Age of onset of obsessive-compulsive disorder differentially affects white matter microstructure.

Previous diffusion MRI studies have reported mixed findings on white matter microstructure alterations in obsessive-compulsive disorder (OCD), likely due to variation in demographic and clinical characteristics, scanning methods, and underpowered samples. The OCD global study was created across five international sites to overcome these challenges by harmonizing data collection to identify consistent brain signatures of OCD that are reproducible and generalizable. Single-shell diffusion measures (e.g., fractional anisotropy), multi-shell Neurite Orientation Dispersion and Density Imaging (NODDI) and fixel-based measures, were extracted from skeletonized white matter tracts in 260 medication-free adults with OCD and 252 healthy controls. We additionally performed structural connectome analysis. We compared cases with controls and cases with early (<18) versus late (18+) OCD onset using mixed-model and Bayesian multilevel analysis. Compared with healthy controls, adult OCD individuals showed higher fiber density in the sagittal stratum (B[SE] = 0.10[0.05], P = 0.04) and credible evidence for higher fiber density in several other tracts. When comparing early (n = 145) and late-onset (n = 114) cases, converging evidence showed lower integrity of the posterior thalamic radiation -particularly radial diffusivity (B[SE] = 0.28[0.12], P = 0.03)-and lower global efficiency of the structural connectome (B[SE] = 15.3[6.6], P = 0.03) in late-onset cases. Post-hoc analyses indicated divergent direction of effects of the two OCD groups compared to healthy controls. Age of OCD onset differentially affects the integrity of thalamo-parietal/occipital tracts and the efficiency of the structural brain network. These results lend further support for the role of the thalamus and its afferent fibers and visual attentional processes in the pathophysiology of OCD.

Maintenance of Wellness in Patients With Obsessive-Compulsive Disorder Who Discontinue Medication After Exposure/Response Prevention Augmentation: A Randomized Clinical Trial.

IMPORTANCE: Serotonin reuptake inhibitors (SRIs) are the only medications approved for obsessive-compulsive disorder (OCD), yet most patients taking SRIs exhibit significant symptoms. Adding exposure/response prevention (EX/RP) therapy improves symptoms, but it is unknown whether patients maintain wellness after discontinuing SRIs. OBJECTIVE: To assess whether patients with OCD who are taking SRIs and have attained wellness after EX/RP augmentation can discontinue their SRI with noninferior outcomes compared with those who continue their SRI therapy. DESIGN, SETTING, AND PARTICIPANTS: A 24-week, double-blind, randomized clinical trial was performed from May 3, 2013, to June 25, 2018. The trial took place at US academic medical centers. Participants included 137 adults with a principal diagnosis of OCD (≥1 year) who were taking an SRI (≥12 weeks), had at least moderate symptoms (defined as Yale-Brown Obsessive-Compulsive Scale [Y-BOCS] score ≥18 points), and received as many as 25 sessions of EX/RP therapy. Those who attained wellness (Y-BOCS score ≤14 points; 103 patients [75.2%]) were study eligible. Data were analyzed from June 29, 2019, to October 2, 2021. INTERVENTION: Participants were randomly assigned either to receive taper to placebo (taper group) or to continue their SRI (continuation group) and monitored for 24 weeks. MAIN OUTCOME AND MEASURES: The Y-BOCS score (range, 0-40 points) was the primary outcome; the Hamilton Depression Rating Scale (HDRS; range, 0-52 points) and the Quality-of-Life Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF; range, 0%-100%) scores were secondary outcomes. Outcomes were assessed at 8 time points by independent evaluators who were blinded to randomization. The taper regimen was hypothesized to be noninferior to continuation at 24 weeks using a 1-sided α value of .05. RESULTS: A total of 101 patients (mean [SD] age, 31.0 [11.2] years; 55 women [54.5%]) participated in the trial: 51 patients (50.5%) in the taper group and 50 patients (49.5%) in the continuation group. At 24 weeks, patients in the taper group had noninferior results compared with patients in the continuation group (mean [SD] Y-BOCS score: taper group, 11.47 [6.56] points; continuation group: 11.51 [5.97] points; difference, -0.04 points; 1-sided 95% CI, -∞ to 2.09 points [below the noninferiority margin of 3.0 points]; mean [SD] HDRS score: taper group, 5.69 [3.84] points; continuation group, 4.61 [3.46] points; difference, 1.08 points; 1-sided 95% CI, -∞ to 2.28 points [below the noninferiority margin of 2.5 points]; mean [SD] Q-LES-Q-SF score: taper group, 68.01% [15.28%]; continuation group, 70.01% [15.59%]; difference, 2.00%; 1-sided 95% CI, -∞ to 6.83 [below the noninferiority margin of 7.75]). However, the taper group had higher rates of clinical worsening (23 of 51 [45%] vs 12 of 50 [24%]; P = .04). CONCLUSIONS AND RELEVANCE: Results of this randomized clinical trial show that patients with OCD who achieve wellness after EX/RP therapy could, on average, discontinue their SRI with noninferior outcomes compared with those who continued their SRI. Those who tapered the SRI had higher clinical worsening rates. Future research should evaluate if SRI half-life alters these rates. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01686087.

Maximizing remission from cognitive-behavioral therapy in medicated adults with obsessive-compulsive disorder.

Practice guidelines for adults with obsessive-compulsive disorder (OCD) recommend augmenting serotonin reuptake inhibitors (SRIs) with exposure and ritual prevention (EX/RP). However, fewer than half of patients remit after a standard 17-session EX/RP course. We studied whether extending the course increased overall remission rates and which patient factors predicted remission. Participants were 137 adults with clinically significant OCD (Yale-Brown Obsessive Compulsive Scale [Y-BOCS] score ≥18) despite an adequate SRI trial (≥12 weeks). Continuing their SRI, patients received 17 sessions of twice-weekly EX/RP (standard course). Patients who did not remit (Y-BOCS ≤12) received up to 8 additional sessions (extended course). Of 137 entrants, 123 completed treatment: 49 (35.8%) remitted with the standard course and another 46 (33.6%) with the extended course. Poorer patient homework adherence, more Obsessive-Compulsive Personality Disorder (OCPD) traits, and the Brain-Derived Neurotrophic Factor (BDNF) Val66MET genotype were associated with lower odds of standard course remission. Only homework adherence differentiated non-remitters from extended course remitters. Extending the EX/RP course from 17 to 25 sessions enabled many (69.3%) OCD patients on SRIs to achieve remission. Although behavioral (patient homework adherence), psychological (OCPD traits), and biological (BDNF genotype) factors influenced odds of EX/RP remission, homework adherence was the most potent patient factor overall.

History of sexual trauma moderates psychotherapy outcome for posttraumatic stress disorder.

BACKGROUND: Moderators of differential psychotherapy outcome for posttraumatic stress disorder (PTSD) are rare, yet have crucial clinical importance. We tested the moderating effects of trauma type for three psychotherapies in 110 unmedicated patients with chronic DSM-IV PTSD. METHODS: Patients were randomized to 14 weeks of prolonged exposure (PE, N = 38), interpersonal psychotherapy (IPT, N = 40), or relaxation therapy (RT, N = 32). The Clinician-Administered PTSD Scale (CAPS) was the primary outcome measure. Moderator candidates were trauma type: interpersonal, sexual, physical. We fit a regression model for week 14 CAPS as a function of treatment (a three-level factor), an indicator of trauma type presence/absence, and their interactions, controlling for baseline CAPS, and evaluated potential confounds. RESULTS: Thirty-nine (35%) patients reported sexual, 68 (62%) physical, and 102 (93%) interpersonal trauma. Baseline CAPS scores did not differ by presence/absence of trauma types. Sexual trauma as PTSD criterion A significantly moderated treatment effect: whereas all therapies had similar efficacy among nonsexually-traumatized patients, IPT had greater efficacy among sexually traumatized patients (efficacy difference with and without sexual trauma: IPT vs. PE and IPT vs. RT P's < .05), specifically in PTSD symptom clusters B and D (P's < .05). CONCLUSIONS: Few studies have assessed effects of varying trauma types on effects of differing psychotherapies. In this exploratory study, sexual trauma moderated PTSD outcomes of three therapies: IPT showed greater benefit for sexually traumatized patients than PE or RT. The IPT focuses on affect to help patients determine trust in their current environments may particularly benefit patients who have suffered sexual assault.

Altered resting state functional connectivity of fear and reward circuitry in comorbid PTSD and major depression.

BACKGROUND: Individuals with comorbid posttraumatic stress disorder and major depressive disorder (PTSD-MDD) often exhibit greater functional impairment and poorer treatment response than individuals with PTSD alone. Research has not determined whether PTSD-MDD is associated with different network connectivity abnormalities than PTSD alone. METHODS: We used functional magnetic resonance imaging (fMRI) to measure resting state functional connectivity (rs-FC) patterns of brain regions involved in fear and reward processing in three groups: patients with PTSD-alone (n = 27), PTSD-MDD (n = 21), and trauma-exposed healthy controls (TEHCs, n = 34). Based on previous research, seeds included basolateral amygdala (BLA), centromedial amygdala (CMA), and nucleus accumbens (NAcc). RESULTS: Regardless of MDD comorbidity, PTSD was associated with decreased connectivity of BLA-orbitalfrontal cortex (OFC) and CMA-thalamus pathways, key to fear processing, and fear expression, respectively. PTSD-MDD, compared to PTSD-alone and TEHC, was associated with decreased connectivity across multiple amygdala and striatal-subcortical pathways: BLA-OFC, NAcc-thalamus, and NAcc-hippocampus. Further, while both the BLA-OFC and the NAcc-thalamus pathways were correlated with MDD symptoms, PTSD symptoms correlated with the amygdala pathways (BLA-OFC; CMA-thalamus) only. CONCLUSIONS: Comorbid PTSD-MDD may be associated with multifaceted functional connectivity alterations in both fear and reward systems. Clinical implications are discussed.

Treatment preferences of psychotherapy patients with chronic PTSD.

OBJECTIVE: Patient treatment preference may moderate treatment effect in major depressive disorder (MDD) studies. Little research has addressed preference in posttraumatic stress disorder (PTSD); almost none has assessed actual patients' PTSD psychotherapy preferences. From a 14-week trial of chronic PTSD comparing prolonged exposure, relaxation therapy, and interpersonal psychotherapy, we report treatment preferences of the 110 randomized patients, explore preference correlates, and assess effects on treatment outcome. METHOD: Patients recruited between 2008 and 2013 with chronic DSM-IV PTSD (Clinician-Administered PTSD Scale [CAPS] score ≥ 50) received balanced, scripted psychotherapy descriptions prerandomization and indicated their preferences. Analyses assessed relationships of treatment attitudes to demographic and clinical factors. We hypothesized that patients randomized to preferred treatments would have better outcomes, and to unwanted treatment worse outcomes. RESULTS: Eighty-seven patients (79%) voiced treatment preferences or disinclinations: 29 (26%) preferred prolonged exposure, 29 (26%) preferred relaxation therapy, and 56 (50%) preferred interpersonal psychotherapy (Cochran Q = 18.46, P < .001), whereas 29 (26%) were disinclined to prolonged exposure, 18 (16%) to relaxation therapy, and 3 (3%) to interpersonal psychotherapy (Cochran Q = 22.71, P < .001). Several baseline clinical variables correlated with treatment preferences. Overall, treatment preference/disinclination did not predict change in CAPS score, treatment response, or dropout. Comorbidly depressed patients receiving unwanted treatment had worse final CAPS scores. CONCLUSION: These exploratory findings are the first relating patients' PTSD psychotherapy preferences to outcome. Despite explanations emphasizing prolonged exposure's greater empirical support, patients significantly preferred interpersonal psychotherapy. Preference subtly affected psychotherapy outcome; depression appeared an important moderator of the effect of unwanted treatment on outcome. Potential biases to avoid in future research are discussed. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00739765.

Exposure and response prevention helps adults with obsessive-compulsive disorder who do not respond to pharmacological augmentation strategies.

OBJECTIVE: Serotonin reuptake inhibitors (SRIs) are a first-line treatment for obsessive-compulsive disorder (OCD). Yet, most patients with OCD who are taking SRIs do not show excellent response. Recent studies show that augmenting SRIs with risperidone benefits a minority of patients. We evaluated the effectiveness of exposure and response prevention (EX/RP) among nonresponders to SRI augmentation with 8 weeks of risperidone or placebo. METHOD: The study was conducted from January 2007 to August 2012. Nonresponders to SRI augmentation with risperidone or pill placebo (N = 32) in a randomized controlled trial for adults meeting DSM-IV-TR criteria for OCD were offered up to 17 twice-weekly EX/RP sessions. Independent evaluators, blind to treatment, evaluated patients at crossover baseline (week 8), midway through crossover treatment (week 12), post-EX/RP treatment (week 16), and follow-up (weeks 20, 24, 28, and 32). The primary outcome was OCD severity, measured with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Secondary outcomes were depression, quality of life, insight, and social functioning. RESULTS: Between crossover baseline and follow-up, nonresponders to SRI augmentation with risperidone or placebo who received EX/RP showed significant reductions in OCD symptoms and depression, as well as significant increases in insight, quality of life, and social functioning (all P < .001). CONCLUSIONS: Exposure and response prevention is an effective treatment for patients who have failed to respond to SRI augmentation with risperidone or placebo. This study adds to the body of evidence supporting the use of EX/RP with patients who continue to report clinically significant OCD symptoms after multiple pharmacologic trials. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00389493.

Is Exposure Necessary? A Randomized Clinical Trial of Interpersonal Psychotherapy for PTSD.

OBJECTIVE: Exposure to trauma reminders has been considered imperative in psychotherapy for posttraumatic stress disorder (PTSD). The authors tested interpersonal psychotherapy (IPT), which has demonstrated antidepressant efficacy and shown promise in pilot PTSD research as a non-exposure-based non-cognitive-behavioral PTSD treatment. METHOD: The authors conducted a randomized 14-week trial comparing IPT, prolonged exposure (an exposure-based exemplar), and relaxation therapy (an active control psychotherapy) in 110 unmedicated patients who had chronic PTSD and a score >50 on the Clinician-Administered PTSD Scale (CAPS). Randomization stratified for comorbid major depression. The authors hypothesized that IPT would be no more than minimally inferior (a difference <12.5 points in CAPS score) to prolonged exposure. RESULTS: All therapies had large within-group effect sizes (d values, 1.32-1.88). Rates of response, defined as an improvement of >30% in CAPS score, were 63% for IPT, 47% for prolonged exposure, and 38% for relaxation therapy (not significantly different between groups). CAPS outcomes for IPT and prolonged exposure differed by 5.5 points (not significant), and the null hypothesis of more than minimal IPT inferiority was rejected (p=0.035). Patients with comorbid major depression were nine times more likely than nondepressed patients to drop out of prolonged exposure therapy. IPT and prolonged exposure improved quality of life and social functioning more than relaxation therapy. CONCLUSIONS: This study demonstrated noninferiority of individual IPT for PTSD compared with the gold-standard treatment. IPT had (nonsignificantly) lower attrition and higher response rates than prolonged exposure. Contrary to widespread clinical belief, PTSD treatment may not require cognitive-behavioral exposure to trauma reminders. Moreover, patients with comorbid major depression may fare better with IPT than with prolonged exposure.

Six-month outcomes from a randomized trial augmenting serotonin reuptake inhibitors with exposure and response prevention or risperidone in adults with obsessive-compulsive disorder.

OBJECTIVE: To compare outcomes after 6-month maintenance treatment of adults diagnosed with obsessive-compulsive disorder (OCD) based on DSM-IV criteria who responded to acute treatment with serotonin reuptake inhibitors (SRIs) augmented by exposure and response prevention (EX/RP) or risperidone. METHOD: A randomized trial was conducted at 2 academic sites from January 2007 through December 2012. In the acute phase, 100 patients on therapeutic SRI dose with at least moderate OCD severity were randomized to 8 weeks of EX/RP, risperidone, or pill placebo. Responders entered the 6-month maintenance phase, continuing the augmentation strategy they received acutely (n = 30 EX/RP, n = 8 risperidone). Independent evaluations were conducted every month. The main outcome was the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). RESULTS: Intent-to-treat analyses indicated that, after 6-month maintenance treatment, EX/RP yielded OCD outcomes that were superior to risperidone (Y-BOCS = 10.95 vs 18.70; t40 = 2.76, P = .009); more patients randomized to EX/RP met response criteria (Y-BOCS decrease ≥ 25%: 70% vs 20%; P < .001) and achieved minimal symptoms (Y-BOCS ≤ 12: 50% vs 5%; P < .001). During maintenance, OCD severity decreased slightly in both conditions (Y-BOCS decrease = 2.2 points, P = .020). Lower Y-BOCS at entry to maintenance was associated with more improvement in both conditions (r38 = 0.57, P < .001). CONCLUSIONS: OCD patients taking SRIs who responded to acute EX/RP or risperidone maintained their gains over 6-month maintenance. Because EX/RP patients improved more during acute treatment than risperidone-treated patients, and both maintained their gains during maintenance, EX/RP yielded superior outcomes 6 months later. The findings that 50% of patients randomized to EX/RP had minimal symptoms at 6-month maintenance, a rate double that of prior studies, suggests that EX/RP maintenance helps maximize long-term outcome. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00389493.

Cognitive-behavioral therapy vs risperidone for augmenting serotonin reuptake inhibitors in obsessive-compulsive disorder: a randomized clinical trial.

IMPORTANCE: Obsessive-compulsive disorder (OCD) is one of the world's most disabling illnesses according to the World Health Organization. Serotonin reuptake inhibitors (SRIs) are the only medications approved by the Food and Drug Administration to treat OCD, but few patients achieve minimal symptoms from an SRI alone. In such cases, practice guidelines recommend adding antipsychotics or cognitive-behavioral therapy consisting of exposure and ritual prevention (EX/RP). OBJECTIVE: To compare the effects of these 2 SRI augmentation strategies vs pill placebo for the first time, to our knowledge, in adults with OCD. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial (conducted January 2007-August 2012) at 2 academic outpatient research clinics that specialize in OCD and anxiety disorders. Patients (aged 18-70 years) were eligible if they had OCD of at least moderate severity despite a therapeutic SRI dose for at least 12 weeks prior to entry. Of 163 who were eligible, 100 were randomized (risperidone, n = 40; EX/RP, n = 40; and placebo, n = 20), and 86 completed the trial. INTERVENTIONS: While continuing their SRI at the same dose, patients were randomized to the addition of 8 weeks of risperidone (up to 4 mg/d), EX/RP (17 sessions delivered twice weekly), or pill placebo. Independent assessments were conducted every 4 weeks. MAIN OUTCOME AND MEASURE: The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) to measure OCD severity. RESULTS: Patients randomized to EX/RP had significantly greater reduction in week 8 Y-BOCS scores based on mixed-effects models (vs risperidone: mean [SE], -9.72 [1.38]; P < .001 vs placebo: mean [SE], -10.10 [1.68]; P < .001). Patients receiving risperidone did not significantly differ from those receiving placebo (mean [SE], -0.38 [1.72]; P = .83). More patients receiving EX/RP responded (Y-BOCS score decrease ≥25%: 80% for EX/RP, 23% for risperidone, and 15% for placebo; P < .001). More patients receiving EX/RP achieved minimal symptoms (Y-BOCS score ≤12: 43% for EX/RP, 13% for risperidone, and 5% for placebo; P = .001). Adding EX/RP was also superior to risperidone and placebo in improving insight, functioning, and quality of life. CONCLUSIONS AND RELEVANCE: Adding EX/RP to SRIs was superior to both risperidone and pill placebo. Patients with OCD receiving SRIs who continue to have clinically significant symptoms should be offered EX/RP before antipsychotics given its superior efficacy and less negative adverse effect profile. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00389493.

Treatment response, symptom remission, and wellness in obsessive-compulsive disorder.

BACKGROUND: Obsessive-compulsive disorder (OCD) is defined both by intrusive, unwanted thoughts, images, or impulses and by repetitive behavioral or mental acts that are often performed to try to alleviate anxiety. The ultimate goal of treatment for OCD is to reduce the symptoms as well as help patients achieve "wellness." Currently, however, there are no widely accepted, empirically supported criteria for determining wellness in OCD. METHOD: Building on previous research, the current study examined the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score that most reliably identified patients who responded to treatment, those who achieved symptom remission, and those who achieved wellness. The current study pooled data from 4 randomized controlled OCD treatment trials (N = 288), which took place between 1990 and 2011 at 2 academic sites. Participants (mean age = 36.8 years) had a primary diagnosis of DSM-IV-TR OCD (mean Y-BOCS score = 25.9). RESULTS: Signal detection analyses showed that a pretreatment-to-posttreatment reduction of ≥ 35% on the Y-BOCS was most predictive of treatment response as defined by the Clinical Global Impressions (CGI)-Improvement scale. A posttreatment Y-BOCS score of ≤ 14 was the best predictor of symptom remission, whereas a score of ≤ 12 was the best predictor of wellness, as defined by symptom remission (defined by the CGI-Severity scale), good quality of life (as measured by the Quality of Life Enjoyment and Satisfaction Questionnaire), and a high level of adaptive functioning (as assessed by the Social Adjustment Scale-Self-Report). Because efficiency (0.86) and specificity (0.88) were highest at the cutoff of ≤ 12, this cutoff score was determined to be the best indicator of wellness. CONCLUSIONS: The present findings support the convergent validity of the Y-BOCS with other measures of well-being (quality of life, adaptive functioning) and highlight the utility of a Y-BOCS score ≤ 12 as a solo indicator of wellness in outcome studies. The use of empirically supported criteria for defining wellness in OCD is recommended to facilitate comparisons across treatment outcome studies and to inform clinical treatment planning. TRIAL REGISTRATION: Pooled data analyzed in this study were from 4 clinical trials, 3 of which are registered at ClinicalTrials.gov (identifiers: NCT00045903, NCT00389493, NCT00316316).

Developmental constraints on behavioural flexibility.

We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

Fecal glucocorticoids reflect socio-ecological and anthropogenic stressors in the lives of wild spotted hyenas.

Our aim was to identify natural and anthropogenic influences on the stress physiology of large African carnivores, using wild spotted hyenas (Crocuta crocuta) as model animals. With both longitudinal data from a single social group, and cross-sectional data from multiple groups, we used fecal glucocorticoids (fGC) to examine potential stressors among spotted hyenas. Longitudinal data from adult members of a group living on the edge of the Masai Mara National Reserve, Kenya, revealed that fGC concentrations were elevated during two periods of social upheaval among adults, especially among younger females; however, prey availability, rainfall, and presence of lions did not influence fGC concentrations among hyenas. Our results suggested that anthropogenic disturbance in the form of pastoralist activity, but not tourism, influenced fGC concentrations among adult male hyenas; rising concentrations of fGC among males over 12 years were significantly correlated with increasing human population density along the edge of the group's home range. As hyenas from this social group were frequently exposed to anthropogenic disturbance, we compared fGC concentrations among these hyenas with those obtained concurrently from hyenas living in three other groups undisturbed by pastoralist activity. We found that fGC concentrations from the undisturbed groups were significantly lower than those in the disturbed group, and we were able to rule out tourism and ecological stressors as sources of variation in fGC among the populations. Thus it appears that both social instability and anthropogenic disturbance, but not the ecological variables examined, elevate fGC concentrations and represent stressors for wild spotted hyenas. Further work will be necessary to determine whether interpopulation variation in stress physiology predicts population decline in groups exposed to intensive anthropogenic disturbance.

Non-invasive measurement of fecal estrogens in the spotted hyena (Crocuta crocuta).

Fecal hormone analysis is a useful tool for frequent, non-invasive sampling of free-living animals. Estrogens fluctuate throughout life among reproductive states in female animals, and intensive repetitive sampling can permit accurate assessment of female reproductive condition. This type of repetitive sampling is difficult in large carnivores, including the spotted hyena (Crocuta crocuta). Patterns of estrogen secretion in captive and free-living hyenas are virtually unknown. Here we present validation of an enzyme-immunoassay to measure fecal estrogen (fE) concentrations in wild and captive spotted hyenas. Results from high-performance liquid chromatography indicate that an antibody specific for estradiol exhibits high immunoreactivity with our extracted samples. Fecal extract displacement curves paralleled our estradiol standard curve within the range of 20-80% antibody binding. Additionally, animals treated with luteinizing hormone-releasing hormone showed a measurable rise in fE concentrations. Finally, once we controlled for effects of time of day of sample collection from wild hyenas, patterns in fE concentrations resembled those in plasma estradiol, including higher levels of fE in mature than immature females, and higher levels of fE during late than early pregnancy. Together, these results suggest that fE concentrations reflect circulating estrogens in spotted hyenas.

Factors regulating the timing of puberty onset in female rhesus monkeys (Macaca mulatta): role of prenatal androgens, social rank, and adolescent body weight.

This study investigated whether prenatal androgen exposure, social rank, and body weight are factors regulating pubertal development in outdoor-housed female rhesus monkeys. Subjects' mothers received injections of testosterone enanthate (20 mg/ wk), flutamide (an androgen receptor blocker, 30 mg/kg twice daily), or vehicle during Gestational Days 35/40-70 (early) or Days 105/110-140 (late). Monitoring of pubertal development began around 28 mo of age during the fall breeding season, with frequent assessment of menstruation, circulating steroids, and weight. Menarche occurred 1.5 mo later in females treated late in gestation than in females treated early in gestation. This short menarche delay occurred in females treated with androgen, flutamide, or vehicle. No effect of prenatal manipulations on first ovulation were found. Social rank was related to first ovulation but not menarche, with low-ranked females less likely than high- or middle-ranked females to ovulate at 2.5 yr than at 3.5 yr of age. Females ovulating early, around 2.5 yr, had higher pubertal body weights and body mass indexes (BMI) than did females ovulating later, suggesting that better nutritional reserves or positive energy balance affect pubertal development. Thus, social rank and likely nutritional status influenced pubertal development in this study. Hormonal manipulations had no detectable effect; instead, handling late in gestation, which may have increased maternal adrenal activity, delayed menarche. This finding contrasts with earlier studies that showed that prenatal androgens delay menarche by 4-6 mo on average. This study supports late gestation as a period of increased sensitivity to environmental insult and demonstrates that multiple factors, including prenatal programming, modulate the specific timing of pubertal events.