Influence of the serotonin transporter gene polymorphism, cannabis and childhood sexual abuse on phenotype of bipolar disorder: a preliminary study

Biobehavioral Interactions between Endocannabinoid and Hypothalamicpituitary- adrenal Systems in Psychosis: A Systematic Review

BACKGROUND

The diathesis-stress paradigm and the cannabinoid-hypothesis have been proposed as possible pathophysiological models of schizophrenia. However, they have historically been studied independently of each other.

OBJECTIVE

This PRISMA 2020-compliant systematic review aimed at reappraising the interplay between the hypothalamic-pituitary-adrenal (HPA) axis and the endocannabinoid (eCB) system in psychosis- spectrum disorder risk and outcome.

METHODS

All pathophysiological and outcome clinical studies, concomitantly evaluating the two systems in psychosis-spectrum disorder risk and different stages of illness, were gathered from electronic databases (Pubmed, Web of Science, and Scopus), and discussed.

RESULTS

41 eligible outputs were extracted, focusing on at least a biological measure (9 HPA-related studies: 4 eCB-interventional, 1 HPA-interventional, 1 both HPA-interventional and non-interventional, 3 non-interventional; 2 eCB-related studies: non-interventional), environmental measures only (29 studies: 1 eCB- interventional, 28 non-interventional), and genetic measures (1 study: non-interventional). Independent contributions of aberrancies in the two systems to the physiopathology and outcome of psychosis were confirmed. Also, concomitant alterations in the two systems, either genetically defined (e.g., CNR1 genetic variation), biologically determined (e.g., dysfunctional HPA axis or endocannabinoid signaling), or behaviorally imputed (e.g., cannabis use, stress exposure, and response), were consistently reported in psychosis. Further, a complex biobehavioral perturbation was revealed not only within each system (e.g., cannabis use affecting the eCB tone, stress exposure affecting the HPA axis), but also across the two systems (e.g., THC affecting the HPA axis, childhood trauma affecting the endocannabinoid signaling).

CONCLUSION

There is a need to concomitantly study the two systems' mechanistic contribution to psychosis in order to establish more refined biological relevance.

Circulating miRNAs as Potential Biomarkers for Patient Stratification in Bipolar Disorder: A Combined Review and Data Mining Approach

Bipolar disorder is a debilitating psychiatric condition that is shaped in a concerted interplay between hereditary and triggering risk factors. Profound depression and mania define the disorder, but high clinical heterogeneity among patients complicates diagnosis as well as pharmacological intervention. Identification of peripheral biomarkers that capture the genomic response to the exposome may thus progress the development of personalized treatment. MicroRNAs (miRNAs) play a prominent role in of post-transcriptional gene regulation in the context of brain development and mental health. They are coordinately modulated by multifarious effectors, and alteration in their expression profile has been reported in a variety of psychiatric conditions. Intriguingly, miRNAs can be released from CNS cells and enter circulatory bio-fluids where they remain remarkably stable. Hence, peripheral circulatory miRNAs may act as bio-indicators for the combination of genetic risk, environmental exposure, and/or treatment response. Here we provide a comprehensive literature search and data mining approach that summarize current experimental evidence supporting the applicability of miRNAs for patient stratification in bipolar disorder.

Associations between cannabis use, cannabis use disorder, and mood disorders: longitudinal, genetic, and neurocognitive evidence

RATIONALE

Cannabis use among people with mood disorders increased in recent years. While comorbidity between cannabis use, cannabis use disorder (CUD), and mood disorders is high, the underlying mechanisms remain unclear.

OBJECTIVES

We aimed to evaluate (1) the epidemiological evidence for an association between cannabis use, CUD, and mood disorders; (2) prospective longitudinal, genetic, and neurocognitive evidence of underlying mechanisms; and (3) prognosis and treatment options for individuals with CUD and mood disorders.

METHODS

Narrative review of existing literature is identified through PubMed searches, reviews, and meta-analyses. Evidence was reviewed separately for depression, bipolar disorder, and suicide.

RESULTS

Current evidence is limited and mixed but suggestive of a bidirectional relationship between cannabis use, CUD, and the onset of depression. The evidence more consistently points to cannabis use preceding onset of bipolar disorder. Shared neurocognitive mechanisms and underlying genetic and environmental risk factors appear to explain part of the association. However, cannabis use itself may also influence the development of mood disorders, while others may initiate cannabis use to self-medicate symptoms. Comorbid cannabis use and CUD are associated with worse prognosis for depression and bipolar disorder including increased suicidal behaviors. Evidence for targeted treatments is limited.

CONCLUSIONS

The current evidence base is limited by the lack of well-controlled prospective longitudinal studies and clinical studies including comorbid individuals. Future studies in humans examining the causal pathways and potential mechanisms of the association between cannabis use, CUD, and mood disorder comorbidity are crucial for optimizing harm reduction and treatment strategies.

Childhood Maltreatment in Bipolar Disorders

In this chapter, we will focus on childhood maltreatment and its role in the vulnerability to BD.We will review how childhood maltreatment and trauma not only predispose to the development of BD but also to a more unstable, pernicious, and severe clinical expression of the disorder. This environmental risk factor is suggested to be part of a multiple hit model of vulnerability, involving not only early stressors (prenatal and postnatal ones) but also interactions with the genetic background of individuals and with other stressors occurring later in life. We will also review how childhood maltreatment and trauma may modify the brain functioning and circuits and alter some biological pathways in BD, hence leading to psychopathology. Finally, we will briefly discuss the implications for clinical practice and treatment.

The role of CACNA1C gene and childhood trauma interaction on bipolar disorder

Studies on gene x environment interaction (GxE) have provided vital information for uncovering the origins of complex diseases. When considering the etiology of bipolar disorder (BD), the role of such interactions is unknown. Here, we tested whether trauma during childhood could modify the effect of two polymorphisms in the CACNA1C gene (rs1006737 and rs4765913) in terms of susceptibility to BD. The study enrolled 878 Caucasian young adults in a cross-sectional population-based survey. BD diagnosis was performed using a clinical interview MINI 5.0, and trauma was assessed with the childhood trauma questionnaire (CTQ). Binary logistic regression models were employed to test the main effects of polymorphisms, haplotypes, and GxE interactions using sex as a confounder. We did not observe an association between the polymorphisms and diagnosis of BD. However, we noted that childhood trauma modified the effect of the rs4765913 polymorphism (p = .018) and the AA haplotype (rs1006737 - rs4765913) (p = .018) on BD susceptibility. A allele carriers of the rs4765913 polymorphism or the AA haplotype exposed to childhood trauma are more likely to develop BD compared to the individuals without a genetic risk. Thus, this study showed that the risk of developing BD in individuals exposed to childhood trauma was influenced by the individual's genetic background, varying according to the CACNA1C genotypes.

Epidemiology and risk factors for bipolar disorder

Bipolar disorder is a multifactorial illness with uncertain aetiology. Knowledge of potential risk factors enables clinicians to identify patients who are more likely to develop bipolar disorder, which directs further investigation, follow up and caution when prescribing. Ideally, identifying directly causative factors for bipolar disorder would enable intervention on an individual or population level to prevent the development of the illness, and improve outcomes through earlier treatment. This article reviews the epidemiology of bipolar disorder, along with putative demographic, genetic and environmental risk factors, while assessing the strength of these associations and to what extent they might be said to be 'causative'. While numerous genetic and environmental risk factors have been identified, the attributable risk of individual factors is often small, and most are not specific to bipolar disorder but are associated with several mental illnesses. Therefore, while some genetic and environmental factors have strong evidence supporting their association with bipolar disorder, fewer have sufficient evidence to establish causality. There is increasing interest in the role of specific gene-environment interactions, as well as the mechanisms by which risk factors interact to lead to bipolar disorder.

Interactions Between Variation in Candidate Genes and Environmental Factors in the Etiology of Schizophrenia and Bipolar Disorder: a Systematic Review

Schizophrenia and bipolar disorder (BD) are complex and multidimensional disorders with high heritability rates. The contribution of genetic factors to the etiology of these disorders is increasingly being recognized as the action of multiple risk variants with small effect sizes, which might explain only a minor part of susceptibility. On the other site, numerous environmental factors have been found to play an important role in their causality. Therefore, in recent years, several studies focused on gene × environment interactions that are believed to bridge the gap between genetic underpinnings and environmental insults. In this article, we performed a systematic review of studies investigating gene × environment interactions in BD and schizophrenia spectrum phenotypes. In the majority of studies from this field, interacting effects of variation in genes encoding catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF), and FK506-binding protein 5 (FKBP5) have been explored. Almost consistently, these studies revealed that polymorphisms in COMT, BDNF, and FKBP5 genes might interact with early life stress and cannabis abuse or dependence, influencing various outcomes of schizophrenia spectrum disorders and BD. Other interactions still require further replication in larger clinical and non-clinical samples. In addition, future studies should address the direction of causality and potential mechanisms of the relationship between gene × environment interactions and various categories of outcomes in schizophrenia and BD.

Revisiting the association between childhood trauma and psychosis in bipolar disorder: A quasi-dimensional path-analysis

BACKGROUND

Childhood trauma has been associated with a more severe clinical expression of bipolar disorder (BD). However, the results that specifically associated traumatic events and psychotic features in BD have been inconsistent, possibly due to the low resolution of the phenotypes being used.

METHODS

270 normothymic patients with BD completed the Childhood Trauma Questionnaire (CTQ) and the Peters Delusion Inventory (PDI) that assessed 21 delusional beliefs. Patients were characterized for the lifetime presence of psychotic features during episodes and cannabis misuse in accordance with DSM-IV. We performed a series of path analyses to investigate the links from three types of childhood abuse (physical, sexual and emotional) directly to delusional beliefs and psychotic features, and indirectly through cannabis misuse.

RESULTS

A first path analysis showed no link between any of the childhood abuse types and psychotic features when only a categorical definition of psychosis was used. When incorporating the quasi-dimensional measure of delusional beliefs in a second path analysis, we found that emotional and physical abuse and cannabis misuse were each directly associated with PDI score. PDI score and psychotic features were strongly correlated. Childhood abuse did not operate through cannabis misuse to increase delusional beliefs. Including type of BD in the model did not alter the results.

CONCLUSION

Emotional and physical abuse, but also cannabis misuse, increased delusional beliefs in patients with BD. Using a quasi-dimensional measure of psychotic symptoms in BD provided higher resolution of the psychosis phenotype and helped reconcile ambiguous findings from previous studies.

Childhood trauma and treatment outcome in bipolar disorder

The aim of the present study was to investigate the potential influence of childhood trauma on clinical presentation, psychiatric comorbidity, and long-term treatment outcome of bipolar disorder. A total of 135 consecutive patients with bipolar disorder type I were recruited from an ongoing prospective follow-up project. The Childhood Trauma Questionnaire and the Structured Clinical Interview for DSM-IV Axis I Disorders were administered to all participants. Response to long-term treatment was determined from the records of life charts of the prospective follow-up project. There were no significant differences in childhood trauma scores between groups with good and poor responses to long-term lithium treatment. Poor responders to long-term anticonvulsant treatment, however, had elevated emotional and physical abuse scores. Lifetime diagnosis of posttraumatic stress disorder (PTSD) was associated with poor response to lithium treatment and antidepressant use but not with response to treatment with anticonvulsants. Total childhood trauma scores were related to the total number of lifetime comorbid psychiatric disorders, antidepressant use, and the presence of psychotic features. There were significant correlations between all types of childhood abuse and the total number of lifetime comorbid psychiatric diagnoses. Whereas physical neglect was related to the mean severity of the mood episodes and psychotic features, emotional neglect was related to suicide attempts. A history of childhood trauma or PTSD may be a poor prognostic factor in the long-term treatment of bipolar disorder. Whereas abusive experiences in childhood seem to lead to nosological fragmentation (comorbidity), childhood neglect tends to contribute to the severity of the mood episodes.

Biological aspects and candidate biomarkers for psychotic bipolar disorder: A systematic review

AIM

We carried out a systematic review of the available literature about potential biomarkers of psychotic bipolar disorder (BD-P), a specific subset presenting worse outcome and greater risk of relapse than non-psychotic bipolar disorder (BD-NP).

METHODS

We searched the main psychiatric databases (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles with the main topic of BD-P compared to schizophrenia/BD-NP/healthy controls (HC) written in English from 1994 to 2015 were included.

RESULTS

BD-P patients presented higher kynurenic acid levels in the cerebrospinal fluid, elevated anti- S accharomyces cerevisiae antibodies levels, and lower serum levels of dehydroepiandrosterone sulfate and progesterone than BD-NP/HC. Event-related potentials abnormalities have been identified in BD-P with respect to BD-NP. BD-P patients also presented bigger ventricles but similar hippocampal volumes compared to BD-NP/HC. Although the results are contrasting, some cognitive deficits seemed to be related to the psychotic dimension of bipolar affective disorder, such as impairment in verbal/logical memory, working memory, verbal and semantic fluency and executive functioning. Finally, polymorphisms of genes, such as NRG1, 5HTTLPR (s), COMT, DAOA and some chromosome regions (16p12 and 13q), were positively associated with BD-P.

CONCLUSION

Data about the identification of specific biomarkers for BD-P are promising, but most of them have not yet been replicated. They could lead the clinicians to an early diagnosis and proper treatment, thus ameliorating outcome of BD-P and reducing the biological changes associated with a long duration of illness. Further studies with bigger samples are needed to detect more specific biological markers of the psychotic dimension of bipolar affective disorder.

Childhood maltreatment and unfavourable clinical outcomes in bipolar disorder: a systematic review and meta-analysis

BACKGROUND

Bipolar disorder affects up to one in 25 individuals and identification of early risk indicators of negative outcomes could facilitate early detection of patients with greatest clinical needs and risk. We aimed to investigate the association between childhood maltreatment and key negative outcomes in patients with bipolar disorder.

METHODS

For this systematic review and meta-analysis we searched MEDLINE, PsycINFO, and Embase to identify articles published before Jan 1, 2015, examining the association of maltreatment (physical, sexual, or emotional abuse, neglect, or family conflict) before age 18 years with clinical features and course of illness in bipolar disorder. Data were extracted from published reports and any missing information was requested from investigators. We did 12 independent random-effects meta-analyses to quantify the associations between childhood maltreatment and course of illness or clinical features.

FINDINGS

We initially identified 527 records and after unsuitable studies were removed, our search yielded 148 publications of which 30 were used in the meta-analysis. Patients with bipolar disorder and history of childhood maltreatment had greater mania severity (six studies, 780 participants; odds ratio [OR] 2·02, 95% CI 1·21-3·39, p=0·008), greater depression severity (eight studies, 1007 participants; 1·57, 1·25-1·99, p=0·0001), greater psychosis severity (seven studies, 1494 participants; 1·49, 1·10-2·04, p=0·011), higher risk of comorbidity with post-traumatic stress disorder (eight studies, 2494 participants; 3·60, 2·45-5·30, p<0·0001), anxiety disorders (seven studies, 5091 participants; 1·90, 1·39-2·61, p<0·0001), substance misuse disorders (11 studies, 5469 participants; 1·84, 1·41-2·39, p<0·0001), alcohol misuse disorder (eight studies, 5040 participants; 1·44, 1·13-1·83, p=0·003), earlier age of bipolar disorder onset (14 studies, 5733 participants; 1·85, 1·43-2·40, p<0·0001), higher risk of rapid cycling (eight studies, 3010 participants; 1·89, 1·45-2·48, p<0·0001), greater number of manic episodes (seven studies, 3909 participants; 1·26, 1·09-1·47, p=0·003), greater number of depressive episodes (eight studies, 4025 participants; 1·38, 1·07-1·79, p=0·013), and higher risk of suicide attempt (13 studies, 3422 participants; 2·25, 1·88-2·70, p<0·0001) compared with those with bipolar disorder without childhood maltreatment. Overall, these associations were not explained by publication bias, undue effects of individual studies, or variation in study quality.

INTERPRETATION

Childhood maltreatment predicts unfavourable clinical features and course of illness in patients with bipolar disorder.

FUNDING

None.

Interaction between SLC6A4 promoter variants and childhood trauma on the age at onset of bipolar disorders

Age at onset (AAO) of bipolar disorders (BD) could be influenced both by a repeat length polymorphism (5HTTLPR) in the promoter region of the serotonin transporter gene (SLC6A4) and exposure to childhood trauma. We assessed 308 euthymic patients with BD for the AAO of their first mood episode and childhood trauma. Patients were genotyped for the 5HTTLPR (long/short variant) and the rs25531. Genotypes were classified on functional significance (LL, LS, SS). A sample of 126 Brazilian euthymic patients with BD was used for replication. In the French sample, the correlation between AAO and trauma score was observed only among 'SS' homozygotes (p = 0.002) but not among 'L' allele carriers. A history of at least one trauma decreased the AAO only in 'SS' homozygotes (p = 0.001). These results remained significant after correction using FDR. Regression models suggested an interaction between emotional neglect and 'SS' genotype on the AAO (p = 0.009) and no further interaction with other trauma subtypes. Partial replication was obtained in the Brazilian sample, showing an interaction between emotional abuse and 'LS' genotype on the AAO (p = 0.02). In conclusion, an effect of childhood trauma on AAO of BD was observed only in patients who carry a specific stress responsiveness-related SLC6A4 promoter genotype.

5-HTTLPR Genotype Moderates the Effects of Past Ecstasy Use on Verbal Memory Performance in Adolescent and Emerging Adults: A Pilot Study

OBJECTIVE

Ecstasy use is associated with memory deficits. Serotonin transporter gene (5-HTTLPR) polymorphisms have been linked with memory function in healthy samples. The present pilot study investigated the influence of 5-HTTLPR polymorphisms on memory performance in ecstasy users, marijuana-using controls, and non-drug-using controls, after a minimum of 7 days of abstinence.

METHOD

Data were collected from 116 young adults (18-25 years-old), including 45 controls, 42 marijuana users, and 29 ecstasy users, and were balanced for 5-HTTLPR genotype. Participants were abstinent seven days prior to completing memory testing. Three MANCOVAs and one ANCOVA were run to examine whether drug group, 5-HTTLPR genotype, and their interactions predicted verbal and visual memory after controlling for gender, past year alcohol use, other drug use, and nicotine cotinine levels.

RESULTS

MANCOVA and ANCOVA analysis revealed a significant interaction between drug group and genotype (p = .03) such that ecstasy users with the L/L genotype performed significantly worse on CVLT-2 total recall (p = .05), short (p = .008) and long delay free recall (p = .01), and recognition (p = .006), with the reverse pattern found in controls. Ecstasy did not significantly predict visual memory. 5-HTTLPR genotype significantly predicted memory for faces (p = .02); short allele carriers performed better than those with L/L genotype.

CONCLUSIONS

5-HTTLPR genotype moderated the effects of ecstasy on verbal memory, with L/L carriers performing worse compared to controls. Future research should continue to examine individual differences in ecstasy's impact on neurocognitive performance as well as relationships with neuronal structure. Additional screening and prevention efforts focused on adolescents and emerging adults are necessary to prevent ecstasy consumption.

Depression with psychotic features is influenced by the polymorphism of the serotonin transporter gene

INTRODUCTION

Current diagnostic classifications regard psychotic symptoms during depressive episodes as indicators of depression severity. However, growing evidence suggests that depression with psychotic symptoms (MDP) may represent a distinct subtype of depression. In the course of the search for discriminating factors we tested the hypothesis that the serotonin transporter gene (5-HTTLPR) may interact with the manifestation of psychotic symptoms in acute depression.

METHODS

112 inpatients (61 female) with a depressive episode (16 bipolar, 86 unipolar) at admission were genotyped for 5-HTTLPR variants. Psychotic symptoms und general psychopathology were evaluated comprehensively using the Manual of the Association for Methodology and Documentation in Psychiatry (Arbeitsgemeinschaft für Methodik und Dokumentation in der Psychiatrie, 1981). For statistical analysis a chi-square test and a logistic regression model was used.

RESULTS

16 (14.3%) out of 112 patients were currently presenting with psychotic symptoms. The primary finding of our study was the higher prevalence of the s-allele of the 5-HTTLPR within the group of MDP patients (Pearson χ²=7.87; df=2; p<0.03). Secondly, in a logistic regression model, 5-HTTLPR was found to significantly contribute to the diagnosis of MDP (χ²=6.5; df=1; p=0.01). This effect was even more pronounced upon comparing only severely depressed patients with MDP patients. From a psychopathological perspective, MDP patients showed higher AMDP hostility and apathy scores but equal AMDP depression scores.

DISCUSSION

This is the first study to show an influence of 5-HTTLPR on psychotic symptoms in acutely depressed patients.

LIMITATIONS

The lack of a control group and the relatively small sample size limits the present study's findings, thus replication in a larger sample is necessary.

The impact of child sexual abuse on the course of bipolar disorder: a systematic review

OBJECTIVES

The aim of this review was to elucidate the impact of child sexual abuse on all clinical phenomena that occur after the onset of bipolar disorder, including associated clinical features that are not part of the diagnostic criteria for the disorder.

METHODS

Five databases were searched and supplemented with a hand search of reference lists from retrieved papers. Study quality was assessed using a validated quality assessment tool. Blind assessments of study eligibility and quality were conducted by two independent researchers to reduce bias, minimize errors, and enhance the reliability of findings. Disagreements were resolved by consensus.

RESULTS

Eighteen studies that included a total of 2996 adults and youths with bipolar disorder and met the minimum quality criteria necessary to ensure objectivity and not invalidate results were analyzed. Across studies, child sexual abuse was strongly (and perhaps directly) associated with posttraumatic stress disorder; whereas it was less strongly (and perhaps indirectly) related to suicide attempts, alcohol and/or drug abuse or dependence, psychotic symptoms, and an early age of illness onset. In regard to the association between child sexual abuse and other clinical variables concerning the course of bipolar disorder, evidence was scant or conflicting.

CONCLUSIONS

Child sexual abuse is associated (either directly or indirectly) with some clinical phenomena that represent a more severe form of bipolar disorder. Although such a traumatic experience may directly affect the development of posttraumatic stress disorder, the effects of early sexual abuse on later suicidal behavior, substance abuse, and psychotic symptoms may operate through the mediating influences of certain psychopathological or neurobiological variables.

Prevalence of child sexual abuse among adults and youths with bipolar disorder: a systematic review

To estimate the prevalence and social and demographic correlates of child sexual abuse among people with bipolar disorder, the findings of all the pertinent studies were qualitatively and semi-quantitatively analyzed. Five databases were searched. Blind assessments of study eligibility and quality were conducted by two independent researchers. Twenty studies, meeting minimum quality standards and including 3407 adults and youths with bipolar disorder across 10 countries and 3 continents, were examined. The prevalence of child sexual abuse was 24% (23% without outliers); however, such prevalence rate might be underestimated, because many studies restricted definitions to the most severe forms of abuse. Child sexual abuse was a common experience for both males and females, while it was more frequent for adults than for youths. Compared to healthy individuals, patients with bipolar disorder reported higher rates of child sexual abuse; compared to populations with other mental disorders, participants with bipolar disorder reported similar or lower rates of such abuse. Individuals with bipolar disorder are at risk of having a history of child sexual abuse, although such risk seems to be neither more specific to nor stronger for these individuals, compared to people with other psychiatric disorders.

Genome-wide significant association between a 'negative mood delusions' dimension in bipolar disorder and genetic variation on chromosome 3q26.1

Research suggests that clinical symptom dimensions may be more useful in delineating the genetics of bipolar disorder (BD) than standard diagnostic models. To date, no study has applied this concept to data from genome-wide association studies (GWAS). We performed a GWAS of factor dimensions in 927 clinically well-characterized BD patients of German ancestry. Rs9875793, which is located in an intergenic region of 3q26.1 and in the vicinity of the solute carrier family 2 (facilitated glucose transporter), member 2 gene (SLC2A2), was significantly associated with the factor analysis-derived dimension 'negative mood delusions' (n=927; P=4.65 × 10(-8), odds ratio (OR)=2.66). This dimension was comprised of the symptoms delusions of poverty, delusions of guilt and nihilistic delusions. In case-control analyses, significant association with the G allele of rs9875793 was only observed in the subgroup of BD patients who displayed symptoms of 'negative mood delusions' (allelic χ(2) model: P(G)=0.0001, OR=1.92; item present, n=89). Further support for the hypothesis that rs9875793 is associated with BD in patients displaying 'negative mood delusions' symptom, such as delusions of guilt, was obtained from an European American sample (GAIN/TGEN), which included 1247 BD patients and 1434 controls (P(EA)=0.028, OR=1.27).

Voices from the storm: a critical review of quantitative studies of auditory verbal hallucinations and childhood sexual abuse

Although an association between hallucinations and sexual abuse has been documented, the relation between specifically auditory verbal hallucinations (AVHs) and childhood sexual abuse (CSA) is less clear. This study reviewed quantitative studies of AVHs and CSA. 36% of psychiatric patients with AVHs, and 22% of non-psychiatric patients with AVHs, reported CSA. At least 16% of the general population with auditory hallucinations also reported CSA. The majority of studies reviewed found that those with AVHs were more likely to be survivors of CSA than individuals without AVHs. 56% of psychiatric patients with CSA reported AVHs, and at least 21% of the general population with CSA reported auditory hallucinations. A majority of studies found survivors of CSA were more likely to report AVHs than individuals without CSA. Ability to impute a causal role for CSA was impaired by such studies' failures to control for potentially confounding variables. Yet, studies of AVH content showed links between the content of voices and the content of CSA in some voice-hearers. It is concluded that although a clear association between CSA and AVHs exists, there is not yet reliable quantitative evidence of a causal relation. Implications for mental health professionals and for future research, are discussed.