Cortical brain structure and sexual orientation in adult females with bipolar disorder or attention deficit hyperactivity disorder

Refining Research and Representation of Sexual and Gender Diversity in Neuroscience

There are opportunities to improve neuroscience that include lesbian, gay, bisexual, and transgender (LGBT) people. In this review, we briefly describe how the history of LGBT people in psychiatry has influenced neuroimaging approaches; how these attitudes have shifted over time; and what we can do to ensure that our future work is rigorous, ethical, and in service of the LGBT community. We suggest ways to refine neuroimaging methodologies to improve our understanding of marginalization and stigma while shifting away from research that focuses solely on the "etiology" or origins of LGBT identities. We also offer suggestions for conducting representative research that is LGBT-inclusive, regardless of the population of interest.

Medial Prefrontal Cortex Activity to Reward Outcome Moderates the Association Between Victimization Due to Sexual Orientation and Depression in Youth

BACKGROUND

Sexual minority youth (SMY) are 3 times more likely to experience depression than heterosexual peers. Minority stress theory posits that this association is explained by sexual orientation victimization, which acts as a stressor to impact depression. For those vulnerable to the effects of stress, victimization may worsen depression by altering activity in neural reward systems. This study examines whether neural reward systems moderate the influence of sexual orientation victimization, a common and distressing experience in SMY, on depression.

METHODS

A total of 81 participants ages 15 to 22 years (41% SMY, 52% marginalized race) reported sexual orientation victimization, depression severity, and anhedonia severity, and underwent a monetary reward functional magnetic resonance imaging task. Significant activation to reward > neutral outcome (p_{familywise error} < .05) was determined within a meta-analytically derived Neurosynth reward mask. A univariate linear model examined the impact of reward activation and identity on victimization-depression relationships.

RESULTS

SMY reported higher depression (p < .001), anhedonia (p = .03), and orientation victimization (p < .001) than heterosexual youth. The bilateral ventral striatum, medial prefrontal cortex (mPFC), anterior cingulate cortex, and right orbitofrontal cortex were significantly active to reward. mPFC activation moderated associations between sexual orientation victimization and depression (p = .03), with higher depression severity observed in those with a combination of higher mPFC activation and greater orientation victimization.

CONCLUSIONS

Sexual orientation victimization was related to depression but only in the context of higher mPFC activation, a pattern observed in depressed youth. These novel results provide evidence for neural reward sensitivity as a vulnerability factor for depression in SMY, suggesting mechanisms for disparities, and are a first step toward a clinical neuroscience understanding of minority stress in SMY.

Retracted: Sexual orientation, neuropsychiatric disorders and the neurotransmitters involved

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor in Chief of Neuroscience and Biobehavioral Reviews after concerns were raised with respect to the phrasing of comparisons drawn between humans and animal models. These comparisons were deemed unsupportable, and thus in the best interests of publication standards the Editor has concluded it is necessary to retract the paper. The authors disagree with the reason for the retraction.

Brain structure and clinical profile point to neurodevelopmental factors involved in pedophilic disorder

OBJECTIVE

Pedophilic disorder (PD) is characterized bypersistent, intense sexual attraction to prepubertal children that the individual has acted on, or causes marked distress or interpersonal difficulty. Although prior research suggests that PD has neurodevelopmental underpinnings, the evidence remains sparse. To aid the understanding of etiology and treatment development, we quantified neurobiological and clinical correlates of PD.

METHOD

We compared 55 self-referred, help-seeking, non-forensic male patients with DSM-5 PD with 57 age-matched, healthy male controls (HC) on clinical, neuropsychological, and structural brain imaging measures (cortical thickness and surface area, subcortical and white matter volumes). Structural brain measures were related to markers for aberrant neurodevelopment including IQ, and the 2nd to 4th digit ratio (2D:4D).

RESULTS

PD was associated with psychiatric disorder comorbidity and ADHD and autism spectrum disorder symptoms. PD patients had lower total IQ than HC. PD individuals exhibited cortical surface area abnormalities in regions belonging to the brain's default mode network and showed abnormal volume of white matter underlying those regions. PD subjects had smaller hippocampi and nuclei accumbens than HC. Findings were not related to history of child-related sexual offending. IQ correlated negatively with global expression of PD-related brain features and 2D:4D correlated with surface area in PD.

CONCLUSIONS

In the largest single-center study to date, we delineate psychiatric comorbidity, neurobiological and cognitive correlates of PD. Our morphometric findings, their associations with markers of aberrant neurodevelopment, and psychiatric comorbidities suggest that neurodevelopmental mechanisms are involved in PD. The findings may need consideration in future development of clinical management of PD patients.

Cross-sex shifts in two brain imaging phenotypes and their relation to polygenic scores for same-sex sexual behavior: A study of 18,645 individuals from the UK Biobank

Genetic and hormonal factors have been suggested to influence human sexual orientation. Previous studied proposed brain differences related to sexual orientation and that these follow cross-sex shifted patterns. However, the neurobiological correlates of sexual orientation and how genetic factors relate to brain structural variation remains largely unexplored. Using the largest neuroimaging-genetics dataset available on same-sex sexual behavior (SSB) (n = 18,645), we employed a data-driven multivariate classification algorithm (PLS) on magnetic resonance imaging data from two imaging modalities to extract brain covariance patterns related to sex. Through analyses of latent variables, we tested for SSB-related cross-sex shifts in such patterns. Using genotype data, polygenic scores reflecting the genetic predisposition for SSB were computed and tested for associations with neuroimaging outcomes. Patterns important for classifying between males and females were less pronounced in non-heterosexuals. Predominantly in non-heterosexual females, multivariate brain patterns as represented by latent variables were shifted toward the opposite sex. Complementary univariate analyses revealed region specific SSB-related differences in both males and females. Polygenic scores for SSB were associated with volume of lateral occipital and temporo-occipital cortices. The present large-scale study demonstrates multivariate neuroanatomical correlates of SSB, and tentatively suggests that genetic factors related to SSB may contribute to structural variation in certain brain structures. These findings support a neurobiological basis to the differences in human sexuality.

Interactive effects of gender and sexual orientation on cortical thickness, surface area and gray matter volume: a structural brain MRI study

Background

Testosterone is thought to play a crucial role in sexual differentiation of the brain, and sexual orientation is programmed into our brain structures even when we are still fetuses. Although gender and sexual orientation differences have been shown respectively in many brain structures, the mechanism underlying the sexual differentiation of the brain is still unknown. The study is to investigate the interactive effects of gender and sexual orientation on cerebral structures in homosexual and heterosexual people.

Methods

Sexual orientation was evaluated by the Kinsey scale. We collected structural magnetic resonance image (MRI) data of local cortical thickness, surface area, and gray matter volume in all the subjects (29 homosexual and 29 heterosexual men, 17 homosexual and 17 heterosexual women). Statistical maps were generated using a general linear model (GLM) using FreeSurfer's Query, Design, Estimate, Contrast (QDEC) interface. We had sexual orientation and gender as 2 discrete factors with 2 levels, allowing for the generation of the interaction between sexual orientation and gender: homosexual women and heterosexual men versus heterosexual women and homosexual men. Coordinates were in Talairach space. All the cluster sizes were calculated with a P value of 0.01.

Results

Results revealed interactions concerning the area and gray matter volume between the factors of sexual orientation and gender. Regarding the thickness, an interaction was not found in any regions of the clusters. Regarding the area, an interaction was found in region of left middle temporal lobe, inferior temporal lobe, lateral occipital lobe, fusiform [(-58.1, -38.6, -14.7), maximum vertex-wise (MV) log₁₀(P) =3.30, cluster size (CS) =1,286.90 mm²], and left rostral middle frontal lobe, pars opercularis, caudal middle frontal lobe [(-37.3, 23.6, 24.8), MV log₁₀(P) =2.92, CS =1,194.40 mm²]. Regarding the gray matter volume, an interaction was found in the region of the left pars opercularis (inferior frontal gyrus) [(-42.9, 6.3, 18.5), MV log₁₀(P) =1.31, CS =526.79 mm²].

Conclusions

The present study extends our understandings of how structural features differ in homosexual men, heterosexual men, homosexual women, and heterosexual women. Furthermore, it highlights the interactions between sexual orientation and gender in the left inferior frontal gyrus, bilateral temporal lobe, and the right rostral anterior cingulate cortex, which are suggested to play a critical role in the sexual differentiation of the human brain.

Sex differences in stress-related disorders: Major depressive disorder, bipolar disorder, and posttraumatic stress disorder

Stress-related disorders, such as mood disorders and posttraumatic stress disorder (PTSD), are more common in women than in men. This sex difference is at least partly due to the organizing effect of sex steroids during intrauterine development, while activating or inhibiting effects of circulating sex hormones in the postnatal period and adulthood also play a role. Such effects result in structural and functional changes in neuronal networks, neurotransmitters, and neuropeptides, which make the arousal- and stress-related brain systems more vulnerable to environmental stressful events in women. Certain brainstem nuclei, the amygdala, habenula, prefrontal cortex, and hypothalamus are important hubs in the stress-related neuronal network. Various hypothalamic nuclei play a central role in this sexually dimorphic network. This concerns not only the hypothalamus-pituitary-adrenal axis (HPA-axis), which integrates the neuro-endocrine-immune responses to stress, but also other hypothalamic nuclei and systems that play a key role in the symptoms of mood disorders, such as disordered day-night rhythm, lack of reward feelings, disturbed eating and sex, and disturbed cognitive functions. The present chapter focuses on the structural and functional sex differences that are present in the stress-related brain systems in mood disorders and PTSD, placing the HPA-axis in the center. The individual differences in the vulnerability of the discussed systems, caused by genetic and epigenetic developmental factors warrant further research to develop tailor-made therapeutic strategies.

Cortical brain structure and sexual orientation in adult females with bipolar disorder or attention deficit hyperactivity disorder

BACKGROUND

Nonheterosexual individuals have higher risk of psychiatric morbidity. Together with growing evidence for sexual orientation-related brain differences, this raises the concern that sexual orientation may be an important factor to control for in neuroimaging studies of neuropsychiatric disorders.

METHODS

We studied sexual orientation in adult psychiatric patients with bipolar disorder (BD) or ADHD in a large clinical cohort (N = 154). We compared cortical brain structure in exclusively heterosexual women (HEW, n = 29) with that of nonexclusively heterosexual women (nHEW, n = 37) using surface-based reconstruction techniques provided by FreeSurfer.

RESULTS

The prevalence of nonheterosexual sexual orientation was tentatively higher than reported in general population samples. Consistent with previously reported cross-sex shifted brain patterns among homosexual individuals, nHEW patients showed significantly larger cortical volumes than HEW in medial occipital brain regions.

CONCLUSION

We found evidence for a sex-reversed difference in cortical volume among nonheterosexual female patients, which provides insights into the neurobiology of sexual orientation, and may provide the first clues toward a better neurobiological understanding of the association between sexual orientation and mental health. We also suggest that sexual orientation is an important factor to consider in future neuroimaging studies of populations with certain mental health disorders.