International Journal of Neuropsychopharmacology

Social withdrawal is a key component of the negative symptom domain of schizophrenia, and pharmacological blockade of the N-methyl-D-aspartate receptor (NMDAR) is widely used to model schizophrenia-relevant phenotypes in animals. However, findings on social behaviour are inconsistent across paradigms and laboratories. We therefore conducted a systematic review and meta-analysis to synthesise the effects of dizocilpine, ketamine, and phencyclidine on social interaction and social preference, to evaluate whether clinically approved antipsychotics modify these outcomes, and to examine locomotor activity measured within the same social tests to aid interpretation. We searched Embase, PubMed and Web of Science without language or date restrictions. Controlled in vivo studies in laboratory animals administering an eligible NMDAR antagonist and reporting social interaction and/or social preference outcomes were included. Two reviewers independently screened records, extracted data and assessed risk of bias. Effect sizes were computed as standardised mean differences and synthesised using correlated multilevel random-effects models with cluster-robust variance estimation. In total, 264 studies met the inclusion criteria. Overall, NMDAR antagonists were associated with reduced social interaction and reduced social preference relative to controls, although the social preference literature appeared vulnerable to small-study effects and imprecision. Locomotor activity measured during social interaction tests tended to be higher following NMDAR antagonists, whereas during social preference no consistent overall change was observed. In animals exposed to NMDAR antagonists, antipsychotics increased social behaviour, but these changes commonly co-occurred with reduced locomotion during social interaction tests, suggesting that improvements in social measures may partly reflect altered behavioural competition and time allocation rather than selective restoration of social functioning. Taken together, the evidence supports an overall link between NMDAR antagonism and reduced social behaviour, but the strength and interpretability of this signal depend on the paradigm and are constrained by heterogeneity and limitations in reporting.

Background and PurposeWhile inflammation has been generally considered to exacerbate symptoms of schizophrenia, some clinical observations suggest that acute inflammation may alleviate positive symptoms. However, animal models often use excessive inflammatory stimuli, and the effects of acute inflammation--comparable to levels observed in patients--remain unknown. Experimental ApproachTo address this, we examined whether acute inflammation induced under relatively mild, clinically relevant conditions suppresses behavioural sensitization in methamphetamine (METH)-sensitized mice, a model of psychostimulant-induced psychosis with relevance to certain aspects of positive symptoms of schizophrenia. We used a repeated METH (1 mg/kg) sensitized model to evaluate the effects of acute inflammation on behavioural sensitization. Acute inflammation was induced via two methods using either lipopolysaccharides (LPS; 1 g/kg) to mimic peripheral immune activation or restraint stress (RS; single 2-h exposure) to model the neuroinflammation induced by psychological stress. LPS doses were adjusted with reference to the magnitude of peripheral cytokine elevation reported in patients, and RS was applied in short single sessions to avoid excessive inflammation. Key ResultsBoth LPS and RS significantly suppressed behavioural sensitization, without inducing other behavioural abnormalities. This suppression was dependent on toll-like receptor-4 activation. LPS-mediated suppression involved cyclooxygenase-2, whereas RS-mediated suppression was linked to the microglia-derived tumour necrosis factor-. LPS did not alter, whereas RS significantly reduced the striatal extracellular dopamine levels. Conclusion and ImplicationsThese findings suggest that acute inflammation suppresses behavioural sensitization through distinct mechanisms depending on the inflammatory trigger, providing a framework for understanding how inflammation may influence psychosis-related processes, with potential relevance to schizophrenia.

The ability to adjust to changing environments (cognitive flexibility) and optimal decision-making are pivotal brain functions that govern successful human behavior. Anxiety and depressive disorders are strongly pervasive psychiatric conditions across the lifespan that profoundly disrupt mechanisms of attention, working memory, and decision-making. Although existing task evidence documents impaired decision-making and flexibility outcomes for both anxiety and depression, there is a growing need to systematically evaluate the role of anxiety and depression and to quantitatively compare the effects of these disorders on these domains. In the present study, we conducted a meta-analysis of anxiety and depression on decision-making and cognitive flexibility. We utilized a random-effects approach, given that a large amount of between-subject heterogeneity was anticipated. Given the scope of this meta-analysis, we used the machine learning tool asReview to more efficiently conduct a meta-analytic search. Across all outcomes, results showed anxiety and depression were associated with reduced cognitive flexibility and decision-making. These effect sizes were then tested for significance using a fixed-effects (plural) model. Subgroup analyses revealed no significant differences between anxiety and depression for either decision-making or flexibility outcomes, consistent with a transdiagnostic perspective. Results are contextualized in light of the biopsychosocial model and potential transdiagnostic factors.

Background: Childhood adversity (CA) is recognized as a distal risk-factor for suicide attempts (SA) in individuals with psychiatric disorders. However, not all individuals with experiences of CA will engage in SA. Contributing to this relationship may be proximal factors such as impulsivity, inward anger and self-aggression. However, these factors are often conceptually blended and measured in different samples. We sought to clarify association among CA and personality factors in persons with SA. Methods: Participants from two studies comprised individuals with a diagnosed psychiatric disorder and history of SA (n= 139) and individuals with depressive disorder (clinical controls, CC; n= 24). We investigated self-reported levels of CA, impulsivity, inward anger, and self-aggression between the SA and CC (pcorr< .012). We tested the relationship among the factors using regression (pcorr<.017) and mediation model (indirect effects, p<.05) within the SA group. Sensitivity models were run controlling for age, gender, symptom severity, trait anger, and externally oriented aggression. Results: SA group had higher impulsivity (pcorr=.067) in a model controlled for age and gender. Other factors did not differ among groups. Within the SA group the analyses revealed positive association among CA and personality factors (pcorr<.06) in basic and model with age and gender, however the association was not specific for internally (self) oriented factors (coefficient comparison, p<.07). Parallel mediation model indicated that CA had indirect effect on self-aggression through impulsivity (p=.001) and to a lesser extent through inward anger (p=.066). Generally, models controlling for cognitive depression symptoms showed less prominent effects (pcorr>.1). Limitations: The study was cross-sectional and did not include behavioral tasks (state) measures of proximal factors. Conclusions: CA and personality factors showed similar severity levels among the SA and CC groups suggesting they may relate to broader psychopathologies, rather than specifically to SA. The association of CA with anger and aggression was unspecific to internally oriented factors indicating the need for more precise measuring instruments developed specifically for individuals with SA. Overall, the study highlights personality factors as being associated with risk in broader vulnerable populations.

Background: The incidence of antidepressant withdrawal reactions in longer-term users and the influence of dosage is insufficiently understood. Objectives: Informed by neuropharmacological models and user surveys, this study examined symptom change during tapering and if increases were specifically associated with reductions below 75% of the minimum effective dose. Design: This was a prospective longitudinal cohort study with seven assessments over six months. Methods: Altogether 32 Swiss adult primary care patients who were on antidepressants for at least six months and in stable remission were assessed at baseline (week 0) before they started tapering and after 2, 4, 6, 8, 16, and 26 weeks. Withdrawal symptoms were measured repeatedly using an adapted version of the Discontinuation-Emergent Signs and Symptoms Scale (DESS) and the main outcome was intra-individual symptom change during intervals. Antidepressant dose was standardized relative to the minimum effective dose in the treatment of depressive and anxiety disorders. Results: Across intervals, reductions below 75% of the minimum effective dose were associated with symptom increases, while reductions above that threshold or no reductions were associated with symptom decreases. After adjusting for potential confounders, the rate of clinically relevant symptom increases contingent on dose reductions below 75% of the minimum effective dose was 33%, as compared to 13% during intervals with no dose reductions (OR=3.2, 1.4 to 7.4). We thus estimated that 60% of the risk of clinically relevant symptom increases was attributable to pharmacological withdrawal effects. The adjusted incidence rates for clinically relevant and severe withdrawal reactions were 32% and 11%, respectively. Conclusions: Consistent with neuropharmacological research findings, we found that antidepressant withdrawal symptoms emerge mostly following reductions below 75% of the minimum effective dose, affecting about one-third of patients. Even small reductions may trigger clinically relevant withdrawal reactions in this lowest dose-range, stressing the need for personalized tapering plans.

Mental illness poses a substantial global burden, yet existing psychotherapies and psychopharmacologies often produce limited outcomes. Psychedelic assisted therapies have emerged as potential transdiagnostic interventions. In particular, 3,4 methylenedioxymethamphetamine assisted therapy (MDMA AT) has generated interest for its rapid psychological effects and potential to enhance psychotherapy outcomes. However, the incremental efficacy of MDMA AT relative to control interventions across transdiagnostic outcomes remains unclear. Further, there have been emerging concerns regarding harm reporting quality in MDMA AT clinical trials. We conducted a systematic review and meta analysis of MDMA AT randomized controlled trials. Eleven publications representing eight controlled trials with 10 analyzed subgroups (n = 295 participants) were included in meta-analyses. Two additional secondary publications were included for harm reporting syntheses (k = 13 total). Across 114 extracted effect sizes, MDMA AT demonstrated a significant moderate-to-large incremental reduction in psychopathology relative to controls (g = 1.03, 95% CI [0.46, 1.60]), though heterogeneity was high (I squared = 76%). Incremental effects were larger versus inert placebos (g = 1.27) than active controls (g = 0.75). Symptom specific analyses indicated strong incremental effects for trauma reduction (g=1.46 [95% CI: 0.67, 2.25]) and smaller non-significant effects for depression (g=0.51 [95% CI: -0.06, 1.08]). Harm reporting quality synthesis showed only 23% of publications met high-quality reporting standards. Overall, MDMA AT demonstrates potential transdiagnostic efficacy, but small samples, confounding factors, and mediocre harm reporting highlight the need for larger more transparent clinical trials.

BackgroundA high proportion of autistic people receive off-license antipsychotic medication, often in the absence of a mental illness, primarily for behaviours that challenge, which is a public health concern. Although meta-analyses have been published recently, there is a lack of a comprehensive network meta-analysis to inform clinicians about the relative efficacy and safety of antipsychotic medications. AimsTo conduct a network meta-analysis of available RCTs of antipsychotic medications involving autistic participants to assess the relative efficacy of different antipsychotics and their adverse effects. MethodWe searched seven databases and hand-searched ten relevant journals. Two authors independently screened titles, abstracts, and full papers, extracted data, and assessed their quality. ResultsWe analysed data from 22 RCTs involving 1562 autistic people. The largest mean difference with 95% confidence interval in the Aberrant Behaviour Checklist-Irritability (ABC-I) score compared with placebo was from the combined intervention with risperidone and parent training: -11.16 (-15.13, -7.18), followed by risperidone: -7.59 (-9.22, -5.95), and aripiprazole: -5.59 (-7.18, -4). The largest effect on Clinical Global Impression-Improvement (CGI-I) scores was from risperidone, 7.65 (2.17, 27.04), followed by aripiprazole, 7.02 (1.92, 25.72), compared with placebo. Risperidone (4; 1.57, 10.21) and aripiprazole (2.77; 1.20, 6.39) had significantly higher odds ratios for adverse effects, but aripiprazole showed the least weight gain. ConclusionsCombined parent training and risperidone followed by risperidone and aripiprazole showed the best effects on the ABC-I score, whereas risperidone and aripiprazole showed the greatest effect on the CGI-I score. However, risperidone and aripiprazole showed significantly increased adverse effects.

Hoarding disorder (HD) affects approximately 2-3% of adults and is associated with substantial functional disability and limited access to evidence-based care. The aim of the current analysis was to examine the naturalistic effectiveness of therapist-delivered video cognitive-behavioral therapy (CBT) for HD in a large real-world sample, and to characterize individual-level treatment response, time-to-response, and moderators of outcome. This retrospective, observational analysis examined clinical data from 305 adults diagnosed with HD who received therapist-delivered video CBT through an online specialty therapy platform between September 2021 and February 2026. Hoarding symptom severity was assessed using the Hoarding Rating Scale-Self Report (HRS-SR). Linear mixed models examined symptom change from baseline to three timepoints: session 10, session 20, and each patient's final session. HRS-SR scores decreased from M = 22.4 (SD = 7.6) at baseline to M = 16.4 (SD = 8.2) at final session (Hedges' g = 0.81, 95% CI: 0.68-0.94). By the final session, median percent improvement was 25.0% [IQR: 3.0-46.7%]. A total of 39.3% of patients achieved [&ge;]35% HRS-SR reduction, 27.4% of patients who began above the clinical threshold achieved remission, 36.4% demonstrated reliable improvement, and 22.9% of eligible patients achieved clinically significant change. Among patients who achieved and maintained [&ge;]35% reduction through their final session (n = 120), median time to first response was session 9, with 54.2% responding within 10 sessions. Analyses of secondary outcomes showed significant improvements in clutter severity, depressive and anxiety symptoms, stress, quality of life, and functional disability (Hedges' g = 0.21-0.47). Greater baseline severity, more sessions, and longer treatment duration significantly moderated outcomes; prior OCD treatment history did not. Findings suggest that therapist-delivered video CBT for HD, delivered remotely in a real-world setting, produces outcomes consistent with controlled trials and may be a clinically effective and scalable approach for a condition historically underserved by mental health systems.

Background: Low-dose levetiracetam is under investigation as a potential treatment for slowing Alzheimer's Disease progression. This study tests whether levetiracetam enhances executive function in mid-age adults, and whether drug effects differ by Apolipoprotein e4 (APOE4+) genetic risk status. Methods: Fifty-eight adults (aged 45-65 years; 27 APOE33; 31 APOE4+) participated in a double-blind, placebo-controlled study of low-dose levetiracetam (125mg bidaily for two-weeks). At the end of each treatment phase, participants completed a switch-inhibition task. Results: Mid-age APOE4+ carriers were significantly slower and showed a greater cost of increasing executive demand than APOE33 individuals. Response times were quicker under levetiracetam, with increased benefits reported in APOE33 individuals, at younger ages, and in individuals with reduced levels of plasma-based biomarkers. Levetiracetam selectively benefitted accuracy in APOE33 individuals. Conclusion: Low-dose levetiracetam enhances executive function in midlife, particularly in individuals at lower risk of Alzheimer's Disease based on age, APOE4 genotype, and proxies of neuropathology.

Background: Participants in the ReINVEST randomised placebo-controlled trial of sertraline, conducted among men with high trait impulsivity and histories of violent offending, received structured clinical contact throughout the trial, including psychiatric assessments, nursing consultations, crisis support, and referrals to mental health and external services. We estimated the effect of placebo trial participation, compared with non-participation after baseline and single-blind run-in, on violent and domestic-violence reoffending. Methods: This prespecified secondary analysis included men from the ReINVEST trial pathway who completed baseline assessment and entered the single-blind run-in phase but did not proceed to randomisation, to inform the counterfactual. Violent and domestic-violence offences were identified from linked administrative records over 12- and 24-month follow-up periods. The adjusted difference in offending was estimated using two independent analytical approaches accounting for baseline differences. Additional analyses examined whether the effect varied by baseline clinical and criminal-history characteristics, whether pre-randomisation external referrals explained selection into placebo participation, and whether post-randomisation external referrals accounted for any part of the estimated effect. Results: Placebo trial participation was associated with lower offending across both outcome domains and follow-up periods. Placebo-standardised mean count differences for violent offending were -0.19 (95% confidence interval [CI] -0.38, -0.04) at 12 months and -0.22 (95% CI -0.51, -0.05) at 24 months. Corresponding differences for domestic-violence offending were -0.37 (95% CI -0.81, -0.14) at 12 months and -0.49 (95% CI -0.92, -0.22) at 24 months. The association was more apparent among men with a documented psychiatric history and, for domestic-violence offending, among those with higher baseline anger, irritability and aggression. Pre-randomisation referrals did not explain selection into placebo participation or materially alter the estimates. Post-randomisation referrals were observed in both groups, remained more common in the placebo group, and did not account for the observed association. Conclusion: Placebo participation in this trial involved sustained clinical contact and psychosocial support beyond exposure to inactive medication, and these non-pharmacological components may have contributed to lower reoffending. In placebo-controlled trials involving populations with high psychiatric morbidity and limited continuity of coordinated care, the clinical content of placebo participation should be explicitly characterised in trial design and interpretation.

Current treatments for opioid use disorder (OUD) have major barriers to access. As such, researching new potential therapies for OUD is important to public health. Previous research has implicated glucagon-like peptide-1 (GLP-1) receptor agonists in decreasing the use of addictive substances by animals. In this study, female Wistar rats (N=32) were surgically implanted with jugular catheters and trained to self-administer fentanyl at a fixed-ratio 1 (FR1) schedule of reinforcement for 21 sessions under short- (ShA; 1 hour) or long-access (LgA; 8 hours) conditions. Next, the animals received injections of semaglutide (0.1 mg/kg, s.c.) or saline (0.9% NaCl, s.c.) prior to another FR1 session. The animals underwent a progressive ratio (PR) schedule of reinforcement while receiving saline (i.v.) or fentanyl (0.625-10 {micro}g/kg/inf, i.v.) and semaglutide (0.1 mg/kg, s.c.) or saline (s.c.). Next, the animals underwent a semaglutide (0-0.1 mg/kg, s.c.) dose response procedure at FR1 and a single dose of fentanyl (2.5 {micro}g/kg/inf, i.v.). Following drug discontinuation, spontaneous locomotor activity and withdrawal-like symptoms were measured. Semaglutide dose-dependently decreased fentanyl rewards under ShA and LgA conditions (p<0.05). Under a PR, semaglutide significantly decreased breakpoint (p<0.05), suggesting semaglutide decreases motivation to self-administer fentanyl. Semaglutide-treated ShA animals displayed significantly less withdrawal-like behavior (p<0.05) but not LgA animals. Overall, these findings suggest semaglutide may modulate motivation to seek opioid reward and could be useful in the development of pharmacotherapies to address OUD.

Subthreshold depression is associated with significant functional impairment and elevated risk of major depressive disorder. A negative self-concept may disrupt the implicit positive association evoked by ones own face, impairing incidental encoding of self-relevant information. Whether subthreshold depression involves a selective deficit in encoding self-face identity remains unclear. The attribute amnesia paradigm is well suited to address this question because it can dissociate attentional selection from working memory encoding. Using this paradigm, we examined the issue across two experiments. Experiment 1 employed nonsocial stimuli (animal drawings) and confirmed an intact attribute amnesia effect in subthreshold depression (n = 30) comparable to healthy controls (n = 30), ruling out a generalized encoding deficit. Experiment 2 replaced targets with faces (self or other) and revealed a selective enhancement of the attribute amnesia effect for self-face identity in subthreshold depression. Specifically, on the surprise trial, accuracy for self-face identity dropped to near-chance levels in the subthreshold depression group, whereas no such deficit emerged for other-faces or in controls. Encoding recovered rapidly once explicit memory expectations were introduced, indicating intact basic encoding capacity. These findings suggest that subthreshold depression is associated with a specific impairment in incidentally encoding self-face identity. This impairment likely stems from a negative self-concept that weakens self-face salience under incidental encoding conditions. By capturing this selective encoding failure, the present study reveals that the self-processing deficit in subthreshold depression can arise at the gating stage between attention and working memory consolidation.

Background: Aberrations in neuro-immune, metabolic, and oxidative stress (NIMETOX) pathways are implicated in major depressive disorder (MDD). First-episode simple dysmood disorder (FE-SDMD) without metabolic syndrome offers a unique model to investigate early lipid alterations underlying NIMETOX pathophysiology. Methods: Plasma samples were collected from 88 university students (44 FE-SDMD, 44 healthy controls). Participants underwent comprehensive psychiatric and psychological assessments, including adverse childhood experiences (ACEs), negative life events (NLEs), depression, anxiety, suicidal behaviors, and insomnia. Untargeted lipid profiling was performed using LC-QTOF-MS, while indices of oxidative and nitrosative stress (ONS) and lecithin-cholesterol acyltransferase (LCAT) activity were assessed. Data was analyzed using machine learning approaches with recursive feature elimination and cross-validation. Results: FE-SDMD was characterized by increased ceramides (CER), diacylglycerides (DAG), triacylglycerides (TG), sphingomyelins (SM), bis-monoacylglycerol phosphates (BMP), cholestone, and fatty-acyl amino acids (FAAA). DAG, CER, and BMP were the strongest predictors of depression severity and physiosomatic symptoms, whereas cholestone, CER, and SM predicted suicidal behaviors. These lipid modules, together with lowered LCAT and increased ONS, explained substantial variance in depression severity (46.4%), physiosomatic symptoms (42.4%), cognitive-affective symptoms (37.9%), suicidal behaviors (30.1%), insomnia (32%), and anxiety (19.5%). ACEs and NLEs were strongly associated with CER (p<0.001), DAG (p<0.01), and cholestone (p<0.01). Conclusion: Early-stage MDD is characterized by distinct lipid dysregulations linked to psychosocial stress exposure, oxidative and nitrosative stress, and an indicant of impaired reverse cholesterol transport. These lipid modules may serve as early biomarkers and therapeutic targets in vulnerable populations.

Background: Hydrogen sulfide (H2S) is an endogenous gasotransmitter synthesised in the central nervous system (CNS) primarily by cystathionine {beta}-synthase (CBS) and cystathionine {gamma}-lyase (CSE). Pre-clinical studies consistently implicates H2S deficiency in the pathophysiology of depression through disruption of synaptic plasticity, neuroinflammation, oxidative stress, and brain-derived neurotrophic factor (BDNF) signalling. Yet, we still lack direct clinical evidence quantifying circulating H2S in patients with Major Depressive Disorder (MDD), particularly from South Asian populations. In this study, we measured serum H2S levels in drug-naive patients with MDD and compared them with healthy controls at a tertiary care center in eastern India. We examined the associations between serum H2S and depression severity as assessed by the 17-item Hamilton Depression Rating Scale (HAM-D-17). This institution-based, cross-sectional analytical study was conducted at North Bengal Medical College and Hospital (NBMCH), West Bengal, India, over 12 months. Fifty drug-naive patients fulfilling DSM-5 criteria for MDD and fifty age- and sex-matched healthy controls were enrolled by consecutive sampling. We quantified serum H2S using the spectrophotometric methylene blue method and depression severity was assessed using HAM-D-17. Statistical analyses included independent-samples t-test, chi-square test, and linear regression. Serum H2S was markedly and significantly lower in MDD patients (0.068 {+/-} 0.044 {micro}mol/L) compared with healthy controls (0.524 {+/-} 0.272 {micro}mol/L; p < 0.001), representing an approximately 7.7-fold reduction. HAM-D-17 scores were significantly higher in MDD patients (28.94 {+/-} 12.78) than in controls (3.96 {+/-} 2.31; p < 0.001). Linear regression across the combined cohort revealed a significant negative association between serum H2S and HAM-D score (R{superscript 2} = 0.287; y = 24.64 - 26.84x; p < 0.001), indicating that higher serum H2S was associated with lower depression severity. Within the MDD group alone, the regression was weak (R{superscript 2} = 0.061), consistent with a floor effect. Within the control group alone, the regression was strong (R{superscript 2} = 0.772). No significant associations were found between serum H2S and any sociodemographic variable in either group. Drug-naive MDD patients exhibited substantially reduced serum H2S levels compared with healthy controls, and lower H2S was associated with greater depression severity. These findings provide direct clinical evidence from an Indian population supporting the H2S deficiency hypothesis of depression and suggest that the CBS/CSE-H2S axis may represent a novel biomarker and therapeutic target in MDD. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/26352330v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1ce64f6org.highwire.dtl.DTLVardef@1465ca2org.highwire.dtl.DTLVardef@6bba64org.highwire.dtl.DTLVardef@9a1411_HPS_FORMAT_FIGEXP M_FIG C_FIG

Background: Dissociative experiences encompass a variety of discontinuities in awareness and perception that are elevated in the dissociative disorders and associated with extensive comorbid symptomatology. Accumulating evidence points to developmental trauma and trait responsiveness to verbal suggestions (REVS) as factors that confer risk for severe dissociative symptoms, but they have typically been studied in isolation. This study integrated these measures using prediction modelling to better understand their predictive value for the risk of dissociative psychopathology. Method: 1,104 non-clinical participants completed measures of trauma, dissociation and trait REVS. The predictive model was developed using elastic net logistic regression, internally validated with 10-fold cross-validation, and assessed using receiver operating characteristic (ROC) curve and area under the ROC (AUROC). Variables entered into the model were components of REVS, trauma, age, and their interactions. Results: A dissociative psychopathology at-risk group (7%) was characterised by younger age, greater trauma and elevated REVS, particularly involuntariness during cognitive-perceptual suggestions. The prediction model retained nine of ten predictors, with an AUROC of .77 [95% CI: .73, .82], reflecting good discrimination with moderate sensitivity (78%) but modest specificity (67%). Conclusions: These findings reinforce trauma and trait REVS as risk factors for dissociative psychopathology and demonstrate that they can be integrated in a model that can identify at-risk individuals. Further validation and extension of the model is necessary to improve the identification of individuals at risk for severe dissociative symptomatology and the diagnosis of dissociative disorders with implications for outcome trajectories.

BackgroundEvidence suggests steeper accelerating opioid-related overdose, and non-medical use rates, in middle aged men in recent years compared with younger cohorts. Little is known about whether this is driven by age-related differences in the effects of opioids compared with socio-cultural factors driving non-medical consumption. Rodent models can be useful for dissociating biological from psychosocial factors, however, only minimal evidence exists on the effects of opioids in middle-age rats. ObjectiveTo determine if the anti-nociceptive and rewarding effects of opioids differ between adult and middle-age rats. MethodsFemale and male Wistar rats were obtained in early adulthood and examined across 4 to 11 months of age for nociceptive responses to heroin (0-1.56 mg/kg, s.c.) using a warm-water tail withdrawal assay. Subgroups (N=8 per group) were initiated on intravenous self-administration (IVSA) of heroin at either 5 months or 12 months of age. ResultsAnti-nociceptive effects of heroin did not differ across age. Female rats that initiated IVSA in early adulthood or middle-age obtained significantly more infusions of heroin than male rats of the same age during acquisition, and in dose-substitution under a FR1 schedule. Male, but not female, rats that initiated IVSA in middle age self-administered less heroin then rats that initiated in early adulthood; this was observed in acquisition and in dose-substitution. DiscussionThis study shows that opioid reward is diminished in middle aged male rats. It also found that middle age rats can be used effectively to model opioid-related outcomes, including drug seeking using the IVSA procedure.

Trauma-focused psychotherapies for post-traumatic stress disorder (PTSD) require waking re-engagement with traumatic memories, driving high dropout. We tested whether trauma-linked auditory cues delivered during slow-wave sleep are feasible. Of 13 patients who provided written informed consent, 6 (100% female) completed overnight Sound Exposure during Sleep (SES); none of the adverse events observed during overnight stimulation were judged by the study team to be attributable to the auditory intervention, and slow-wave sleep was preserved. Two sequential protocol versions were used: Version A (n = 2; capped at SUDs 30-40) and a no-ceiling amendment (Version B, n = 4). Post-hoc exploratory analyses (not powered for efficacy) showed Version B reduced subjective distress (mean difference -65.5%, 95% CI -104.2 to -26.7; nominal p = 0.012) and PCL-5 intrusion (-7.0; nominal p = 0.015). Findings are exploratory and require sham-controlled confirmation. Trial registration: jRCT1030230706.

Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are chronic psychiatric disorders that have overlapping symptomology and risk factors, including altered motivation and impulsive behavior. Inescapable exposure to a predator odor stressor (2,3,5-Trimethyl-3-Thiazoline (TMT)) produces PTSD-like symptomology in rats. Individual differences in stress-coping behaviors such as freezing and defensive digging during TMT exposure can predict long-term differences in alcohol-related behaviors and altered neurobiology. Here, we sought to evaluate the relationship between stress coping behavior during TMT exposure and different aspects of decision making. In Experiment 1, male and female rats were trained on an adjusting-amounts delay discounting task, and delay discounting curves were established before and >2 weeks after TMT exposure. In Experiment 2, female rats were trained to self-administer alcohol and sucrose in a concurrent choice procedure. Lever responses and preference for alcohol over sucrose were evaluated before and >2 weeks after TMT exposure, and then motivation for competing reinforcers was evaluated using progressive ratios. Active coping (digging) during TMT exposure was correlated with increased post-TMT impulsive choice (Experiment 1), reduced sucrose lever responses both before and after TMT exposure (Experiment 2), and reduced sucrose lever breakpoint (Experiment 2). Additionally, TMT-exposed rats had increased motivation for both alcohol and sucrose self-administration when available concurrently (Experiment 2). Overall, these findings suggest that behavior prior to and during a stressful experience can predict susceptibility to negative effects on decision making, which may help future studies identify the neurobiology underlying risk for aberrant reward-related behaviors after a traumatic event.

Prader-Willi syndrome (PWS) is a rare multisystemic disorder characterized by obesity, endocrine dysfunctions, and psychiatric comorbidities, which imply frequent use of psychotropic medications. They account for atypical responses to standard dosages of psychiatric drugs. Pharmacogenetics could be part of the reason for this situation, potentially offering a valuable tool for individualized treatment. This study analyzed allelic and phenotypic frequency distributions of five of the main cytochrome P450 enzymes (CYP2D6, CYP2B6, CYP2C19, CYP2C9, CYP3A4) involved in psychiatric drug metabolism in 47 patients with genetically confirmed diagnosis of PWS and compared them to reference frequencies in the general European population. Allelic frequency comparisons between the European reference population and the overall PWS cohort revealed a significant global difference for CYP2B6, with CYP2C19 and CYP2D6 showing trends toward significance. Although no global allelic differences remained significant after false discovery rate correction, post-hoc analyses consistently identified an enrichment of reduced- or non-functional alleles CYP2B619 and CYP2D610 in patients with PWS. Predicted metabolizer phenotype analyses showed a significant shift toward intermediate metabolizers of CYP3A4 in the PWS cohort, with corresponding depletion of normal metabolizers. Subgroup analyses indicated that allelic differences were more pronounced in maternal uniparental disomy and non-deletion subtypes, particularly for CYP2B6, although no significant differences were observed between PWS genetic subtypes. Overall, results imply potential differences in metabolizing activity in PWS patients, and subsequent implications in drug efficacy and tolerability. These results support the idea that pharmacogenetic testing may improve therapeutic decision-making in PWS for psychiatric treatment. Larger studies are needed to confirm these preliminary results.

The TREM2 R47H variant increases the risk of Alzheimers disease (AD), yet its functional impact in aged mouse models remains incompletely understood. We generated a humanized Trem2 R47H knock-in (KI) line on the AppNL-F background and compared it with a Trem2 knockout (KO) line to assess the degree of TREM2 functional impairment. Accumulation of amyloid {beta} 42 and formation of dystrophic neurites were increased in Trem2 KO mice but not in Trem2 R47H KI mice at 18 or 24 months. qPCR and transcriptomic analyses revealed Trem2 KO mice showed deficits in upregulation of microglial genes while Trem2 R47H KI mice showed a response similar to control mice. Differential gene expression analysis identified altered expressions of genes responsible for ER stress/unfolded protein response and intracellular signalling in Trem2 R47H KI mice. Among the differentially expressed genes, Pmel and Gpnmb were or tended to be downregulated in Trem2 R47H KI as well as in Trem2 KO mice indicating their involvement in AD pathogenesis. These results clearly indicate that the TREM2 R47H variant confers a mild, rather than null, effect on microglial alterations during AD development and that Trem2 R47H KI mice should be used to understand pathological mechanism elicited by TREM2. Further identification and characterization of genes differentially expressed in Trem2 R47H KI mice will provide important insights into how the TREM2 risk variant modulates Alzheimers disease-related pathology. HighlightsO_LIExon2-humanized Trem2 R47H knock-in mice are established, which will serve as a platform to study the role of TREM2 in Alzheimers disease development. C_LIO_LITrem2 knockout mice exhibit deficits in clearance of highly aggregated A{beta}42, suppression of dystrophic neurites and regulation of microglial genes in AppNL-F mice, whereas Trem2 R47H knock-in mice do not. C_LIO_LIRNA-seq reveals transcriptional profiles of Trem2 R47H knock-in mice C_LIO_LIqPCR confirms that Gpnmb and Pmel are or tended to be downregulated in Trem2 R47H knock-in mice. C_LIO_LIFindings demonstrate that TREM2 R47H is hypomorphic rather than loss of function. C_LI