Altered States and Social Bonds: Effects of MDMA and Serotonergic Psychedelics on Social Behavior as a Mechanism Underlying Substance-Assisted Therapy

There has been renewed interest in the use of 3,4-methylenedioxy-methamphetamine (MDMA) and serotonergic psychedelics in the treatment of multiple psychiatric disorders. Many of these compounds are known to produce prosocial effects, but how these effects relate to therapeutic efficacy and the extent to which prosocial effects are unique to a particular drug class is unknown. In this article, we present a narrative overview and compare evidence for the prosocial effects of MDMA and serotonergic psychedelics to elucidate shared mechanisms that may underlie the therapeutic process. We discuss 4 categories of prosocial effects: altered self-image, responses to social reward, responses to negative social input, and social neuroplasticity. While both categories of drugs alter self-perception, MDMA may do so in a way that is less related to the experience of mystical-type states than serotonergic psychedelics. In the case of social reward, evidence supports the ability of MDMA to enhance responses and suggests that serotonergic psychedelics may also do so, but more research is needed in this area. Both drug classes consistently dampen reactivity to negative social stimuli. Finally, preclinical evidence supports the ability of both drug classes to induce social neuroplasticity, promoting adaptive rewiring of neural circuits, which may be helpful in trauma processing. While both MDMA and serotonergic psychedelics produce prosocial effects, they differ in the mechanisms through which they do this. These differences affect the types of psychosocial interventions that may work best with each compound.

Inhibitory dysfunction and social processing difficulties in autism: A comprehensive narrative review

The primary inhibitory neurotransmitter γ-aminobutyric acid (GABA) has a prominent role in regulating neural development and function, with disruption to GABAergic signalling linked to behavioural phenotypes associated with neurodevelopmental disorders, particularly autism. Such neurochemical disruption, likely resulting from diverse genetic and molecular mechanisms, particularly during early development, can subsequently affect the cellular balance of excitation and inhibition in neuronal circuits, which may account for the social processing difficulties observed in autism and related conditions. This comprehensive narrative review integrates diverse streams of research from several disciplines, including molecular neurobiology, genetics, epigenetics, and systems neuroscience. In so doing it aims to elucidate the relevance of inhibitory dysfunction to autism, with specific focus on social processing difficulties that represent a core feature of this disorder. Many of the social processing difficulties experienced in autism have been linked to higher levels of the excitatory neurotransmitter glutamate and/or lower levels of inhibitory GABA. While current therapeutic options for social difficulties in autism are largely limited to behavioural interventions, this review highlights the psychopharmacological studies that explore the utility of GABA modulation in alleviating such difficulties.

Epigenetic modification of the oxytocin receptor gene is associated with child-parent neural synchrony during competition

Interpersonal neural synchrony (INS) occurs when neural electrical activity temporally aligns between individuals during social interactions. It has been used as a metric for interpersonal closeness, often during naturalistic child-parent interactions. This study evaluated whether other biological correlates of social processing predicted the prevalence of INS during child-parent interactions, and whether their observed cooperativity modulated this association. Child-parent dyads (n = 27) performed a visuospatial tower-building task in cooperative and competitive conditions. Neural activity was recorded using mobile electroencephalogram (EEG) headsets, and experimenters coded video-recordings post-hoc for behavioral attunement. DNA methylation of the oxytocin receptor gene (OXTRm) was measured, an epigenetic modification associated with reduced oxytocin activity and socioemotional functioning. Greater INS during competition was associated with lower child OXTRm, while greater behavioral attunement during competition and cooperation was associated with higher parent OXTRm. These differential relationships suggest that interpersonal dynamics as measured by INS may be similarly reflected by other biological markers of social functioning, irrespective of observed behavior. Children's self-perceived communication skill also showed opposite associations with parent and child OXTRm, suggesting complex relationships between children's and their parents' social functioning. Our findings have implications for ongoing developmental research, supporting the utility of biological metrics in characterizing interpersonal relationships.

Objects in a social world: Infants' object representational capacity limits are shaped by objects' social relevance

Several decades of research have revealed consistent signature limits on infants' ability to represent objects. However, these signature representational limits were established with methods that often removed objects from their most common context. In infants' everyday lives, objects are very often social artifacts: they are the targets of agents' goal-directed actions, communications, and beliefs, and may have social content or relevance themselves. In this chapter, we explore the relationship between infants' object representational capacity limits and their processing of the social world. We review evidence that the social content and context of objects can shift infants' object representational limits. We discuss how taking the social world into account can yield more robust and ecologically valid estimates of infants' early representational capacities.

Associations between age, social reward processing and social anxiety symptoms

Reward processing undergoes marked changes in adolescence, with social interactions representing a powerful source of reward. Reward processing is also an important factor in the development of social anxiety disorder, a condition that most commonly first appears in adolescence. This study investigated the relationship between age, social reward processing and social anxiety in a cross-sectional sample of female participants (N = 80) aged 13-34. Participants performed two versions of a probabilistic reward anticipation task, in which a speeded response could result in different probabilities of receiving either social or monetary rewarding feedback. Participants also completed self-report assessments of social reward value, trait anxiety and social anxiety symptoms. At high reward probabilities, performance on both reward tasks showed a quadratic effect of age, with the fastest responses at around 22-24 years. A similar quadratic effect was found for subjective liking ratings of both reward stimuli, although these were not associated with performance. Social anxiety was not associated with a subjective liking of the rewards but did predict performance on both tasks at all reward probabilities. Age-related variation in reward processing was not accounted for by age-related variation in social anxiety symptoms, suggesting that, while both social anxiety and age were associated with variation in reward processing, their effects were largely independent. Together, these findings provide evidence that social reward processing continues to develop across adolescence and that individual differences in social anxiety should be considered when considering reward sensitivity during this period.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12144-023-04551-y.

Borderline personality features and altered social feedback processing in emerging adults: An EEG study

The goal of this study was to examine social feedback processing among emerging adults with borderline personality features (BPF). Participants (N = 118; 66.9% female) completed ratings of BPF and a computerized peer interaction task designed to measure processing of rejection and acceptance cues at the neurophysiological (i.e., electroencephalogram [EEG]), behavioral, and self-report levels. When covarying symptoms of depression and social anxiety, greater BPF were associated with heightened neural processing of social acceptance cues, accounting for reactivity to neutral and rejection cues, as demonstrated by an enhanced reward positivity (RewP) component. Additionally, BPF were associated with less adaptive voting in response to peer acceptance, such that emerging adults with higher BPF made fewer votes to keep peers in the game who had provided acceptance feedback to participants. These neural and behavioral patterns associated with BPF highlight the potential role of social reward processing in borderline personality. Specifically, emerging adults high in BPF show a hyper-responsiveness to social acceptance at the neural level but difficulty modulating behavioral responses in an adaptive way to obtain more social rewards. Future research replicating these effects across development may guide efforts to address and prevent the profound social dysfunction associated with BPF.

Social visual attentional engagement and memory in Phelan-McDermid syndrome and autism spectrum disorder: a pilot eye tracking study

BACKGROUND

The current study used eye tracking to investigate attention and recognition memory in Phelan-McDermid syndrome (PMS), a rare genetic disorder characterized by intellectual disability, motor delays, and a high likelihood of comorbid autism spectrum disorder (ASD). Social deficits represent a core feature of ASD, including decreased propensity to orient to or show preference for social stimuli.

METHODS

We used a visual paired-comparison task with both social and non-social images, assessing looking behavior to a novel image versus a previously viewed familiar image to characterize social attention and recognition memory in PMS (n = 22), idiopathic ASD (iASD, n = 38), and typically developing (TD) controls (n = 26). The idiopathic ASD cohort was divided into subgroups with intellectual disabilities (ID; developmental quotient < 70) and without (developmental quotient > 70) and the PMS group into those with and without a co-morbid ASD diagnosis.

RESULTS

On measures of attention, the PMS group with a comorbid ASD diagnosis spent less time viewing the social images compared to non-social images; the rate of looking back and forth between images was lowest in the iASD with ID group. Furthermore, while all groups demonstrated intact recognition memory when novel non-social stimuli were initially presented (pre-switch), participants with PMS showed no preference during the post-switch memory presentation. In iASD, the group without ID, but not the group with ID, showed a novelty preference for social stimuli. Across indices, individuals with PMS and ASD performed more similarly to PMS without ASD and less similarly to the iASD group.

CONCLUSION

These findings demonstrate further evidence of differences in attention and memory for social stimuli in ASD and provide contrasts between iASD and PMS.

A systematic review and meta-analysis of 'Systems for Social Processes' in borderline personality and substance use disorders

Deficits in social processing (SP) have been proposed to underpin interpersonal dysfunction in both Borderline Personality Disorder (BPD) and Substance Use Disorders (SUD). This study aimed to explore potential transdiagnostic cognitive and behavioral phenotypes of these disorders utilizing the NIMH Research Domain Criteria 'Systems for Social Processes'. A systematic review and meta-analysis of the published research was conducted on 134 studies identified through our database searches. Four meta-analyses were conducted, which revealed significant overlapping deficits in the ability to identify facial emotions and infer the mental states of others in both BPD and SUD. Further, people with BPD displayed a higher ostracism effect following perceived social exclusion. Systematically reviewed studies also revealed significant dysfunction amongst individuals with BPD and SUD across both self and other SP constructs, which were broadly similar in magnitude. Taken together, these results support the proposition that SP dysfunction may be considered a core transdiagnostic phenotype of BPD and SUD.

Enhanced detection of gaze toward an object: Sociocognitive influences on visual search

Another person's gaze direction is a rich source of social information, especially eyes gazing toward prominent or relevant objects. To guide attention to these important stimuli, visual search mechanisms may incorporate sophisticated coding of eye-gaze and its spatial relationship to other objects. Alternatively, any guidance might reflect the action of simple perceptual 'templates' tuned to visual features of socially relevant objects, or intrinsic salience of direct-gazing eyes for human vision. Previous findings that direct gaze (toward oneself) is prioritised over averted gaze do not distinguish between these accounts. To resolve this issue, we compared search for eyes gazing toward a prominent object versus gazing away, finding more efficient search for eyes 'gazing toward' the object. This effect was most clearly seen in target-present trials when gaze was task-relevant. Visual search mechanisms appear to specify gazer-object relations, a computational building-block of theory of mind.

Memory updating through aging: different patterns for socially meaningful (and not) stimuli

BACKGROUND

Updating is a crucial function responsible of working memory integrity, allowing relevant information to be active and inhibiting irrelevant one; updating has been studied mainly with verbal stimuli, less with faces, stimuli with high adaptive value and social meaning.

AIM

Our aim was to test age-related differences in updating for different stimuli in three different age groups: young adults (range 20-30 years), young-old (range 60-75 years) and older-old participants (range 77-87 years).

METHODS

To this end, we administered control measures (i.e., vocabulary and visuospatial tasks), span tasks (forward, backward) and two updating tasks: one with no socially relevant material (i.e., letters) and another one with socially relevant material (i.e., human faces, where, in particular, the combination between facial expression and gaze direction was manipulated). In both tasks we collected response times (RTs) at different steps of an updating task (i.e., encoding, maintaining, and updating goal-relevant information).

RESULTS AND DISCUSSION

We found that age linearly produces an increase in processing speed regardless the stimulus considered, either letter or human face. However, with face stimuli, the magnitude of the difference is greater for the letter updating task, than for the face updating task. In turn, the results claim for a stimulus-specific updating process as the age-related decline is less pronounced when socially meaningful stimuli are involved than when no socially meaningful ones are.

Social processing by the primate medial frontal cortex

The primate medial frontal cortex is comprised of several brain regions that are consistently implicated in regulating complex social behaviors. The medial frontal cortex is also critically involved in many non-social behaviors, such as those involved in reward, affective, and decision-making processes, broadly implicating the fundamental role of the medial frontal cortex in internally guided cognition. An essential question therefore is what unique contributions, if any, does the medial frontal cortex make to social behaviors? In this chapter, we outline several neural algorithms necessary for mediating adaptive social interactions and discuss selected evidence from behavioral neurophysiology experiments supporting the role of the medial frontal cortex in implementing these algorithms. By doing so, we primarily focus on research in nonhuman primates and examine several key attributes of the medial frontal cortex. Specifically, we review neuronal substrates in the medial frontal cortex uniquely suitable for enabling social monitoring, observational and vicarious learning, as well as predicting the behaviors of social partners. Moreover, by utilizing the three levels of organization in information processing systems proposed by Marr (1982) and recently adapted by Lockwood, Apps, and Chang (2020) for social information processing, we survey selected social functions of the medial frontal cortex through the lens of socially relevant algorithms and implementations. Overall, this chapter provides a broad overview of the behavioral neurophysiology literature endorsing the importance of socially relevant neural algorithms implemented by the primate medial frontal cortex for regulating social interactions.

Development of the Stanford Social Dimensions Scale: initial validation in autism spectrum disorder and in neurotypicals

Background

The aim of this paper was to provide an initial validation of a newly developed parent questionnaire-the Stanford Social Dimensions Scale (SSDS), designed to capture individual differences across several key social dimensions including social motivation in children and adolescents with and without psychiatric disorders.

Methods

The initial validation sample was comprised of parents of 175 individuals with autism spectrum disorder (ASD) (35 females, 140 males; Mage = 7.19 years, SDage = 3.96) and the replication sample consisted of 624 parents of children who were either typically developing or presented with a range of neurodevelopmental and neuropsychiatric disorders (302 females, 322 males; Mage = 11.49 years, SDage = 4.48). Parents from both samples completed the SSDS and the Social Responsiveness Scale (SRS-2).

Results

Exploratory Structural Equation Modeling indicated that a 5-factor model provided adequate to excellent fit to the data in the initial ASD sample (comparative fit index [CFI] = .940, Tucker-Lewis Index [TLI] = .919, root mean square error of approximation [RMSEA] = .048, standardized root mean square residual [SRMR] = .038). The identified factors were interpreted as Social Motivation, Social Affiliation, Expressive Social Communication, Social Recognition, and Unusual Approach. This factor structure was further confirmed in Sample 2 (CFI = 946, TLI = .930, RMSEA = .044, SRMR = .026). Internal consistency for all subscales was in the good to excellent range across both samples as indicated by Composite Reliability scores of ≥ .72. Convergent and divergent validity was strong as indexed by the pattern of correlations with relevant SRS-2 and Child Behavior Checklist domains and with verbal and non-verbal intellectual functioning scores in Sample 1 and with the Need to Belong Scale and Child Social Preference Scale scores in Sample 2. Across both samples, females had higher social motivation and expressive social communication scores. Discriminant validity was strong given that across all SSDS subscales, the ASD sample had significantly higher impairment than both the typically developing group and the group with other clinical conditions, which in turn, had significantly higher impairment than the typically developing group.

Conclusions

Our findings provide initial validation of a new scale designed to comprehensively capture individual differences in social motivation and other key social dimensions in ASD.

Automatic visual-spatial perspective taking in alcohol-dependence: A study with happy emotional faces

BACKGROUND

Understanding the world from another's perspective is an important and potentially automatic human process which is crucial for efficient social interactions. However, while deficits have repeatedly been described for various interpersonal abilities in alcohol-dependence (AD), only one previous study has investigated perspective taking in this pathology.

AIM

The current study aimed to explore further how AD affects visual-spatial perspective taking (VSPT) by examining the effect of positive emotional stimuli on VSPT in both an AD and non-AD sample.

METHODS

Reaction times (RT) for simple spatial judgments were measured. Participants made these judgments from their perspective, but judgments were either congruent or incongruent with the perspective of another agent. The emotion conveyed by that agent (happy or neutral) was manipulated across trials.

RESULTS

Compared to baseline, both AD and non-AD groups displayed delayed RTs for spatial judgments when these were incongruent with the perspective of a happy agent (the expected VSPT RT cost, indicating automatic VSPT). The AD, but not the non-AD group, further displayed a VSPT RT cost when the agent expressed a neutral emotion.

CONCLUSION

There was no evidence that AD compromised automatic VSPT. However, as in previous research, AD was associated with differences in the processing of emotional stimuli. Future research should explore which 'real-world' settings are likely to trigger social confusion and misunderstanding.

Aspects of alcohol use disorder affecting social cognition as assessed using the Mini Social and Emotional Assessment (mini-SEA)

BACKGROUND

Alcohol Use Disorder (AUD) is associated with problems with processing complex social scenarios. Little is known about the relationship between distinct AUD-related factors (e.g., years of problematic drinking), aspects of cognitive function and dysfunction in individuals diagnosed with AUD, and the relative impact these may have on social cognition.

AIMS

To explore differences in social cognition between a group of participants diagnosed with AUD and controls, using a clinical measure, the Mini Social and Emotional Assessment (mini-SEA). The mini-SEA was used to evaluate social and emotional understanding through a facial emotional recognition task and by utilising a series of social scenes some of which contain a faux pas (social error).

METHODS

Eighty-five participants (individuals with AUD and controls) completed demographic questions and a general cognitive and social cognitive test battery over three consecutive days.

RESULTS

Between group analyses revealed that the participants with AUD performed less well on the faux pas test, and differences were also revealed in the emotional facial recognition task. Years of problematic alcohol consumption was the strongest predictor of poor ToM reasoning.

CONCLUSION

These results suggest a strong link between AUD chronicity and social cognition, though the direction of this relationship needs further elucidation. This may be of clinical relevance to abstinence and relapse management, as basic social cognition skills and ability to maintain interpersonal relationships are likely to be crucial to recovery.

Objective measurement of head movement differences in children with and without autism spectrum disorder

Background

Deficits in motor movement in children with autism spectrum disorder (ASD) have typically been characterized qualitatively by human observers. Although clinicians have noted the importance of atypical head positioning (e.g. social peering and repetitive head banging) when diagnosing children with ASD, a quantitative understanding of head movement in ASD is lacking. Here, we conduct a quantitative comparison of head movement dynamics in children with and without ASD using automated, person-independent computer-vision based head tracking (Zface). Because children with ASD often exhibit preferential attention to nonsocial versus social stimuli, we investigated whether children with and without ASD differed in their head movement dynamics depending on stimulus sociality.

Methods

The current study examined differences in head movement dynamics in children with (n = 21) and without ASD (n = 21). Children were video-recorded while watching a 16-min video of social and nonsocial stimuli. Three dimensions of rigid head movement—pitch (head nods), yaw (head turns), and roll (lateral head inclinations)—were tracked using Zface. The root mean square of pitch, yaw, and roll was calculated to index the magnitude of head angular displacement (quantity of head movement) and angular velocity (speed).

Results

Compared with children without ASD, children with ASD exhibited greater yaw displacement, indicating greater head turning, and greater velocity of yaw and roll, indicating faster head turning and inclination. Follow-up analyses indicated that differences in head movement dynamics were specific to the social rather than the nonsocial stimulus condition.

Conclusions

Head movement dynamics (displacement and velocity) were greater in children with ASD than in children without ASD, providing a quantitative foundation for previous clinical reports. Head movement differences were evident in lateral (yaw and roll) but not vertical (pitch) movement and were specific to a social rather than nonsocial condition. When presented with social stimuli, children with ASD had higher levels of head movement and moved their heads more quickly than children without ASD. Children with ASD may use head movement to modulate their perception of social scenes.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0198-4) contains supplementary material, which is available to authorized users.

The OXTR gene, implicit learning and social processing: Does empathy evolve from perceptual skills for details?

Oxytocin is an important messenger in the brain that has been linked to a variety of social functions in pharmacological studies. Besides, functional genetic variations on the oxytocin receptor gene have been repeatedly associated with social processing and functioning. Despite this knowledge, there are very few studies investigating the mechanisms that may explain the link between oxytocin and social functions. In the endeavor to fill this gap in the literature, the current study searches for associations between the prominent rs2268498 polymorphism on the oxytocin receptor gene and participants' ability to perceive and store implicit social information, which is a fundamental function in social information processing. N=121 healthy participants were experimentally tested with an implicit learning paradigm, answered questionnaires assessing empathy and autistic traits, and were genotyped for the rs2268498 polymorphism. T-allele carriers (TT and TC genotypes) exhibited significantly better implicit learning performance than carriers of the CC-genotype, and learning performance was positively associated with self-reported empathy and negatively with self-reported autistic traits. Results indicate that differences in implicit perception and storing of environmental details while watching social interactions could be an important mechanism to explain the association between differences in endogenous oxytocin activity and social functioning.

The effect of alcohol dependence on automatic visuo-spatial perspective taking

BACKGROUND

Alcoholism is associated with cognitive deficits that affect social functioning. Previous research has shown that alcoholism is associated with deficits in conscious, deliberate social processing. However, little is known about whether alcoholism also affects rapid, spontaneous processing. We therefore investigated the extent to which alcoholism affects the ability to spontaneously adopt the viewpoint of another in a visuo-spatial perspective taking (VSPT) task.

METHODS

VSPT was measured in participants responding to a dot probe presented for 35ms alongside neutral faces, fearful faces and baseline stimuli (rectangles).

RESULTS

Non alcohol dependent participants showed the standard reaction time cost to fearful faces, but not neutral faces relative to baseline. However, Alcohol dependent (AD) participants showed a reaction time cost to both fearful and neutral faces.

CONCLUSIONS

AD participants are not impaired in their ability to automatically adopt the perspective of another. However, unlike non-AD participants, they show automatic perspective taking to both neutral and fearful faces.

You may now kiss the bride: Interpretation of social situations by individuals with right or left hemisphere injury

While left hemisphere damage (LHD) has been clearly shown to cause a range of language impairments, patients with right hemisphere damage (RHD) also exhibit communication deficits, such as difficulties processing prosody, discourse, and social contexts. In the current study, individuals with RHD and LHD were directly compared on their ability to interpret what a character in a cartoon might be saying or thinking, in order to better understand the relative role of the right and left hemisphere in social communication. The cartoon stimuli were manipulated so as to elicit more or less formulaic responses (e.g., a scene of a couple being married by a priest vs. a scene of two people talking, respectively). Participants' responses were scored by blind raters on how appropriately they captured the gist of the social situation, as well as how formulaic and typical their responses were. Results showed that RHD individuals' responses were rated as significantly less appropriate than controls and were also significantly less typical than controls and individuals with LHD. Individuals with RHD produced a numerically lower proportion of formulaic expressions than controls, but this difference was only a trend. Counter to prediction, the pattern of performance across participant groups was not affected by how constrained/formulaic the social situation was. The current findings expand our understanding of the roles that the right and left hemispheres play in social processing and communication and have implications for the potential treatment of social communication deficits in individuals with RHD.