Influence of childhood maltreatment on prevalence, onset, and persistence of psychiatric comorbidities and suicide attempts in bipolar disorders.

BACKGROUND: Psychiatric comorbidities and suicide attempts are highly prevalent in Bipolar Disorders (BD). We examined the associations between childhood maltreatment, psychiatric comorbidities, and suicide attempts, in terms of lifetime prevalence, sequence of onset, and current symptoms. METHODS: We assessed 3,047 individuals with BD for suicide attempts, anxiety disorders, substance use disorders, and eating disorders. Participants completed a self-report for the assessment of childhood maltreatment. Associations between childhood maltreatment and characteristics of comorbidities (lifetime prevalence, current symptoms, and age at onset) were examined using logistic regressions and network analyses. RESULTS: Psychiatric comorbidities were frequent with a mean number per individual of 1.23 (SD = 1.4). Most comorbidities occurred prior to the onset of BD. Participants who reported higher levels of childhood maltreatment had more frequent and multiple comorbidities, which were also more currently active at inclusion. Childhood maltreatment did not decrease the age of onset of comorbidities, but was associated with a faster accumulation of comorbidities prior to the onset of BD. Logistic regression and network analyses showed that emotional abuse and sexual abuse might play a prominent role in the lifetime prevalence of psychiatric comorbidities and suicide attempts. CONCLUSIONS: Childhood maltreatment was associated with suicide attempts, and with frequent, multiple, and persistent psychiatric comorbidities that accumulated more rapidly prior to the onset of BD. Hence, childhood maltreatment should be systematically assessed in individuals with BD, in particular when the course of the disorder is characterized by a high comorbid profile or by a high suicidality.

Network of co-expressed circadian genes, childhood maltreatment and sleep quality in bipolar disorders.

Bipolar disorder (BD) is a chronic and burdensome psychiatric disease, characterized by variations in mood and energy. The literature has consistently demonstrated an association between BD and childhood maltreatment (CM), and genetic variants of circadian genes have been associated with an increased vulnerability to develop BD. In this context, environmental factors such as CM may also contribute to the susceptibility to BD through alterations in the functioning of the biological clock linked to modifications of expression of circadian genes. In this study, we explored the associations between childhood maltreatment, sleep quality, and the level of expression of a comprehensive set of circadian genes in lymphoblastoid cell lines from patients with BD. The sample consisted of 52 Caucasian euthymic patients with a diagnosis of BD type 1 or type 2. The exposure to CM was assessed with the Childhood Trauma Questionnaire (CTQ), and the sleep quality was assessed using the Pittsburgh Sleep Quality Index. We measured the expression of 18 circadian genes using quantitative RT-PCR: ARNTL2, BHLHE40, BHLHE41, CLOCK, CRY1, CRY2, CSNK1D, CSNK1E, DBP, GSK3B, NPAS2, NR1D1, PER1, PER2, PER3, PPARGC1A, RORA, and RORB. Gene expression networks were analyzed with the disjoint graphs method. Compared to the other investigated transcripts, PPARGC1A was the only one whose expression level was differentially affected in patients who have experienced CM and, more specifically, physical abuse. We observed no significant effects of the other CTQ subscores (emotional and sexual abuses, physical and emotional neglects), nor of the sleep quality on the network of circadian genes expression. Although requiring replication in larger cohorts, the result obtained here is consistent with the hypothesis of an influence of CM exposure on circadian systems and highlights the importance of PPARGC1A in these processes.

Childhood maltreatment and HPA axis gene expression in bipolar disorders: A gene network analysis.

INTRODUCTION: Bipolar disorder (BD) is highly associated with childhood maltreatment (CM), the exposure to such early adversity being suggested to disrupt the expression of several biological pathways. This study aims at exploring associations between the mRNA levels of 9 HPA axis genes in lymphoblastoid cell lines from patients with BD according to their self-reported exposure to CM. METHODS: The sample consisted of 33 Caucasian patients with a diagnosis of BD type 1, assessed for the exposure to CM with the Childhood Trauma Questionnaire (CTQ). Quantitative RT-PCR was performed on 9 transcripts of the HPA axis genes: DGKH, FKBP5, NR3C1, SGK1, SGK2, SGK3, SKA2, STAT5A and UCN. RT-qPCR data were analyzed using the method of disjoint gene networks with SARP.compo package for R. RESULTS: We found no associations between CTQ total score and the amount of HPA axis transcripts neither in univariate analyses, nor with network analyses. Emotional abuse (EA) was associated with a significant decreased expression of two transcripts, DGKH (p = 0.009) and NR3C1 (p = 0.04). This was confirmed by the disjoint network analysis, which showed that NR3C1 and DGKH were expressed differently from the rest of the HPA axis network in presence of emotional abuse. DISCUSSION: This study described the expression levels of a comprehensive set of HPA axis genes according to childhood maltreatment in a sample of patients with BD type 1 and suggested that emotional abuse decreased the expression of NR3C1 and DGKH. Our results require further replication in independent larger samples.