Specificity of familial vulnerability for alcoholism versus major depression in men

Psychiatric comorbidities in alcohol use disorder

Alcohol use disorder is a major contributor to the morbidity and mortality burden worldwide. It often coexists with other psychiatric disorders; however, the nature of this comorbidity is still a matter of debate. In this Series paper, we examine the main psychiatric disorders associated with alcohol use disorder, including the prevalence of co-occurring disorders, the temporal nature of the relationship, and mechanisms that might explain comorbidity across the lifespan. Overall, this disorder co-occurs with a wide range of other psychiatric disorders, especially those disorders involving substance use and violent or aggressive behaviour. The causal pathways between alcohol use disorder and other psychiatric disorders are heterogeneous. Hypotheses explaining these relationships include reciprocal direct causal associations, shared genetic and environmental causes, and shared psychopathological characteristics of broader diagnostic entities (eg, externalising disorders). Efforts to untangle the associations between alcohol use disorder and other disorders across the lifespan remain a crucial avenue of research.

Alcohol consumption predicts incidence of depressive episodes across 10 years among older adults in 19 countries

Alcohol consumption is increasing in many countries, and excessive alcohol consumption is particularly increasing among older adults. Excessive alcohol consumption causes morbidity and mortality, especially among older adults, including an increased risk of depressive episodes. We review the mechanisms through which alcohol consumption may affect depression, and argue that the effects of alcohol consumption on depressive episodes among older adults are understudied. We harmonized data among older adults (≥50 years) on alcohol consumption, depressive episodes, and an array of risk factors across 10 years and 19 countries (N=57,276). Alcohol consumption was categorized as current or long-term abstainer, occasional, moderate and heavy drinking at an average of 2.3 follow-up time points. Depressive episodes were measured through the CES-D or EURO-D. Multi-level Cox proportional frailty models in which the random effect has a multiplicative relationship to hazard were estimated with controls for co-occurring medical conditions, health behaviors, and demographics. Long-term alcohol abstainers had a higher hazard of depressive episodes (HR=1.14, 95% C.I. 1.08-1.21), as did those reporting occasional (HR=1.16, 95% C.I. 1.10-1.21) and heavy drinking (HR=1.22, 95% C.I. 1.13-1.30), compared with moderate drinking. Hazard ratios were attenuated in frailty models; heavy drinking, however, remained robustly associated in a random-effects model with a frailty component (HR=1.16, 95% C.I. 1.11-1.21). Interactions were observed by gender and smoking status: long-term abstainers, women's, and smokers' (HR for interaction, 1.04, 95% C.I. 1.00-1.07) hazards of depressive episodes increased more than what would be expected based on their multiplicative effects, when compared to moderate drinking, non-smoking men. Excessive alcohol consumption among older adults is a concern not only for physical, but also for mental health. Physician efforts to screen older adults for excessive alcohol use is critical for mental health to remain strong in aging populations.

Shared genetic etiology between alcohol dependence and major depressive disorder

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The clinical comorbidity of alcohol dependence (AD) and major depressive disorder (MDD) is well established, whereas genetic factors influencing co-occurrence remain unclear. A recent study using polygenic risk scores (PRS) calculated based on the first-wave Psychiatric Genomics Consortium MDD meta-analysis (PGC-MDD1) suggests a modest shared genetic contribution to MDD and AD. Using a (∼10 fold) larger discovery sample, we calculated PRS based on the second wave (PGC-MDD2) of results, in a severe AD case–control target sample. We found significant associations between AD disease status and MDD-PRS derived from both PGC-MDD2 (most informative P-threshold=1.0, P=0.00063, R²=0.533%) and PGC-MDD1 (P-threshold=0.2, P=0.00014, R²=0.663%) meta-analyses; the larger discovery sample did not yield additional predictive power. In contrast, calculating PRS in a MDD target sample yielded increased power when using PGC-MDD2 (P-threshold=1.0, P=0.000038, R²=1.34%) versus PGC-MDD1 (P-threshold=1.0, P=0.0013, R²=0.81%). Furthermore, when calculating PGC-MDD2 PRS in a subsample of patients with AD recruited explicitly excluding comorbid MDD, significant associations were still found (n=331; P-threshold=1.0, P=0.042, R²=0.398%). Meanwhile, in the subset of patients in which MDD was not the explicit exclusion criteria, PRS predicted more variance (n=999; P-threshold=1.0, P=0.0003, R²=0.693%). Our findings replicate the reported genetic overlap between AD and MDD and also suggest the need for improved, rigorous phenotyping to identify true shared cross-disorder genetic factors. Larger target samples are needed to reduce noise and take advantage of increasing discovery sample size.

Temperament and character profiles associated with depression and treatment response in patients with or without comorbid substance abuse

There is limited knowledge on the relationship between temperament and character profiles and substance abuse comorbidity in depressed patients. We recruited 127 depressed patients without alcohol use problems (non-AUP) and 89 depressed patients with alcohol use problems (AUP). We assessed all patients using the Temperament and Character Inventory (TCI-R) at baseline and after 6 weeks of treatment. Using univariate general linear models (GLMs), we analyzed differences in TCI-R between AUP and non-AUP. GLMs were also used in analyzing the associations between TCI-R changes and antidepressive treatment responses measured with changes in Montgomery Åsberg Depression Rating Scale score (ΔMADRS). Alcohol use explained independently significant proportions of the variation in Novelty Seeking, Self-Directedness, and Persistence. Reward Dependence score change explained 14.1% of the ΔMADRS in AUP, but was non-significant in non-AUP. Character score changes in Self-Directedness and Self-Transcendence explained together 14.1% of ΔMADRS in non-AUP, whereas they were all non-significant in AUP. AUP compared with non-AUP patients had lower Self-Directedness and Persistence and higher Novelty Seeking scores. Detected changes in Reward Dependence and lower Self-Directedness in AUP patients could be reflective of different biological mechanisms associated with depressive symptomatology in alcohol abuse. Changes in character are associated with acute treatment response in non-AUP.

The prevalence and correlates of alcohol use and alcohol use disorders: a population based study in Colombo, Sri Lanka

BACKGROUND

Alcohol use is increasing in non-Western countries. However, the effects of this increase on the prevalence of alcohol use disorders (AUD) remains unknown, particularly in South Asia. This study aimed to estimate the prevalence of alcohol use and AUD in the Colombo District, Sri Lanka. Environmental risk factors and psychiatric correlates were also examined.

METHODS

The Composite International Diagnostic Interview was used to assess alcohol use and psychiatric disorders in a population based sample of 6014 twins and singletons in the Colombo region of Sri Lanka.

RESULTS

Lifetime alcohol use on 12 or more occasions was estimated at 63.1 % (95 % CI: 61.3-64.9) in men and 3.7 % (95 % CI: 3.0-4.3) in women. Prevalence of lifetime alcohol abuse and alcohol dependence in men was 6.2 % (95 % CI: 5.3-7.1) and 4.0 % (95 % CI: 3.3-4.7) respectively. Lower standard of living was independently associated with alcohol use and dependence but not abuse. Significant associations between lifetime AUD and other psychiatric disorders were observed.

CONCLUSIONS

Lower prevalence of alcohol use and AUD was observed compared to Western countries. Prevalence of alcohol use and AUD were higher than previous reports. Socio-demographic and environmental risk factors appear to be similar across cultures as were associations between AUD and other psychiatric disorders.

Does age at onset of first major depressive episode indicate the subtype of major depressive disorder?: the clinical research center for depression study

PURPOSE

The purpose of this study was to evaluate the effects of age at onset of the first major depressive episode on the clinical features of individuals with major depressive disorder (MDD) in a large cohort of Korean depressed patients.

MATERIALS AND METHODS

We recruited 419 MDD patients of age over 18 years from the Clinical Research Center for Depression study in South Korea. At the start of the study, the onset age of the first major depressive episode was self-reported by the subjects. The subjects were divided into four age-at-onset subgroups: childhood and adolescent onset (ages <18), early adult onset (ages 18-44), middle adult onset (ages 45-59), and late onset (ages 60+). Using analysis of covariance (ANCOVA) and ordinal logistic regression analysis with adjusting the effect of age, the relationships between clinical features and age at onset of MDD were evaluated.

RESULTS

There was an apparent, but inconsistent correlation between clinical features and age at onset. Earlier onset MDD was significantly associated with higher proportion of female gender [adjusted odds ratio (AOR)=0.570, p=0.022], more previous suicide attempts (AOR=0.635, p=0.038), greater number of previous depressive episodes (F=3.475, p=0.016) and higher scores on the brief psychiatric rating scale (F=3.254, p=0.022), its negative symptom subscale (F=6.082, p<0.0001), and the alcohol use disorder identification test (F=7.061, p<0.0001).

CONCLUSION

Early age at onset may increase the likelihood of distinguishable MDD subtype, and age at onset of the first major depressive episode is a promising clinical indicator for the clinical presentation, course, and outcome of MDD.

Genome-wide association study of comorbid depressive syndrome and alcohol dependence

OBJECTIVE

Depression and alcohol dependence (AD) are common psychiatric disorders that often co-occur. Both disorders are genetically influenced, with heritability estimates in the range of 35-60%. In addition, evidence from twin studies suggests that AD and depression are genetically correlated. Herein, we report results from a genome-wide association study of a comorbid phenotype, in which cases meet the Diagnostic and Statistical Manual of Mental Disorders-IV symptom threshold for major depressive symptomatology and the Diagnostic and Statistical Manual of Mental Disorders-IV criteria for AD.

METHODS

Samples (N=467 cases and N=407 controls) were of European-American descent and were genotyped using the Illumina Human 1M BeadChip array.

RESULTS

Although no single-nucleotide polymorphism (SNP) meets genome-wide significance criteria, we identified 10 markers with P values less than 1 × 10(-5), seven of which are located in known genes, which have not been previously implicated in either disorder. Genes harboring SNPs yielding P values less than 1 × 10(-5) are functionally enriched for a number of gene ontology categories, notably several related to glutamatergic function. Investigation of expression localization using online resources suggests that these genes are expressed across a variety of tissues, including behaviorally relevant brain regions. Genes that have been previously associated with depression, AD, or other addiction-related phenotypes - such as CDH13, CSMD2, GRID1, and HTR1B - were implicated by nominally significant SNPs. Finally, the degree of overlap of significant SNPs between a comorbid phenotype and an AD-only phenotype is modest.

CONCLUSION

These results underscore the complex genomic influences on psychiatric phenotypes and suggest that a comorbid phenotype is partially influenced by genetic variants that do not affect AD alone.

Admixture analysis of age at onset in major depressive disorder

OBJECTIVES

This study aimed to determine the distributions of the age at onset (AAO) in patients with major depressive disorder (MDD) using admixture analysis and to determine the clinical differences between subgroups with different AAO.

METHODS

Participants were administered the Mini-International Neuropsychiatric Interview to obtain clinical data. Admixture analysis was performed using the STATA module DENORMIX to identify subgroups characterized by differences in AAO.

RESULTS

The best fit model was the three-component model with the following means, standard deviations and proportions: 14.60 (3.75) years (49.1%), 29.15 (6.75) years (34.1%) and 46.96 (6.06) years (16.8%) (χ(2)=3.64, 2 df, P=.162). The three subgroups were divided by AAO of 22 and 40. After controlling for duration of illness, there were no significant differences between the three AAO subgroups in terms of gender and psychiatric family history. However, the early-onset subgroup was significantly more likely to report being single compared to the intermediate- and late-onset groups. The proportion of individuals meeting criteria for lifetime comorbid panic disorders and obsessive-compulsive disorder did not differ significantly between the AAO groups. However, the early-onset group reported a higher incidence of attention-deficit/hyperactivity disorder (5.1% vs. 1.7% and 1.2%, P=.086), although this was not statistically significant.

CONCLUSIONS

Our study identified three characteristically different AAO subgroups in individuals suffering from MDD. The subgroups may reflect different underlying neurobiological mechanisms involved.

Structural models of the comorbidity of internalizing disorders and substance use disorders in a longitudinal birth cohort

PURPOSE

The present study examined the associations between internalizing disorders and substance use disorders using structural equation models to examine the relative contributions of common fixed confounding factors and direct causal pathways, and to determine the direction of causality.

METHODS

Data were gathered during the course of the Christchurch Health and Development Study, a 25-year longitudinal study of a birth cohort of New Zealand children (n = 953). Measures included DSM-IV symptom criteria for major depression, anxiety disorders, alcohol abuse/dependence, nicotine dependence, and illicit drug abuse/dependence, ages 18, 21, and 25.

RESULTS

Structural equation modeling showed that for depression and substance use disorder, the best-fitting model was the one in which the associations were explained by a combination of common fixed factors and direct causal pathways from substance use to depression. A similar pattern emerged for anxiety disorders and (1) nicotine dependence, and (2) illicit drug abuse/dependence. The comorbidity of anxiety disorder and alcohol abuse/dependence was best explained by a model that included common fixed factors and a reciprocal pathway between these disorders. Decomposition of the correlations between internalizing disorders and substance use disorders showed that most of the correlation arose from direct causal pathways between disorders.

CONCLUSIONS

The findings suggest that the comorbidity between internalizing disorders and substance use disorders can be attributed to both common fixed factors and direct causal pathways between substance use disorder and internalizing disorder. The evidence suggests that, in most cases, the most plausible explanation of causality is the one in which substance use disorder increases the risk of internalizing disorder.

Alcohol and depression

AIMS

To examine the literature on the associations between alcohol use disorders (AUD) and major depression (MD), and to evaluate the evidence for the existence of a causal relationship between the disorders.

METHODS

PsycInfo; PubMed; Embase; Scopus; ISI Web of Science database searches for studies pertaining to AUD and MD from the 1980 to the present. Random-effects models were used to derive estimates of the pooled adjusted odds ratios (AOR) for the links between AUD and MD among studies reporting an AOR.

RESULTS

The analysis revealed that the presence of either disorder doubled the risks of the second disorder, with pooled AORs ranging from 2.00 to 2.09. Epidemiological data suggest that the linkages between the disorders cannot be accounted for fully by common factors that influence both AUD and MD, and that the disorders appear to be linked in a causal manner. Further evidence suggests that the most plausible causal association between AUD and MD is one in which AUD increases the risk of MD, rather than vice versa. Potential mechanisms underlying these causal linkages include neurophysiological and metabolic changes resulting from exposure to alcohol. The need for further research examining mechanisms of linkage, gender differences in associations between AUD and MD and classification issues was identified.

CONCLUSIONS

The current state of the literature suggests a causal linkage between alcohol use disorders and major depression, such that increasing involvement with alcohol increases risk of depression. Further research is needed in order to clarify the nature of this causal link, in order to develop effective intervention and treatment approaches.

Early environmental influences contribute to covariation between internalizing symptoms and alcohol intoxication frequency across adolescence

The association between alcohol use and internalizing symptoms during adolescence varies across studies, and the causes underlying this association remain unclear. The current study examines the relationship between symptoms of anxiety and depression and intoxication frequency in a sample of Swedish twins assessed longitudinally from ages 13-14 to 19-20. The objectives of the study were to assess the stability of genetic and environmental influences on each trait across adolescence; to investigate whether these traits share genetic and/or environmental liabilities; and to explore quantitative changes in the shared liability over time. We found that the magnitude of genetic influences on internalizing symptoms remained relatively stable across adolescence, while their impact on intoxication frequency was dynamic. Symptoms of anxiety and depression were influenced by unique environmental factors, while both shared and unique environmental factors influenced intoxication frequency. Genetic and environmental innovation and attenuation were observed for both traits. While no significant genetic correlation was observed between traits, unique environmental factors did contribute to a shared liability. This environmental correlation was positive and moderate (r(E)=0.41) in the early assessment, but decreased and changed direction at later waves (r(E)=-.04 to -.01). The genetic and environmental factors underlying internalizing symptoms and intoxication frequency appear to be developmentally dynamic. Early environmental factors contribute to the association between these traits, but this shared liability diminishes across adolescence.

Depressive symptoms and alcohol use are genetically and environmentally correlated across adolescence

Depressive symptoms and alcohol use are frequently positively associated during adolescence. This study aimed to assess the heritability of each phenotype across adolescence; to assess potential shared liabilities; to examine changes in the nature of shared liabilities across adolescence; and to investigate potential causal relationships between depressive symptoms and alcohol use. We studied a longitudinally assessed sample of adolescent Finnish twins (N = 1,282) to test hypotheses about genetic and environmental influences on these phenotypes within and across ages, using data from assessments at ages 12, 14, and 17.5 years. The heritability of depressive symptoms is consistent across adolescence (~40-50%), with contributions from common and unique environmental factors. The heritability of alcohol use varies across time (a(2) = .25-.44), and age 14 alcohol use is heavily influenced by shared environmental factors. Genetic attenuation and innovation were observed across waves. Modest to moderate genetic (r(A) = .26-.59) and environmental (r(C) = .30-.63) correlations between phenotypes exist at all ages, but decrease over time. Tests for causal relationships between traits differed across ages and sexes. Intrapair MZ difference tests provided evidence for reciprocal causation in girls at ages 14 and 17.5. Formal causal models suggested significant causal relationships between the variables in both boys and girls. The association between depressive symptoms and alcohol use during adolescence is likely due to a combination of shared genetic and environmental influences and causal influences. These influences are also temporally dynamic, complicating efforts to understand factors contributing to the relationship between these outcomes.

Does comorbid substance use disorder impair recovery from major depression with SSRI treatment? An analysis of the STAR*D level one treatment outcomes

Many patients with major depressive disorder (MDD) present with concurrent substance use disorders (SUDs), which has been thought to impair their response to antidepressants. Clinicians often delay antidepressant treatment until sustained sobriety has been established. Unfortunately, these comorbid subjects are typically excluded from depression treatment trials, leaving a gap in understanding the treatment outcomes. In the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, 2876 adult outpatients diagnosed with nonpsychotic MDD were prospectively treated with the selective serotonin-reuptake inhibitor (SSRI), citalopram, and returned for at least one post-baseline visit. Participants with SUD (29%) and without SUD (71%) were compared in regard to baseline clinical and sociodemographic features and treatment response. The group with MDD and SUD was further subdivided into those with alcohol only, drug only, and both alcohol and drug use. Despite clear sociodemographic and clinical differences, there were no significant differences between groups in the time to achieve response or rates of response to citalopram; however, those who endorsed both alcohol and drug use had significantly reduced rates of remission and significantly increased times to reach remission compared to the MDD group without SUD. In addition, subjects with MDD and SUD had higher risk of psychiatric serious adverse events (3.3% vs. 1.5%) and hospitalization (2.8% vs. 1.2%). The results indicate that first-line treatment with citalopram in depressed patients with alcohol or drug use respond as well as those without SUD. More intensive treatment is most likely needed for MDD patients with both drug and alcohol use disorders.

Mood-related drinking motives mediate the familial association between major depression and alcohol dependence

BACKGROUND

Major depression and alcohol dependence co-occur within individuals and families to a higher than expected degree. This study investigated whether mood-related drinking motives mediate the association between major depression and alcohol dependence, and what the genetic and environmental bases are for this relationship.

METHODS

The sample included 5,181 individuals from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, aged 30 and older. Participants completed a clinical interview which assessed lifetime major depression, alcohol dependence, and mood-related drinking motives.

RESULTS

Mood-related drinking motives significantly explained the depression-alcohol dependence relationship at both the phenotypic and familial levels. Results from twin analyses indicated that for both males and females, the familial factors underlying mood-related drinking motives accounted for virtually all of the familial variance that overlaps between depression and alcohol dependence.

CONCLUSIONS

The results are consistent with an indirect role for mood-related drinking motives in the etiology of depression and alcohol dependence, and suggest that mood-related drinking motives may be a useful index of vulnerability for these conditions.

Major depression and comorbid substance use disorders

PURPOSE OF REVIEW

The presentation of major depressive disorder is often complicated by the co-occurrence of substance use disorders, such as alcohol and illicit drug abuse or dependence. The article reviews the recent systematic research on the distinguishing baseline characteristics including demographic characteristics and the influence of family history, and clinical features such as depressive symptomatology and suicidal ideation, and the outcome of treatment for depression in patients with comorbid major depressive disorder and substance use disorders. The review also addresses the possible explanations cited in the literature as to why these two disorders tend to co-occur and the implications of the comorbidity of these illnesses on treatment.

RECENT FINDINGS

Nearly one-third of patients with major depressive disorder also have substance use disorders, and the comorbidity yields higher risk of suicide and greater social and personal impairment as well as other psychiatric conditions. Although the treatment of comorbid major depressive disorder and substance use disorders with medication is likely effective, the differential treatment effects based on substance use disorder comorbidity have been understudied.

SUMMARY

Emerging results of recent studies comparing the outcome of major depressive disorder patients with comorbid major depressive disorder and substance use disorders suggest that there are fewer differential effects based on comorbidity than previously anticipated by older assumptions from smaller, less methodologically rigorous studies.