to police-related deaths is associated with negative health and wellbeing outcomes among black people. Yet, no study to date has directly examined the biological consequences of exposure to police-related deaths for urban black youth.

METHODS AND FINDINGS

We employ unique data from the 2014-16 Adolescent Health and Development in Context (AHDC) study - a representative sample of youth ages 11 to 17 residing in the Columbus, OH area. A subsample of participants contributed nightly saliva samples for cortisol for up to six days, providing an opportunity to link recent exposures to police-related deaths within the residential county to physiological stress outcomes during the study period (N = 585). We examine the effect of exposure to a recent police-related death in the same county on the physiological stress (nightly cortisol) levels of black youth. We find evidence of elevated average levels of nightly cortisol (by 46%) for black boys exposed to a police-related death of a black victim in the 30 days prior to the subject's cortisol collection. We find no evidence of police-related death effects on the physiological stress levels of black girls or white youth.

CONCLUSIONS

These analyses indicate that police-related deaths influence the biological functioning of black boys, with potential negative consequences for health. We consider the implications of exposure to lethal police violence among black boys for understanding racial disparities in health more broadly.

The Relationship Between Inflammation and Post-traumatic Stress Disorder

Background: Stress disorders, such as post-traumatic stress disorder (PTSD), are attracting much attention. However, the relationship between traumatic stress and inflammation is rarely discussed. Subjects and Methods: As studies have linked PTSD to altered susceptibility to various diseases, such a psychiatric condition may lead to long-term systematic changes in physiological functions. We searched PubMed with the keywords "traumatic stress," "stress disorders," "post-traumatic stress disorder," and "inflammation." Results: Based on 65 previously published studies, we reviewed the long-term effects of PTSD, as well as traumatic events, on inflammatory function from both epidemiological and biological perspectives. Post-traumatic stress disorder is related to the immune response, including an increase in inflammatory factors and a reduction in anti-inflammatory factors. Additionally, it has been demonstrated that traumatic stress disorder and immune disease share a common genetic basis at the gene expression level. Conclusions: Understanding this relationship is of great significance for optimizing treatment plans for patients with PTSD.

Depression and substance use disorders: Clinical comorbidity and shared neurobiology

Mood disorders, including major depressive disorder (MDD), are the most prevalent psychiatric illnesses, and pose an incredible burden to society, both in terms of disability and in terms of costs associated with medical care and lost work time. MDD has extremely high rates of comorbidity with substance use disorders (SUD) as many of the same neurobiological circuits and molecular mechanisms regulate the reward pathways disrupted in both conditions. MDD may induce SUDs, SUD may contribute to MDD development, or underlying vulnerabilities and common life experience may confer risk to developing both conditions. In this chapter we explore theories of MDD and SUD comorbidity, the neurobiological underpinnings of depression, overlapping cellular and molecular pathways for both conditions, and current treatment approaches for these comorbid conditions.

FKBP5-associated miRNA signature as a putative biomarker for PTSD in recently traumatized individuals

The epigenetic regulation of microRNA (miRNA) expression related to the FK506-binding protein 5 (FKBP5) gene may contribute to the risk of stress-related disorders such as posttraumatic stress disorder (PTSD). Here, we identified candidate miRNAs derived from FKBP5 knockout mice as a potential diagnostic biomarker of PTSD. Using a translational approach, candidate miRNAs found to alter in expression within the medial prefrontal cortex of FKBP5 knockout mice were selected. Each candidate miRNA was examined in the serum of 48 recently traumatized individuals with PTSD and 47 healthy individuals. Multimodal imaging was also conducted to identify the neural correlates for the expression of candidate exosomal miRNAs in response to trauma exposure. Differential miRNA expression was found according to PTSD diagnosis in two composite marker groups. The differential miRNA expression between the composite marker groups contributed to PTSD symptom severity, which may be explained by differential recruitment of prefrontolimbic activity in brain imaging. The present study reveals that a set of circulating exosomal miRNAs showing altered expression in FKBP5 knockout mice play a potential role as epigenetic markers of PTSD. The corroborative evidence from multiple levels including molecular, brain, and behavioral indicates that these epigenetic biomarkers may serve as complementary measures for the diagnosis and prognosis prediction of PTSD in recently traumatized individuals.

Recent/Childhood Adversities and Mental Disorders Among US Immigrants

Past research documents the heterogeneity in US immigrants, particularly in terms of racial and ethnic categories and specific ethnic subgroups. The present study builds on this research foundation by investigating heterogeneity in immigrants' experiences of adversity, both recent and during childhood, and associations with mental disorders. Data are drawn from 6,131 adult immigrants in the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III. Prevalence estimates for mental disorders and adversities were calculated overall and by gender. Latent class analysis was utilized to characterize patterns of self-reported experiences of childhood and recent adversities, and multinomial logistic regression established the statistical association between latent class membership and past-year mental disorder outcomes (substance use disorder only, mood/anxiety/trauma disorder only, co-occurring disorder, or no mental disorder). Neglect was the most commonly-reported childhood adversity among immigrant men and women. Prevalence of meeting criteria for a substance use disorder only, or a mood/anxiety/trauma disorder only, varied between men and women, yet no gender differences were observed in prevalence of co-occurring disorders. For latent class analyses, a five-class solution was selected based on fit indices and parsimony. Approximately 10.0% of the sample was categorized in the latent class characterized by severe childhood adversities, while 57.5% was classified in the latent class with low probabilities of reported adversities. The relative risk of meeting criteria for a past-year substance use disorder only (compared to no substance use or mood/anxiety/trauma disorder) was more than three times as high for members of the class with severe childhood adversities (RRR, 3.26; 95% CI, 2.08-5.10), as well as the class with recent employment/financial adversities (RRR, 3.82; 95% CI, 2.36-6.19), compared to the class with low adversities. The relative risk of past-year co-occurring disorders (compared to no disorder) was more than 12 times as high for those in the severe childhood adversities class (RRR, 12.21; 95% CI, 7.06-21.10), compared to the class with low adversities. Findings underscore the importance of considering both recent and childhood adversities when assessing and providing services for US immigrant groups.

Comparing Mental Health across Distinct Groups of Users of Psychedelics, MDMA, Psychostimulants, and Cannabis

Differences in mental health (MH) of users of distinct psychoactive substances have been shown. Both substance use (SU) and MH in users are influenced by stressful life events. This study compared MH parameters in distinct groups of substance users and evaluated the impact of stress factors on these outcomes. Data stem from the longitudinal Swiss Cohort Study on Substance Use Risk Factors (C-SURF) involving 4,475 young adult men. Distinct groups were created for the past 12 months' use of psychedelics, MDMA, psychostimulants, and cannabis. MH measurements (depressive symptoms, overall MH, perceived stress, life satisfaction) were used as outcome variables, while indicators of past family functioning and stressful life events served as covariates. The MH of psychedelics users was not significantly different from the no-drug-use group, whereas poorer MH was found in the other SU groups. Observed effects were influenced by the tested stress factors. The absence of association between use of psychedelics and worsening of MH deserves further investigation in male and female samples. Stressful life experiences must be considered when assessing the MH of users of illicit substances. These findings suggest that some men practice SU as self-medication to cope with life adversity.

Pathways Relating the Neurobiology of Attachment to Drug Addiction

Substance use disorders constitute a significant public health problem in North America and worldwide. Specifically, substance addictions in women during pregnancy or in the postpartum period have adverse effects not only on the mother, but also on mother-infant attachment and the child's subsequent development. Additionally, there is growing evidence suggesting that parental addiction may be transmitted intergenerationally, where the child of parents with addiction problems is more likely to experience addiction as an adult. The current review takes a developmental perspective and draws from animal and human studies to examine how compromised early experience, including insecure attachment, early abuse/neglect, and unresolved trauma, may influence the development of neurobiological pathways associated with addictions, ultimately increasing one's susceptibility to addictions later in life. We approach this from three different levels: molecular, neuroendocrine and behavioral; and examine the oxytocin affiliation system, dopamine reward system, and glucocorticoid stress response system in this regard. Increased understanding of these underlying mechanisms may help identify key targets for early prevention efforts and inform needed intervention strategies related to both insecure attachment and addiction.

Adrenocortical sensitivity, moderated by ongoing stress, predicts drinking intensity in alcohol-dependent men

Allostatic load from both environmental stressors and persistent glucocorticoid secretion has been associated with disease severity in alcohol dependence. Heightened relapse risk and/or drinking severity, in particular, may be a reaction to alcohol- and withdrawal-induced changes in physiological stress response systems coupled with ongoing life stress, although their shared contributions upon drinking severity have not been assessed. To investigate the combined contribution of hypothalamic-pituitary-adrenal (HPA) reactivity and environmental stressors (e.g., ongoing life stress) to relapse severity in alcohol-dependent men following treatment, plasma adrenocorticotropin (ACTH) and cortisol were obtained in 4-6 weeks abstinent alcohol-dependent men (n=41) following a psychosocial stressor [the Trier Social Stress Test (TSST)] and two pharmacological provocations [ovine corticotropin releasing factor (oCRH) and cosyntropin]. Following treatment discharge, drinking outcomes (primary outcome: drinks per drinking day (DDD); secondary outcomes: total drinks and drinking days) were assessed weekly and ongoing life stress was assessed biweekly for 24 weeks following treatment discharge. Generalized estimating equation models of drinking severity were fit with basal and stimulated ACTH and cortisol concentrations as predictors and ongoing life stress as the moderator. Greater levels of life stress were independently associated with greater drinking intensity (DDD and total drinks) but not frequency (days drinking). Higher basal cortisol:ACTH or provoked cortisol:ACTH ratios were strongly associated with greater post-treatment DDD in individuals who experienced higher levels of ongoing stress. In conclusion, ongoing life stress is associated with post-treatment drinking intensity in alcohol dependent men; stress also strengthens the relationship between adrenocortical sensitivity and post-treatment drinking. Physiological measures of allostatic load and environmental stressors conjointly increase relapse intensity.

Past racial discrimination exacerbates the effects of racial exclusion on negative affect, perceived control, and alcohol-risk cognitions among Black young adults

Racial discrimination is associated with alcohol use and risky sex cognitions and behaviors, which are risk factors for negative health outcomes, including human immunodeficiency virus infection. The current study investigated the causal impact of racial discrimination on alcohol and sexual-risk cognitions while exploring potential mediators that might help explain this relation: negative affect, perceived control, and meaningful existence. We also examined if past discrimination impacts the strength of (moderates) these effects. Participants were 287 Black/African American young adults aged 18-25. They were randomly assigned to be excluded or included by White peers via the game Cyberball. Racial exclusion (vs. inclusion) predicted greater: perceived racial discrimination, negative affect, alcohol use willingness, and reduced perceived control and meaningful existence. Furthermore, excluded participants who experienced more past racial discrimination reported the lowest perceived control, and greatest negative affect and alcohol-risk cognitions. The findings suggest that past racial discrimination exacerbates the harmful health effects of immediate experiences of discrimination.

Early adverse experience and substance addiction: dopamine, oxytocin, and glucocorticoid pathways

Substance addiction may follow a chronic, relapsing course and critically undermine the physical and psychological well-being of the affected individual and the social units of which the individual is a member. Despite the public health burden associated with substance addiction, treatment options remain suboptimal, with relapses often seen. The present review synthesizes growing insights from animal and human research to shed light upon developmental and neurobiological pathways that may increase susceptibility to addiction. We examine the dopamine system, the oxytocin system, and the glucocorticoid system, as they are particularly relevant to substance addiction. Our aim is to delineate how early adverse experience may induce long-lasting alterations in each of these systems at molecular, neuroendocrine, and behavioral levels and ultimately lead to heightened vulnerability to substance addiction. We further discuss how substance addiction in adulthood may increase the risk of suboptimal caregiving for the next generation, perpetuating the intergenerational cycle of early adverse experiences and addiction.

Annual Research Review: On the developmental neuropsychology of substance use disorders

BACKGROUND

Adolescence represents a period of development during which critical biological, as well as social and cognitive, changes occur that are necessary for the transition into adulthood. A number of researchers have suggested that the pattern of normative brain changes that occurs during this period not only predisposes adolescents to engage in risk behaviours, such as experimentation with drugs, but that they additionally make the adolescent brain more vulnerable to the direct pharmacological impact of substances of abuse. The neural circuits that we examine in this review involve cortico-basal-ganglia/limbic networks implicated in the processing of rewards, emotion regulation, and the control of behaviour, emotion and cognition.

FINDINGS AND CONCLUSIONS

We identify certain neurocognitive and personality/comorbidity-based risk factors for the onset of substance misuse during adolescence, and summarise the evidence suggesting that these risk factors may be further impacted by the direct effect of drugs on the underlying neural circuits implicated in substance misuse vulnerability.

Alcohol use and depression during adolescence and young adulthood: a summary and interpretation of mixed findings

Alcohol Use Disorder (AUD) and alcohol misuse are common among adolescents and young adults and are associated with significant personal and societal problems. Similarly, Major Depressive Disorder (MDD) and depressive symptoms are prevalent in this population and when they co-occur with alcohol misuse lead to even more severe consequences. Numerous studies have investigated the association between depressive symptoms, AUD and various drinking behaviors presenting an unclear picture. In this review we summarize studies among adolescents and young adults that have examined these relationships. From this review it emerges that several factors affect results, including study design (cross-sectional vs longitudinal), participants' age (adolescents vs young adults), severity of problems considered (AUD vs heavy drinking; MDD vs depressive symptoms), and gender. Adolescents with AUD are at higher risk for MDD in particular at a younger age. During adolescence, several drinking behaviors, including weekly alcohol use and heavy drinking, increase the risk for depressive symptoms and MDD, while during young adulthood primarily AUD, but not other drinking behaviors, is associated with increased risk for MDD. Gender may have an effect on the association between depression and drinking behaviors but its role is still unclear. Some evidence suggests that the association between AUD and MDD is bidirectional such that mood problems contribute to the onset of alcohol problems and vice-versa. More longitudinal studies are needed to examine these associations in young adults and to clarify the effect of gender on these associations. To date, findings suggest the critical need to reduce any alcohol use at a young age and to treat both depressive symptoms and AUD to prevent the occurrence of comorbid disorders.

Individual, school-related and family characteristics distinguish co-occurrence of drinking and depressive symptoms in very young adolescents

INTRODUCTION AND AIMS

Alcohol misuse and depressed mood are common during early adolescence, and comorbidity of these conditions in adulthood is associated with poorer health and social outcomes, yet little research has examined the co-occurrence of these problems at early adolescence. This study assessed risky and protective characteristics of pre-teens with concurrent depressed mood/early alcohol use in a large school-based sample.

DESIGN AND METHODS

School children aged 10-14 years (n = 7289) from late primary and early secondary school classes in government, Catholic and independent sectors participated with parental consent in the cross-sectional Healthy Neighbourhoods Study. Key measures included depressed mood, recent alcohol use, school mobility, family relationship quality, school engagement and coping style. Multinomial logistic regression analyses were used to identify school and family-related factors that distinguished those with co-occurring drinking and depressive symptoms from those with either single condition. Gender and school-level interactions for each factor were evaluated.

RESULTS

Co-occurring conditions were reported by 5.7% of students [confidence interval (CI)95 5.19, 6.19]. Recent drinkers were more likely than non-drinkers to have symptoms consistent with depression (odds ratio 1.80; CI95 1.58, 2.03). Low school commitment was associated with co-occurring drinking/depressive symptoms (odds ratio 2.86; CI95 2.25, 3.65 compared with null condition). This association appeared to be weaker in the presence of adaptive stress-coping skills (odds ratio 0.18; CI95 0.14, 0.23).

CONCLUSIONS

We have identified factors that distinguish pre-teens with very early co-occurrence of drinking and depressed mood, and protective factors with potential utility for school-based prevention programmes targeting these conditions. [Salom CL, Kelly AB, Alati R, Williams GM, Patton GC, Williams JW. Individual, school-related and family characteristics distinguish co-occurrence of drinking and depressive symptoms in very young adolescents. Drug Alcohol Rev 2016;35:387-396].

Biomarkers of intergenerational risk for depression: a review of mechanisms in longitudinal high-risk (LHR) studies

BACKGROUND

Longitudinal research is critical for understanding the biological mechanisms underlying the development of depression. Researchers recruit high-risk cohorts to understand how risk is transmitted from one generation to the next. Biological measurements have been incorporated into these longitudinal high-risk (LHR) studies in order to illuminate mechanistic pathways.

METHODS

To frame our review, we first present heritability estimates along the gene-by-environment continuum as a foundation. We then offer a Biomarkers of Intergenerational Risk for Depression (BIRD) model to describe the multiple hits individuals at risk receive and to allow for greater focus on the interactive effects of markers. BIRD allows for the known multifinality of pathways towards depression and considers the context (i.e., environment) in which these mechanisms emerge. Next, we review the extant LHR cohort studies that have assessed central nervous system (electroencephalography (EEG), neuroimaging), endocrine (hypothalamic-pituitary-adrenal axis (HPA)/cortisol), autonomic (startle, heart rate), genetic, sleep, and birth characteristics.

RESULTS

Results to date, in conjunction with the proposed model, point towards several pathways of discovery in understanding mechanisms, providing clear direction for future research examining potential endophenotypes.

LIMITATIONS

Our review is based on relatively narrow inclusion and exclusion criteria. As such, many interesting studies were excluded, but this weakness is offset by strengths such as the increased reliability of findings.

CONCLUSIONS

Blanket prevention programs are inefficient and plagued by low effect sizes due to low rates of actual conversion to disorder. The inclusion of biomarkers of risk may lead to enhanced program efficiency by targeting those at greatest risk.

Prenatal cocaine exposure differentially affects stress responses in girls and boys: associations with future substance use

Prenatal cocaine exposure may affect developing stress response systems in youth, potentially creating risk for substance use in adolescence. Further, pathways from prenatal risk to future substance use may differ for girls versus boys. The present longitudinal study examined multiple biobehavioral measures, including heart rate, blood pressure, emotion, and salivary cortisol and salivary alpha amylase (sAA), in response to a stressor in 193 low-income 14- to 17-year-olds, half of whom were prenatally cocaine exposed (PCE). Youth's lifetime substance use was assessed with self-report, interview, and urine toxicology/breathalyzer at Time 1 and at Time 2 (6-12 months later). PCE × Gender interactions were found predicting anxiety, anger, and sadness responses to the stressor, with PCE girls showing heightened responses as compared to PCE boys on these indicators. Stress Response × Gender interactions were found predicting Time 2 substance use in youth (controlling for Time 1 use) for sAA and sadness; for girls, heightened sadness responses predicted substance use, but for boys, dampened sAA responses predicted substance use. Findings suggest distinct biobehavioral stress response risk profiles for boys and girls, with heightened arousal for girls and blunted arousal for boys associated with prenatal risk and future substance use outcomes.

Towards a unitary perspective between post-traumatic stress disorder and substance use disorder. Heroin use disorder as case study

BACKGROUND

Genetic, neurobiological, environmental and psychosocial mechanisms have received considerable attention in exploring the mechanisms that underlie comorbid PTSD and SUD. PTSD and SUD are not necessarily linked by a causal relationship, as the self-medication hypothesis had supposed. They might, in fact, both be caused by a third factor that predisposes these subjects to develop the two disorders (so allowing a unitary perspective).

METHODS

Using a conceptualization of the PTSD spectrum, we studied the PTSD-SUD unitary perspective by testing the correlation between severity of heroin addiction, dose of opioid medication and severity of PTSD spectrum in 82 methadone-treated, heroin-dependent patients.

RESULTS

Canonical correlation analysis (Wilks Lambda=0.125F=1.41 p=0.014), univariate and multivariate comparisons between subgroups, identified on the basis of addiction severity, showed a highly positive correlation between the PTSD spectrum and the severity of heroin addiction. In addition, negative correlations were found between PTSD spectrum severity and methadone dose (r=0.225; p=0.042).

CONCLUSIONS

This strength and breadth of the correlations encourage us to move towards a unified vision of the two disorders.

Alarin-induced antidepressant-like effects and their relationship with hypothalamus-pituitary-adrenal axis activity and brain derived neurotrophic factor levels in mice

Alarin is a newly identified member of the galanin family of peptides. Galanin has been shown to exert regulatory effects on depression. Similar to galanin in distribution, alarin is also expressed in the medial amygdala and hypothalamus, i.e., regions interrelated with depression. However, it remains a puzzle whether alarin is involved in depression. Accordingly, we established the depression-like mouse model using behavioral tests to ascertain the possible involvement of alarin, with fluoxetine as a positive control. With the positive antidepressant-like effects of alarin, we further examined its relationship to HPA axis activity and brain-derived neurotrophic factor (BDNF) levels in different brain areas in a chronic unpredictable mild stress (CUMS) paradigm. In the acute studies, alarin produced a dose-related reduction in the immobility duration in tail suspension test (TST) in mice. In the open-field test, intracerebroventricular (i.c.v.) injection of alarin (1.0 nmol) did not impair locomotion or motor coordination in the treated mice. In the CUMS paradigm, alarin administration (1.0 nmol, i.c.v.) significantly improved murine behaviors (FST and locomotor activity), which was associated with a decrease in corticotropin-releasing hormone (CRH) mRNA levels in the hypothalamus, as well as a decline in serum levels of CRH, adrenocorticotropic hormone (ACTH) and corticosterone (CORT), all of which are key hormones of the HPA axis. Furthermore, alarin upregulated BDNF mRNA levels in the prefrontal cortex and hippocampus. These findings suggest that alarin may potentiate the development of new antidepressants, which would be further secured with the identification of its receptor(s).

Dysregulated responses to emotions among abstinent heroin users: correlation with childhood neglect and addiction severity

The aim of this paper was to investigate the subjective responses of abstinent heroin users to both neutral and negative stimuli and the related hypothalamus-pituitary-adrenal reactions to emotional experience in relationship to their perception of childhood adverse experiences. Thirty male abstinent heroin dependents were included in the study. Emotional responses and childhood neglect perception were measured utilizing the State-Trait Anxiety Inventory Y-1 and the Child Experience of Care and Abuse Questionnaire. Neutral and unpleasant pictures selected from the International Affective Picture System and the Self-Assessment Manikin procedure have been used to determine ratings of pleasure and arousal. These ratings were compared with normative values obtained from healthy volunteers used as control. Blood samples were collected before and after the experimental sessions to determine both adrenocorticotropic hormone and cortisol plasma levels. Basal anxiety scores, cortisol and adrenocorticotropic hormone levels were higher in abstinent heroin users than in controls. Tests showed that anxiety scores did not change in controls after the vision of neutral slides, whilst they did in abstinent heroin addicts, increasing significantly; and increased less significantly after the unpleasant task, in comparison to controls. Abstinent heroin users showed significantly higher levels of parent antipathy and childhood emotional neglect perception than controls for both the father and the mother. Plasma adrenocorticotropic hormone and cortisol levels did not significantly increase after unpleasant slide set viewing among addicted individuals, because of the significantly higher basal levels characterizing the addicted subjects in comparison with controls. Multiple regression correlation showed a significant relationship between childhood neglect perception, arousal reaction, impaired hypothalamus-pituitary-adrenal axis response and addiction severity. Early adverse experiences seem to affect the entire interaction between hyper-arousal, reduced hormonal response to stress and addiction severity. Our findings, although obtained in a small number of subjects, indicate a significant link between the perception of parental style/care/support during childhood and the ability to cope with stressful emotional stimuli in adulthood and addiction severity.

Predictors of first-onset substance use disorders during the prospective course of bipolar spectrum disorders in adolescents

OBJECTIVE

Substance use disorders (SUD) are common and problematic in bipolar disorder (BP). We prospectively examined predictors of first-onset SUD among adolescents with BP.

METHOD

Adolescents (12-17 years old; N = 167) in the Course and Outcome of Bipolar Youth (COBY) study fulfilling criteria for BP-I, BP-II, or operationalized BP not otherwise specified, without SUD at intake, were included. Baseline demographic, clinical, and family history variables, and clinical variables assessed during follow-up, were examined in relation to first-onset SUD. Participants were prospectively interviewed every 38.5 ± 22.2 weeks for an average of 4.25 ± 2.11 years.

RESULTS

First-onset SUD developed among 32% of subjects, after a mean of 2.7 ± 2.0 years from intake. Lifetime alcohol experimentation at intake most robustly predicted first-onset SUD. Lifetime oppositional defiant disorder and panic disorder, family history of SUD, low family cohesiveness, and absence of antidepressant treatment at intake were also associated with increased risk of SUD, whereas BP subtype was not. Risk of SUD increased with increasing number of these 6 predictors: 54.7% of subjects with 3 or more predictors developed SUD vs. 14.1% of those with fewer than 3 predictors (hazard ratio = 5.41 95% confidence interval = 2.7-11.0 p < .0001). Greater hypo/manic symptom severity in the preceding 12 weeks predicted greater likelihood of SUD onset. Lithium exposure in the preceding 12 weeks predicted lower likelihood of SUD.

CONCLUSIONS

This study identifies several predictors of first-onset SUD in the COBY sample that, if replicated, may suggest targets for preventive interventions for SUD among youth with BP. Treatment-related findings are inconclusive and must be interpreted tentatively, given the limitations of observational naturalistic treatment data. There is a substantial window of opportunity between BP and SUD onset during which preventive strategies may be used.

The relation of substance use with different levels of depressive symptoms and the moderating effect of sex and age in Taiwanese adolescents

BACKGROUND

The aim of this cross-sectional study was to examine (a) the relation of substance use with different levels of depressive symptoms and (b) the moderating effect of sex and age on the association between different levels of depressive symptoms and substance use in Taiwanese adolescents.

METHODS

The study group consisted of 9070 adolescent students in southern Taiwan aged 12 to 19 years who were sorted into 3 different levels of depressive symptoms on the Center for Epidemiologic Studies Depression Scale. The Questionnaire for Experience in Substance Use was used to assess each participant's experience with smoking, alcohol consumption, betel nut chewing, sedative/hypnotic use, and illicit drug use in the preceding year. The rates of substance use were compared among adolescents with different levels of depressive symptoms using generalized linear mixed-model analysis. The moderating effects of sex and age on the association between different levels of depressive symptoms and substance use were also examined.

RESULTS

Adolescents with severe depressive symptoms had higher rates of using all 5 kinds of substances than did nondepressed ones. Adolescents with minor depressive symptoms had higher rates of using all substances except for illicit drugs than did nondepressed ones. There was no significant difference in the rates of substance use between adolescents with severe and minor depressive symptoms. Sex and age had no moderating effect on the association between the level of depressive symptoms and substance use.

CONCLUSIONS

It is necessary to carefully screen substance use among adolescents with depressive symptoms, even if they are below the threshold for significant depression.

Depression symptoms associated with cannabis dependence in an adolescent American Indian community sample

BACKGROUND

Depression and substance use disorders, including cannabis dependence, arise during adolescence, are frequently comorbid, and represent major health burdens in the general US population. Yet little is known about the association of depression symptoms with cannabis and other substance use and use disorders in Native American adolescents.

OBJECTIVE

To investigate the comorbidity of cannabis use and depression symptoms in Native American adolescents.

METHODS

This study used the Children's Semi-Structured Assessment for the Genetics of Alcoholism (Adolescent Version) to obtain lifetime DSM-III-R diagnoses from a community sample of 202 (98 boys, 104 girls) American Indian adolescents living on contiguous reservations.

RESULTS

Thirteen percent of boys and 38% of girls had a lifetime DSM-III-R major depression disorder (MDD) independent of substance use. Fifteen percent of boys and 41% of girls had a major depression episode (MDE) either coincident with or independent of cannabis use. MDE and several individual depression symptoms were significantly associated with cannabis dependence in boys but not in girls. The median ages of onset of MDE were the same in the boys and girls who had experienced both depression and cannabis use.

CONCLUSIONS

These findings suggest that the association of depression with cannabis dependence is more significant in boys than girls in this population of adolescents.

SCIENTIFIC SIGNIFICANCE

Understanding comorbidity between depression and cannabis use is important in order to disentangle the etiological relationship between the two and also for designing more effective treatment and prevention strategies, particularly in Native Americans who are at high risk for both disorders.

Gray matter differences between healthy and depressed adolescents: a voxel-based morphometry study

BACKGROUND

Major depressive disorder (MDD) frequently begins during adolescence and is associated with significant morbidity and mortality. However, little is known about the neurobiology of adolescent depression. A better understanding of the neurobiology will be helpful in developing more effective preventive and treatment interventions for this highly disabling illness.

METHODS

Using a voxel-based morphometric method, the study compared gray matter and white matter volumes in 22 adolescents with MDD and 22 age- and gender-matched normal controls.

RESULTS

Compared with controls, depressed adolescents had smaller gray matter volume in the frontal lobe and caudate nucleus bilaterally and right superior and middle temporal gyri. However, the groups did not differ significantly on white matter volume.

CONCLUSIONS

These findings in depressed adolescents are consistent with the previous findings of gray matter abnormalities in frontolimbic areas and the striatum in depressed adults and suggest the presence of these structural changes at the onset of depressive illness.

The impact of diacetylmorphine on hypothalamic-pituitary-adrenal axis activity and heroin craving in heroin dependence

BACKGROUND/AIM

Heroin dependence is a chronic relapsing disorder characterized by the compulsion to seek and use heroin. Stress and craving are seen as key factors for heroin use. Moreover, altered hypothalamic-pituitary-adrenal (HPA) axis function has been frequently reported. However, the acute effects of diacetylmorphine (DAM) on HPA axis activity and craving have not been investigated in a controlled study. The present randomized controlled study examined whether DAM administration differs from placebo (saline) administration with regard to HPA axis response and heroin craving.

METHODS

In a crossover experiment, 28 DAM-maintained heroin-dependent patients were first injected with DAM and then saline, or the converse. Plasma adrenocorticotropic hormone (ACTH) and cortisol in saliva and serum were measured at baseline and 20 and 60 min after both injections. Heroin craving was measured at baseline and 60 min after both injections, by means of the Heroin Craving Questionnaire.

RESULTS

Compared to saline, DAM administration induced a significant decrease in plasma ACTH (p < 0.01), serum cortisol (p < 0.0001) and saliva cortisol (p < 0.01), as well as in craving (p < 0.0001), over time.

CONCLUSION

Since acute DAM administration suppresses the stress response, DAM-assisted treatment may be an effective alternative to methadone maintenance in stress-sensitive heroin-dependent patients.

The limbic-hypothalamic-pituitary-adrenal axis and the development of alcohol use disorders in youth

OBJECTIVE

As the initiation and acceleration of alcohol use commonly occurs during adolescence, the etiological basis for this phenomenon is of critical importance. Using the diathesis-stress model as a framework, this review will evaluate the emerging evidence implicating the limbic-hypothalamic-pituitary-adrenal (LHPA) axis in the development of alcohol use disorder (AUD).

METHOD

Searches were conducted of the PubMed/Medline, PsycInfo, PsycBooks, Cochrane and ISI Web of Science databases, using a specified set of search terms.

RESULTS

Genetic liabilities, antenatal stress/anxiety or exposure to addictive substances, exposure to maltreatment or other traumatic events in childhood and psychiatric illness in childhood/adolescence can all increase the risk, or diathesis, for AUD. Greater LHPA dysfunction may serve as a marker for higher diathesis levels in youth. When exposed to stressors in adolescence, high-risk youth (or those with greater LHPA dysfunction) may use alcohol and/or other substances to cope with stressors and, in turn, become more vulnerable to AUD.

CONCLUSION

Evidence suggests that LHPA dysfunction and stress play an important role in the development of AUD. Genetic liabilities, antenatal insults, maltreatment, and psychiatric illness appear to increase LHPA dysfunction, raising risk for AUD. Further research is needed to clarify the complex interplay among adverse developmental experiences, LHPA dysfunction, and the development of AUD in adolescents.

Longitudinal course of adolescent depression: neuroendocrine and psychosocial predictors

OBJECTIVE

The study examined whether cortisol measures are associated with the clinical course of depression in adolescents. Furthermore, the study evaluated whether the relationship between cortisol and clinical course is moderated by environmental stress and/or social support.

METHOD

Fifty-five adolescents with depression (age range 13-18 years) were recruited. In addition to a systematic diagnostic assessment, information was obtained on environmental stress and social support. Urinary free cortisol measures were collected on three consecutive nights during the index episode. Clinical follow-up evaluations were conducted at regular intervals over a 5-year period, documenting recovery from the index depressive episode and recurrent episodes. Information on environmental stress and social support also was gathered during each follow-up assessment.

RESULTS

Consistent with prior reports, the majority of adolescents (92.2%) recovered from the initial depressive episode. A substantial proportion of the recovered youth (42.6%) experienced a subsequent episode during the follow-up period. Higher cortisol levels were associated with a longer time to recovery from the index depressive episode. The effect of cortisol on recovery was moderated by social support. The combination of elevated cortisol and recent stressful experiences predicted recurrence, whereas a higher level of social support was protective against recurrence.

CONCLUSIONS

These data, in conjunction with prior literature, suggest that depression reflects an underlying neurobiological vulnerability that may predispose individuals with high vulnerability to chronic, recurrent episodes. Psychosocial factors, independently or in combination with an underlying neurobiological vulnerability, also play an important role in determining the clinical course of depression.

COMORBIDITY BETWEEN DEPRESSIVE AND ADDICTIVE DISORDERS IN ADOLESCENTS: ROLE OF STRESS AND HPA ACTIVITY

Adolescents are at heightened risk for the development of both depressive and addictive disorders. These two disorders frequently co-occur in adolescents and are associated with significant morbidity and mortality. Given the substantial economic and psychosocial burden associated with the comorbid condition, the identification of causal mechanisms associated with their co-occurrence is of great public health importance. Evidence indicates that psychosocial stress contributes to the initiation and maintenance of both depressive and addictive disorders. Research suggests that the limbic-hypothalamic-pituitary-adrenal (LHPA) axis also may be important in the development of depression as well as addictive disorders. Using a diathesis-stress model, this review will examine the interactions between stressful experiences and LHPA axis in increasing the risk for depressive and addictive disorders in adolescents. Emerging evidence suggests that the high rates of comorbidity between these two disorders may be explained, in part, by high levels of stress and altered LHPA activity. Clinical implications of these associations will be discussed.

Contribution of hypothalamic-pituitary-adrenal activity and environmental stress to vulnerability for smoking in adolescents

Although tobacco smoking, which has been linked to depression, is a major public health problem, little is known about the neurobiological factors that confer vulnerability to smoking in youngsters and the effects of adolescent smoking on the course of depression. This study examined whether hypothalamic-pituitary-adrenal (HPA) activity and stressful life experiences are related to smoking behavior in depressed and non-depressed adolescents, and whether smoking predicts a worsening course of depression. Smoking history and stressful experiences were assessed in 151 adolescents (48 with no personal or family history of psychiatric disorder, 48 with no psychiatric history, but at high risk for depression by virtue of parental depression, and 55 with current major depressive disorder). Evening salivary cortisol and nocturnal urinary-free cortisol were measured for three consecutive evenings. The participants were then followed at regular intervals for up to 5 years to assess smoking history, clinical course of depression and stressful experiences during the follow-up period. Increased evening/night-time cortisol levels were associated with both initiation and persistence of smoking during follow-up. Stressful life experiences further increased the risk for smoking in depressed as well as non-depressed youth. Smoking was also associated with a higher frequency of depressive episodes during follow-up. A model that included stressful experiences and cortisol levels reduced the contribution of smoking per se to depression. High evening/night-time cortisol level appears to be a vulnerability marker for smoking in adolescents, with stressful experiences further increasing the risk for smoking in vulnerable youth. High evening/night-time cortisol levels and stressful experiences accounted, at least partially, for the association between depressive illness and smoking behavior.