The behavioral component of sexual inhibition and its relation with testosterone levels: An fMRI study in transgender and cisgender individuals

Many transgender individuals report having difficulties with initiating and seeking sexual contacts. Relatively to cisgender individuals, transgender individuals are more likely to avoid sexual activity, indicating that the groups might differ in the neural underpinnings of the behavioral component of sexual inhibition. In this fMRI study, transgender (n = 33) and cisgender (n = 34) participants performed an Approach Avoidance Task (AAT) assessing sexual inhibition. We found that over the entire sample, the task elicited brain activation commonly associated with general and sexual inhibition, for instance in the bilateral insula, right inferior parietal lobule, and right inferior and middle frontal gyri. Upon investigating group differences between transgender and cisgender participants, we mainly found similarities in neural activation during the task. However, there were group differences in regions involved in decision making processes (left middle temporal gyrus) and sexual response inhibition (right anterior cingulate cortex and left inferior parietal lobule). In order to investigate whether these group differences were modulated by testosterone levels, we performed ROI-analyses assessing the relationship between testosterone and neural activation during the AAT (controlling for sex assigned at birth), but no correlations were found. On the whole brain level, however, we found that testosterone correlated positively with cerebral activation in the right claustrum (a region associated with sexual arousal) during the approach of sexual stimuli in the transgender group. Overall, these findings indicate that transgender and cisgender individuals mostly show similarities in their neural response to a sexual Approach-Avoidance task, and that testosterone levels are unlikely to play an important role.

The nucleus accumbens dopamine increase, typically triggered by sexual stimuli in male rats, is no longer produced when animals are sexually inhibited due to sexual satiety

RATIONALE

Exposure of male rats to an inaccessible receptive female and copulation increases dopamine (DA) levels in the nucleus accumbens (NAcc). Males copulating to satiety become sexually inhibited and most of them do not display sexual activity when presented with a sexually receptive female 24 h later. This inhibitory state can be pharmacologically reversed. There are no studies exploring NAcc DA levels during this sexual inhibitory state.

OBJECTIVES

To characterize changes in NAcc DA and its metabolites' levels during sexual satiety development, during the well-established sexual inhibitory state 24 h later, and during its pharmacological reversal.

METHODS

Changes in NAcc DA and its metabolites were measured in sexually experienced male rats, using in vivo microdialysis, during copulation to satiety, when presented to a new sexually receptive female 24 h later, and during the pharmacological reversal of the sexual inhibition by anandamide.

RESULTS

NAcc DA levels remained increased during copulation to satiety. DA basal levels were significantly reduced 24 h after copulation to satiety, as compared to the initial basal levels. Presenting a receptive female behind a barrier 24 h after satiety did not induce the typical NAcc DA elevation in the sexually satiated males but there was a decrease that persisted when they got access to the female, with which they did not copulate. Anandamide injection slightly increased NAcc DA levels coinciding with sexual satiety reversal.

CONCLUSIONS

Reduced NAcc DA concentrations coincide with the inhibition of an instinctive, natural rewarding behavior suggesting that there might be a DA concentration threshold needed to be responsive to a rewarding stimulus.

Sexual Inhibition and Sexual Excitation Scales in Men: Psychometric Properties of a Polish Adaptation

The present study aimed to develop a Polish version of the Sexual Inhibition/Sexual Excitation Scale (SIS/SES-PL) and explore its psychometric validity in a sample of 498 men aged between 18 and 55 years. We used exploratory and confirmatory factor analyses to obtain the best model fit. Out of the 45 items in the original scale, 32 items with eight subscales and three higher-order factors: (sexual excitation [SES], sexual inhibition due to performance failure [SIS1], and sexual inhibition due to performance consequences [SIS2]) were included in the SIS/SES-PL. The SIS/SES-PL was found to have a good and satisfactory fit (comparative fit index = .87; Tucker-Lewis Index = .85; root mean square error of approximation = .054; χ² = 1108.7; p < .001; test-retest reliability Cronbach's alpha = .93). A small correlation between age and the SIS1 and SIS2 scores was detected. However, forward multiple regression analysis revealed a significant correlation only between age and SIS1 [β = .23, p < .001, R² for model = .05; F(1, 494) = 27.52, p < .001]. Furthermore, a moderate correlation between SIS1 and SES2, as well as SIS1 and general inhibition properties (measured using the Behavioral Inhibition Scale), was noted. In the case of SIS2, only small effects were observed, with the highest values for engaging in risky sexual behavior. Out of the total number of 42 variables, a moderate correlation between SES and the following was described: importance of sex, hypersexual behaviors, frequency of masturbation, frequency of sexual activities per month, sexual risk-taking, high promiscuity (measured using the Sociosexual Orientation Inventory Revised-Drive), general activation properties (measured using the Behavioral Activation Scale), neuroticism, and erotophilic tendencies (measured using the Sexual Opinion Survey-Short Form). The results of the study allowed us to conclude that the SIS/SES-PL might be a useful tool for tailoring therapy for men with sexual problems, as well as in the field of clinical research on sexual inhibition and excitation. Furthermore, it is a reliable and useful tool for measuring propensities for sexual excitement and inhibition.

Validation of the Sexual Inhibition/Sexual Excitation Scales (SIS/SES) in Italy: Assessing Gender and Age Differences of Sexual Functioning

The Sexual Inhibition Scales and Sexual Excitation Scales (Janssen et al., 2002a), based on the dual control model by Bancroft and Janssen (2000), are part of a 45-item self-report questionnaire evaluating individual tendencies to sexual inhibition or excitation according to three factors: two inhibition factors, SIS1, threat of performance failure, and SIS2, threat of performance consequences, and one excitation factor, SES. In this paper, we aimed to validate and explore psychometric properties of the SIS/SES in a sample of 2260 Italian men and women aged 18 to 75 years. Confirmatory factor analyses showed that the three-factor structure proposed in the original version of the scales fit with our sample. Moreover, our data confirmed the results of the original validation sample: Women scored higher on the SIS and lower on the SES than men did, but no significant differences appeared in the factor scores by age group, except for a gender × age interaction, where younger women had higher SIS2 scores. The SIS/SES appeared to be an effective, appropriate cross-cultural measurement of human sexuality in Italian samples, also shedding light on sexual arousal differences in women and men in our country. We also discuss clinical and therapeutic aspects.

Endocannabinoids mediate long-lasting behavioural and physiological changes in male rats induced by the repeated activation of the mesolimbic system by copulation to satiety

Sexually satiated male rats exhibit long-lasting physiological changes, suggestive of brain plasticity, the most conspicuous of which are a sexual behaviour inhibition and a generalised drug hypersensitivity. Copulation activates the mesolimbic circuit increasing dopamine (DA) release in the nucleus accumbens (NAcc) and, enhanced midbrain DA neuron activity promotes endocannabinoid (eCB) release in the ventral tegmental area (VTA). The objective of this work was to explore the possible participation of DA and/or eCB transmission in the induction of these two long-lasting phenomena. To this aim we analysed the effect of blocking DA or CB1 receptors during the process of copulation to exhaustion, on the expression 24 h later, of the sexual inhibitory state and the hypersensitivity to two different drugs: 8-OH-DPAT, a 5-HT_1A receptor agonist, and yohimbine, an α₂-adrenoceptor antagonist. Blockade of DA receptors failed to prevent these phenomena, while blockade of CB1 receptors interfered with the appearance of the sexual inhibition and the hypersensitivity to both drugs in the sexually satiated animals. Specific blockade of CB1 receptors in the VTA during copulation to satiety mimicked these results, suggesting that both eCB-mediated effects were exerted in this brain region. It is concluded that eCBs play a role in the induction of behavioural and physiological changes, triggered by copulation to satiety, by acting at the VTA, while increased NAcc DA levels appear not to contribute to the changes induced by intense copulation. Results pose sexual satiety as a useful model for the study of brain plasticity phenomena induced by natural rewards.

Dual Control Model in a Cross-Cultural Context: Role of Sexual Excitation in Sexual Response and Behavior Differences Between Chinese and Euro-Caucasian Women in Canada

Chinese women in Western nations frequently report less engagement with sexuality, such as lower sexual response and behaviors, and more restrictive sexual attitudes, than their Euro-Caucasian peers. This difference is likely related to sexual conservatism within traditional Chinese culture, though the mechanisms underlying how culture influences sexual responding are not well understood. The current study investigated if these differences were consistent with the dual control model, a well-established model for understanding regulation of sexual response. Chinese and Euro-Caucasian women (N = 471; age M = 20.7 years, SD = 3.3) residing in Canada from a university sample completed self-report questionnaires on sexual excitation and inhibition, sexual attitudes, and various sexual response and behavior measures. Sexual excitation was significantly lower in Chinese than Euro-Caucasian women and was significantly associated with sexual response in both groups. Structural equation modeling showed that sexual response variables were associated with a latent sexual excitation factor and that sexual attitudes partially mediated the relationship between this latent factor and ethnicity. The findings showed that sexual excitation and sexual attitudes contribute to cross-cultural differences in women's sexual responding. Theoretical and clinical considerations are discussed.

A Validation Study of the German Version of the Sexual Inhibition/Sexual Excitation Scales-Short Form

The dual control model of human sexual behavior proposes that sexual responses involve an interaction between sexual excitatory and sexual inhibitory systems. The Sexual Inhibition/Sexual Excitation Scales (SIS/SES; Janssen, Vorst, Finn, & Bancroft, 2002) as well as its short form (SIS/SES-SF; Carpenter, Janssen, Graham, Vorst, & Wicherts, 2011) assess individual propensities to become sexually excited and sexually inhibited. The present study utilized a dataset of 2221 German-speaking adults (n = 1214 women and n = 987 men) to examine the psychometric properties of the German version of the SIS/SES-SF. The results of the confirmatory factor analysis indicated that the three factors suggested in the original version can be generally replicated within the current study. Analyses of measurement invariance for gender revealed that the general three-factor structure as well as factor loadings can be regarded as equal for men and women. However, scalar invariance could not be fully obtained, indicating that the intercepts of some items were different for men and women. Taken together, the results of the presents study provide further evidence for the psychometric properties of the German version of the SIS/SES-SF.

Temporal Stability of Sexual Excitation and Sexual Inhibition in Women

The dual control model of sexual response proposes two factors, sexual excitation (SE) and sexual inhibition (SI), that aim to predict sexual behavior and response. While SE and SI are described as stable traits that influence sexuality-related outcomes such as sexual function or sexual risk taking, only a few studies have presented data on the stability of these factors. The aim of this study was to evaluate the temporal stability of SE and SI, and to investigate whether changes in sexual function or partnership status influence SE and SI in a longitudinal sample of women. To address these research questions, the Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W) was administered five times over the course of 4 years. The SESII-W includes two main scales of SE and SI which consist of five (Arousability, Partner characteristics, Sexual power dynamics, Smell, and Setting) and three subscales (Concerns about sexual function, Arousal contingency, Relationship importance), respectively. Data from 553 women (M_age = 31.38 years, SD = 10.25, range = 18-67) who participated in at least two assessment points were included in this study. Bivariate correlations between baseline and the fifth follow-up assessment indicated a high temporal stability of SE and SI in women (.47 < r < .71). A series of generalized linear models were conducted to investigate the impact of time, changes in sexual function, partnership status, and changes in partnership status on SE and SI. Partner characteristics (SE) that showed small increases over time. Across different subscales, improvements in sexual function were associated with higher SE and lower SI. Changes in partnership status and partnership status itself were predictors of one SE- and three SI-related scales. This study suggests a relatively high temporal stability of SE and SI in women and supports the dual control model's assertion that both factors are stable individual traits. Certain life events such as a new partnership or sexual difficulties may, however, impact time stability of both factors.

Approach and Avoidance Biases Toward Sexual Stimuli and Their Association with the Dual Control Model of Sexual Response in Heterosexual Men

Many models of human behavior work in an interaction of a dual system. While one system usually represents controlled and reflective behavioral responses, the other system reflects automatic and impulsive actions. In the impulsive system, positive stimuli initiate approach reactions and negative cues avoidance reactions. Besides stimulus valence, the behavioral response triggered by the impulsive system is influenced by personality (e.g., the propensity to react with approach or avoidance biases in a specific situation). The present study applied a computerized Approach-Avoidance Task (AAT; Rinck & Becker, 2007) to assess automatic behavioral approach and avoidance biases toward sexual and neutral stimuli in heterosexual men (N = 40). Individual AAT-performance was furthermore related to sexual excitation (SES) and the two sexual inhibition factors (SIS1 and SIS2) as proposed by the Dual Control Model of sexual response (Bancroft & Janssen, 2000). Against our hypotheses, participants did not show a stronger approach bias toward sexually preferred (i.e., images of women) than sexually not preferred stimuli (i.e., images of men or children). However, stronger approach biases toward images of women were positively associated with sexual excitation and negatively correlated with sexual inhibition due to a threat of performance failure (SIS1) even after controlling for potential confounds (i.e., general behavioral activation and inhibition). The results support the importance of the influence of dispositional traits measured with the Dual Control Model of sexual response on approach and avoidance biases toward sexually preferred stimuli in heterosexual men.

The Role of Inhibitory Control Mechanisms in the Regulation of Sexual Behavior

Sexual behavior is the open manifestation of a complex interplay between psychophysiological mechanisms that either facilitate or inhibit sexual thoughts, desires, and associated behaviors. Whereas sexual excitation has been widely studied, less is known about the impact of inhibitory control mechanisms that enable individuals to refrain from sexual cognition and behavior. The present study examined: (1) the relationship between general and sexual inhibitory mechanisms (as measured through self-reports and computer-based tasks), (2) the relation between sexual inhibitory processes at cognitive and motor-motivational levels and with sexual inhibition as an individual trait, and (3) the predictive value of these parameters on sexual thoughts (cognition) and behavior. We demonstrate that general inhibitory control (i.e., the ability to suppress any preponderant response) and the specific inhibition of sexual responses represent distinct processes that require at least partly different control mechanisms. Similarly, the ability to inhibit sexual visual input and the ability to suppress sexually driven responses seem to be two independent processes. The different inhibitory processes distinctively predicted the frequency of sexual thoughts and sexual behavior. We propose that these different inhibitory mechanisms are at play during different phases of sexual regulation (before and after the generation and unfolding of sexual arousal) and that a specific deficit in one of these processes may underlie the distinctive symptomatology and comorbidity of sexual disorders.

Psychometric Properties of the Spanish Version of the Sexual Inhibition/Sexual Excitation Scales for Men

The dual control model (DCM) postulates the involvement of relatively independent inhibitory and excitatory systems, which together provide a "double control" over sexual response and associated behavior (Janssen & Bancroft, 2007). Based on this model, the Sexual Inhibition and Sexual Excitation Scales assess the propensity for sexual excitation and sexual inhibition. This research focused on analyzing some psychometric properties of this questionnaire and developing a Spanish version in men. The sample consisted of 823 heterosexual men of ages ranging from 18 to 74 years. Confirmatory factor analysis generated a version of the scale that consisted of 34 items (11 items with the worst factor loadings were eliminated) distributed in four factors (one sexual excitation factor and three sexual inhibition factors). This is consistent with the DCM of sexual response. The four factors demonstrated good reliability coefficients except for sexual inhibition due to the threat of performance consequences, which was found to have a low internal consistency. Consequently, this is something that will be addressed in future studies. The four factors were found to have good test-retest reliability. The measures of the Sexual Inhibition and Sexual Excitation Scales had good validity properties and a coherent relationship with sexual sensation seeking and erotophilia.

An Online Assessment of Personality, Psychological, and Sexuality Trait Variables Associated with Self-Reported Hypersexual Behavior

"Hypersexual" behavior represents a perceived inability to control one's sexual behavior. To investigate hypersexual behavior, an international sample of 510 self-identified heterosexual, bisexual, and homosexual men and women completed an anonymous online self-report questionnaire battery. In addition to age and sex (male), hypersexual behavior was related to higher scores on measures of sexual excitation, sexual inhibition due to the threat of performance failure, trait impulsivity, and both depressed mood and anxiety. In contrast, hypersexual behavior was related to lower scores on sexual inhibition due to the threat of performance consequences. Higher neuroticism and extraversion, as well as lower agreeableness and conscientiousness, also predicted hypersexual behavior. Interestingly, interactions among the variables assessed did not significantly predict hypersexual behavior, suggesting the possible existence of multiple and predominantly independent taxa for various persons reporting hypersexual behavior. Core personality features may also be present in persons with hypersexual behavior. Clinical implications and future research directions are discussed.

A new role for GABAergic transmission in the control of male rat sexual behavior expression

GABAergic transmission in the ventral tegmental area (VTA) exerts a tonic inhibitory influence on mesolimbic dopaminergic neurons' activity. Blockade of VTA GABA_A receptors increases dopamine release in the nucleus accumbens (NAcc). Increases in NAcc dopamine levels typically accompany sexual behavior display. Copulation to satiety is characterized by the instatement of a long lasting (72h) sexual behavior inhibition and the mesolimbic system appears to be involved in this phenomenon. GABAergic transmission in the VTA might play a role in the maintenance of this long lasting sexual inhibitory state. To test this hypothesis, in the present work we investigated the effect of GABA_A receptor blockade in sexually exhausted males 24h after copulation to satiety, once the sexual inhibitory state is established, and compared it with its effect in sexually experienced rats. Results showed that low doses of systemically administered bicuculline induced sexual behavior expression in sexually exhausted rats, but lacked an effect on copulation of sexually experienced animals. Intra-VTA bilateral infusion of bicuculline did not modify sexual behavior of sexually experienced rats, but induced sexual behavior expression in all the sexually exhausted males. Hence, GABA plays a role in the control of sexual behavior expression at the VTA. The role played by GABAergic transmission in male sexual behavior expression of animals with distinct sexual behavior conditions is discussed.

Investigating Female Sexual Concordance: Do Sexual Excitation and Sexual Inhibition Moderate the Agreement of Genital and Subjective Sexual Arousal in Women?

The agreement of subjective and genital sexual response, also referred to as sexual concordance, shows substantial variability between women. Identifying predictors of sexual arousal and sexual concordance is important to improve our understanding of female sexual response and its relationship to sexual function or dysfunction. The aim of this study was to assess the relevance of sexual excitation and sexual inhibition as predictors of subjective sexual arousal, genital arousal, and sexual concordance. In a laboratory setting, sexual arousal was induced by erotic video stimuli. Subjective sexual arousal was assessed continuously during stimulus presentation and genital arousal was measured with vaginal photoplethysmography. Data of 58 women (M age = 24.95, SD = 4.65) were analyzed using multilevel analyses (HLM). This data analytic technique estimates the within-subject associations of subjective and genital arousal, by controlling for between-subject differences. An interaction term of sexual excitation and sexual inhibition significantly predicted genital sexual arousal. In exploratory analyses, two lower order factors of sexual inhibition (Concerns about Sexual Function and Arousal Contingency) were predictive of sexual concordance. Further examination of these associations might increase our knowledge of female sexual function and deepen our understanding of how sexual excitation and sexual inhibition affect sexual arousal and consequently, impact sexual behaviors, in women.

Content and Valence of Sexual Cognitions and Their Relationship With Sexual Functioning in Spanish Men and Women

This study examined the relationship between various subtypes of positive and negative sexual cognitions (NSC) based on their content (intimate, exploratory, sadomasochistic, impersonal) and sexual functioning, including aspects of sexual response (desire), sexual motivation (sexual excitation and sexual inhibition), and cognitive-affective domains (satisfaction). Participants were 789 Spanish adults (322 men and 467 women) who were in a heterosexual relationship of at least 6 months duration. Overall, the men reported more frequent exploratory and impersonal positive sexual cognitions than did the women. The men and women did not differ in the frequency of their positive intimate and sadomasochistic cognitions or in any of their NSC. Using canonical correlation, the results revealed that, after controlling for the overall frequency of NSC, the men and women who reported a higher frequency of all subtypes of positive sexual cognitions reported more dyadic and solitary sexual desire, more propensity to get sexually excited, and less sexual inhibition. A second canonical variate was identified for both the men and the women that revealed different patterns of association between the subtypes of cognitions and specific areas of sexual functioning, highlighting the role of positive, intimate cognitions for dyadic aspects of sexual functioning. The subtypes of NSC were not associated with poorer sexual functioning for either men or women, perhaps because they, on average, occurred infrequently. The findings were discussed in terms of the relationship between the specific content of sexual cognitions and the sexual functioning of men and women.

Psychometric Properties of the Sexual Excitation/Sexual Inhibition Inventory for Women in a German Sample

The Sexual Excitation Sexual/Inhibition Inventory for Women (SESII-W) is a self-report questionnaire for assessing propensities of sexual excitation (SE) and sexual inhibition (SI) in women. According to the dual control model of sexual response, these two factors differ between individuals and influence the occurrence of sexual arousal in given situations. Extreme levels of SE and SI are postulated to be associated with sexual problems or risky sexual behaviors. Psychometric evaluation of the original scale yielded two higher order and eight lower order factors as well as satisfactory to good construct validity and reliability. The present study was designed to assess the psychometric properties of a German version of the SESII-W utilizing a large convenience sample of 2206 women. Confirmatory factor analysis showed a satisfactory overall model fit, with support for the five lower order factors of SE (Arousability, Sexual Power Dynamics, Smell, Partner Characteristics, Setting) and the three lower order factors of SI (Relationship Importance, Arousal Contingency, and Concerns about Sexual Function). Additionally, the scale demonstrated good convergent and discriminant validity, internal consistency, and test-retest-reliability. The German SESII-W is a sufficiently reliable and valid measure for assessing SE and SI in women. Hence, its use can be recommended for future research in Germany that investigates women's sexual behaviors and experiences.