Longitudinal analysis of subjective quality of life in schizophrenia: anxiety as the best symptom predictor

We examined the relationships among changes in anxiety, depression, core symptoms of schizophrenia, and subjective quality of life (QL) longitudinally. Fifty-three stabilized outpatients diagnosed with schizophrenia or schizoaffective disorder were assessed for QL and symptoms every 3 months for a period of 1 year. Using mixed effects models, we found that changes in anxiety, as rated on the Brief Psychiatric Rating Scale, were inversely associated with general life satisfaction and satisfaction with many specific domains. These relationships were stronger than the relationships of QL and any other core symptoms of schizophrenia, including depression. Anxiety was also related to some positive and negative symptoms. These findings support the notion that more precise analysis of general psychopathology, and anxiety in particular, is important in clarifying the factors involved in QL in schizophrenia. We explain our findings in the context of current theories of affect and suggest implications for the treatment of schizophrenia.

Quality of life in schizophrenia: contributions of anxiety and depression

A number of studies have demonstrated a strong relationship between quality of life in schizophrenia and general psychopathology measures, and moreover, that the positive, negative, and disorganized symptoms are less related to quality of life. The current investigation examined the relationship between quality of life and symptomatology in 63 stabilized outpatients diagnosed with schizophrenia or schizoaffective disorder. Consistent with other findings, more severe depression, as rated on the Brief Psychiatric Rating Scale (BPRS) was associated with lower general life satisfaction and lower satisfaction with daily living, finances, health, and social life. In addition, higher anxiety ratings on the BPRS were associated with less satisfaction with global quality of life, daily activities, family, health and social relationship, even when controlling for positive symptoms, negative symptoms, or depression. No other symptoms of schizophrenia were as strongly associated with subjective quality of life. Anxiety was also significantly correlated with a number of positive and negative symptoms while depression was substantially less related. These findings, suggest that more precise analyses of general psychopathology, and anxiety in particular, may be necessary to further clarify the factors involved in quality of life in schizophrenia. In addition, these findings suggest future directions for theories of affect and treatment in schizophrenia.

Female marmoset monkeys (Callithrix jacchus) can be identified from the chemical composition of their scent marks

The present study analyzed 42 organic solvent extracts of scent mark pools from five dominant female common marmosets by gas chromatography (GC) and combined GC and mass spectrometry. We determined whether there were qualitative or quantitative differences between the chemical composition of scent marks from individual females. Gas chromatography and mass spectral analysis detected the same 162 chemicals in 86% (36/42) of scent mark pools from five dominant females. This near identical chemical composition of scent marks suggested there were few, if any, qualitative differences between the chemical composition of scent marks from individual females. Instead, quantitative differences in scent may provide the key factor distinguishing individual females. Using the relative concentration of highly volatile chemicals detected by GC in scent marks, linear discriminant analysis classified scent mark pools to their correct donor approximately 91% of the time. Such highly reliable statistical matching of scent to donor suggested that each individual female common marmoset has a unique ratio of highly volatile chemicals in their scent marks which may permit individual identification of females from odors in their scent alone.

Adolescents' knowledge and beliefs about pregnancy: the impact of "ENABL"

Finding effective ways to prevent adolescent pregnancy is a concern of public health officials, educators, social workers, parents, and legislators. Numerous programs exist, but there is debate as to whether it is the specific program itself or other factors that are responsible for participants' successful outcomes. Using a quasi-experimental design, this study sought to determine which factors predicted changes in knowledge and beliefs among middle school students (N = 1,450) after exposure to Postponing Sexual Involvement (PSI), the curricular component of Education Now and Babies Later (ENABL), a pregnancy prevention program. It was found that the single most important predictor of improvement in knowledge and beliefs about pregnancy prevention was PSI itself, not background variables. The findings contradict some of the previous studies on factors impacting teenage pregnancy and lend support for the continued examination of ENABL as a promising component of pregnancy prevention efforts.

Oxytocin responsivity in mothers of infants: a preliminary study of relationships with blood pressure during laboratory stress and normal ambulatory activity

The neuropeptide oxytocin (OT) enhances maternal behavior and decreases blood pressure (BP) and stress responses in animals. Thus, the relationship of OT responsivity to BP in 14 breast- and 11 bottle-feeding mothers of infants was examined. Laboratory BP was assessed during baseline, speech preparation, active speech, and recovery on 2 days, 1 in which baseline and speech were separated by 10 min of baby holding and the other by no baby contact. Systolic BP reactivity to speech was lower after baby contact. Plasma OT change from baseline to speech after baby contact defined OT increase, minimal OT change, and OT decrease groups. OT increase mothers were primarily breast-feeders, and they had lower BP throughout both stress sessions and after baby feeding at home than OT decrease mothers, who also had greater BP reactivity to preparation and recovery. These results suggest that oxytocin has antistress and BP-lowering effects in humans.

Insight, symptoms, and neurocognition in schizophrenia and schizoaffective disorder

There are conflicting reports in the literature regarding the relationships among impaired insight, symptoms, and neurocognition in schizophrenia. The inconsistent findings likely reflect the multidimensionality of insight in this population, along with variations in study design. We examined 46 individuals with chronic schizophrenia or schizoaffective disorder who were recently discharged from an inpatient unit. Insight was operationalized as awareness of having a mental disorder and awareness and attribution of both current and past symptoms. Positive, negative, disorganized, and depression symptoms were rated, and a neurocognition battery, including measures of visual processing, memory, visuo-spatial ability, and executive functions, was administered. Poor awareness of symptoms was moderately associated with core schizophrenia symptoms, and higher levels of depression were strongly associated with good awareness. Symptom misattribution, more so than symptom unawareness, was associated with deficits in frontal lobe functioning. Finally, different patterns of associations between symptoms, neurocognition, and insight were noted for current symptoms versus past symptoms. The data suggest that insight deficits in schizophrenia are multidimensional, and that investigators should pay careful attention to the choice of measures as well as to phase of illness characteristics in future studies.

True recurrence vs. new primary ipsilateral breast tumor relapse: an analysis of clinical and pathologic differences and their implications in natural history, prognoses, and therapeutic management

PURPOSE

The purpose of this study was to classify all ipsilateral breast tumor relapses (IBTR) in patients treated with conservative surgery and radiation therapy (CS+RT) as either new primary tumors (NP) or true local recurrences (TR) and to assess the prognostic and therapeutic implications of this classification.

METHODS AND MATERIALS

Of the 1152 patients who have been treated at Yale-New Haven Hospital before 1990, 136 patients have experienced IBTR as their primary site of failure. These relapses were classified as either NP or TR. Specifically, patients were classified as NP if the recurrence was distinctly different from the primary tumor with respect to the histologic subtype, the recurrence location was in a different location, or if the flow cytometry changed from aneuploid to diploid. This information was determined by a detailed review of each patient's hospital and/or radiotherapy record, mammograms, and pathologic reports.

RESULTS

As of 2/99, with a mean follow-up of 14. 2 years, the overall ipsilateral breast relapse-free rate for all 1152 patients was 86% at 10 years. Using the classification scheme outlined above, 60 patient relapses were classified as TR, 70 were classified as NP and 6 were unable to be classified. NP patients had a longer mean time to breast relapse than TR patients (7.3 years vs. 3.7 years, p < 0.0001) and were significantly younger than TR patients (48.9 years vs. 54.5 years, p < 0.01). Patients developed both TR and NP at similar rates until approximately 8 years, when TR rates stabilized but NP rates continued to rise. By 15 years following original diagnosis, the TR rate was 6.8% compared to 13.1% for NP. Of the patients who had been previously tested for BRCA1/2 mutations, 17% (8/52) had deleterious mutations. It is noteworthy that all patients with deleterious mutations had new primary IBTR, while patients without deleterious mutations had both TR and NP (p = 0.06). Ploidy was evenly distributed between TR and NP but NP had a significantly lower S phase fraction (NP 13.1 vs. TR 22.0, p < 0.05). The overall survival following breast relapse was 64% at 10 years and 49% at 15 years. With a mean follow-up of 10.4 years following breast relapse, patients with NP had better 10-year overall survival (TR 55% vs. NP 75%, p < 0.0001), distant disease-free survival (TR 41% vs. NP 85%, p < 0.0001), and cause-specific survival (TR 55% vs. NP 90%, p < 0.0001).

CONCLUSION

It appears that a significant portion of patients who experience ipsilateral breast tumor relapse following conservative surgery and radiation therapy have new primary tumors as opposed to true local recurrences. True recurrence and new primary tumor ipsilateral breast tumor relapses have different natural histories, different prognoses, and, in turn, different implications for therapeutic management.

Neuropathic pain

Neuropathic pain is a distressing, poorly understood and under-treated condition. In this review we seek to examine the definition and classification of neuropathic pain, summarize clinically important underlying mechanisms, outline current management strategies and look at future directions for research and therapy.

Oxytocin responsivity in mothers of infants: a preliminary study of relationships with blood pressure during laboratory stress and normal ambulatory activity

The neuropeptide oxytocin (OT) enhances maternal behavior and decreases blood pressure (BP) and stress responses in animals. Thus, the relationship of OT responsivity to BP in 14 breast- and 11 bottle-feeding mothers of infants was examined. Laboratory BP was assessed during baseline, speech preparation, active speech, and recovery on 2 days, 1 in which baseline and speech were separated by 10 min of baby holding and the other by no baby contact. Systolic BP reactivity to speech was lower after baby contact. Plasma OT change from baseline to speech after baby contact defined OT increase, minimal OT change, and OT decrease groups. OT increase mothers were primarily breast-feeders, and they had lower BP throughout both stress sessions and after baby feeding at home than OT decrease mothers, who also had greater BP reactivity to preparation and recovery. These results suggest that oxytocin has antistress and BP-lowering effects in humans.

Multiregion contact systems for modelling STD epidemics

This paper elicits properties of some multiregional contact systems for STD infections that are intended to assist the understanding of disease control strategies. To this end, a space-time SIS model is described that maintains the symmetry of contact that is inherent in the formation of sexual partnerships. It is demonstrated how the characteristic stability conditions of this model provide a framework for understanding the potential for sustained transmission after the introduction of the agent into a given region. Then, more complex SI specifications are derived that are particularly relevant to the transmission of HIV. These extensions include the introduction of alternative modes of travel and behavioural adaptations made in response to the circulation of HIV and the incidence of AIDS. The discussion suggests some additions to the systems that might enhance their applicability in practice.

Presenilin 1 regulates pharmacologically distinct gamma -secretase activities. Implications for the role of presenilin in gamma -secretase cleavage

Presenilins (PSs) are polytopic membrane proteins that have been implicated as potential therapeutic targets in Alzheimer's disease because of their role in regulating the gamma-secretase cleavage that generates the amyloid beta protein (Abeta). It is not clear how PSs regulate gamma-secretase cleavage, but there is evidence that PSs could be either essential cofactors in the gamma-secretase cleavage, gamma-secretase themselves, or regulators of intracellular trafficking that indirectly influence gamma-secretase cleavage. Using presenilin 1 (PS1) mutants that inhibit Abeta production in conjunction with transmembrane domain mutants of the amyloid protein precursor that are cleaved by pharmacologically distinct gamma-secretases, we show that PS1 regulates multiple pharmacologically distinct gamma-secretase activities as well as inducible alpha-secretase activity. It is likely that PS1 acts indirectly to regulate these activities (as in a trafficking or chaperone role), because these data indicate that for PS1 to be gamma-secretase it must either have multiple active sites or exist in a variety of catalytically active forms that are altered to an equivalent extent by the mutations we have studied.

Behavioral discrimination between circumgenital odor from peri-ovulatory dominant and anovulatory female common marmosets (Callithrix jacchus)

Social peer groups of callitrichid monkeys [marmosets and tamarins] exhibit intrasexual dominance hierarchies in captivity. This laboratory study employed two-choice behavioral discrimination bioassys to test the hypothesis that scent from female common marmosets contains chemical cues that permit discrimination between dominant females in the periovulatory versus luteal phase of the ovarian cycle and females holding dominant versus subordinate status. When scent from only dominant females was presented, marmosets directed significantly greater amounts of investigatory behavior toward peri-ovulatory scent versus scent collected during the luteal phase of the ovarian cycle. Animals of both sexes demonstrated significant discriminatory behavior between scent deposited by dominant versus subordinate females, but only when the dominant female was in the peri-ovulatory phase of the ovarian cycle. Test animals directed equal amounts of investigative behavior toward scent from luteal-phase dominant females and subordinate females. Female test subjects deposited significantly more scent marks over presented scents than did male subjects, particularly when the scent had been donated by a peri-ovulatory female. Chemical odors specific to the periovulatory and luteal phases of the ovarian cycle may play a role in mediating behavioral interactions among marmosets.

Social and reproductive conditions modulate urinary cortisol excretion in black tufted-ear marmosets (Callithrix kuhli)

The links between psychosocial stress, social status, reproductive function, and urinary cortisol were assessed in social groups of black tufted-ear marmosets (Callithrix kuhli). Urinary cortisol excretion was monitored in cases of intrafamily conflict ("sibling fights") and in daughters in four distinct social contexts: in the family group, while housed singly or in same-sex pairs, and while paired with a male pairmate. Cortisol excretion was elevated in participants in intra-family conflict on the day of and the day following the conflict, relative to concentrations a week prior to or following the conflict. Daughters in natal family groups had concentrations of cortisol that did not differ from reproductively active adult females. This finding held for daughters who were either anovulatory or undergoing ovulatory cycles while in the natal family group. Natal family members and male pairmates exerted buffering effects on levels of activity in the hypothalamic pituitary adrenal axis (HPA) in female C. kuhli. Placing females in solitary housing led to significantly increased cortisol excretion. In the 2 months subsequent to pairing with a male partner, excreted cortisol concentrations in females declined significantly. Daughters removed from their natal family group and housed with a sister did not exhibit increased cortisol levels. These data reveal that activity in the (HPA) axis in marmosets is sensitive to psychosocial stressors, and that urinary cortisol can provide a useful quantitative measure of HPA reactivity. As in other callitrichids, delayed breeding in daughters and reproductive anomalies in C. kuhli appear to be mediated by mechanisms other than elevated HPA activity.

Pharmacokinetics of dopamine in healthy male subjects

BACKGROUND

Dopamine is an agonist of alpha, beta, and dopaminergic receptors with varying hemodynamic effects depending on the dose of drug being administered. The purpose of this study was to measure plasma concentrations of dopamine in a homogeneous group of healthy male subjects to develop a pharmacokinetic model for the drug. Our hypothesis was that dopamine concentrations can be predicted from the infusion dose using a population-based pharmacokinetic model.

METHODS

Nine healthy male volunteers aged 23 to 45 yr were studied in a clinical research facility within our academic medical center. After placement of venous and arterial catheters, dopamine was infused at 10 microg x kg(-1) x min(-1) for 10 min, followed by a 30-min washout period. Subsequently, dopamine was infused at 3 microg x kg(-1) x min(-1) for 90 min, followed by another 30-min washout period. Timed arterial blood samples were centrifuged, and the plasma was analyzed by high-performance liquid chromatography. Mixed-effects pharmacokinetic models using NONMEM software (NONMEM Project Group, University of California, San Francisco, CA) were used to determine the optimal compartmental pharmacokinetic model for dopamine.

RESULTS

Plasma concentrations of dopamine varied from 12,300 to 201,500 ng/l after 10 min of dopamine infusion at 10 microg x kg(-1) x min(-1). Similarly, steady-state dopamine concentrations varied from 1,880 to 18,300 ng/l in these same subjects receiving 3-microg x kg(-1) x min(-1) infusions for 90 min. A two-compartment model adjusted for body weight was the best model based on the Schwartz-Bayesian criterion.

CONCLUSIONS

Despite a homogeneous population of healthy male subjects and weight-based dosing, there was 10- to 75-fold intersubject variability in plasma dopamine concentrations, making standard pharmacokinetic modeling of less utility than for other drugs. The data suggest marked intraindividual and interindividual variability in dopamine distribution and/or metabolism. Thus, plasma dopamine concentrations in patients receiving dopamine infusion at identical rates may vary profoundly. Our data suggest that dosing dopamine based on body weight does not yield predictable blood concentrations.

Ethical decision making among family therapists and individual therapists

In this study, we investigated the ethical decision making of 30 individual and 30 family therapists in order to detect the types of decision making used by practicing therapists. Informants responded to three ethical dilemmas. Two of the situations were hypothetical. The third dilemma was a situation the informant had experienced in practice. Each interview was assessed for decision-making style, using content analysis. Kohlberg's justice reasoning and Gilligan's care reasoning provided the conceptual foundations for this analysis. The results suggest that both family and individual therapists prefer care reasoning on all dilemma types. There was significantly more care reasoning demonstrated on the personal dilemma than on the hypothetical dilemmas. Characteristics of informants did not provide clear explanations for the differences found in reasoning.

Interactive risk factors for treatment adherence in a chronic psychotic disorders population

This study identified the unique and primary contributions of several concurrent risk factors for poor adherence to treatment recommendations in a clinic population of individuals with chronic psychotic disorders, i.e. 48% had DSM-IV diagnoses of schizoaffective disorder, 38% had schizophrenia, paranoid type, 12% had schizophrenia, undifferentiated type, and 2% had affective disorder with psychotic features. The target cohort consisted of 87 consecutive admissions to a continuing day treatment program. As part of a services-oriented quality assurance program, clinical staff completed rating scales for all patients. These included the BASIS-32 rating scale, which consisted of the following five subscales: psychosis; depression/anxiety; impulsive/addictive behavior; relation to self and others; and daily living and role functioning, and the Working Alliance Inventory-short form (therapist version), which consisted of the following three subscales: goal; task; and bond. These data were used to identify risk factors that weaken a patient's adherence to medication and non-medication treatment during the first 2 weeks of treatment in the clinic. Medication treatment consisted of both typical and atypical neuroleptic medications, with most patients being on multiple medications. Correlational analyses suggested that many of the risk factor variables were significantly associated with poor treatment adherence. Regression analyses suggested that the degree of psychoticism was most strongly associated with poor adherence to medication treatment and that difficulties relating to self and others were the strongest predictor of poor adherence to non-medication treatment. A large-sample services research design such as this can begin to determine patterns of associations between previous identified risk factors and poor treatment adherence in individuals with chronic psychotic disorders.

Symptoms and neurocognition as rate limiters in skills training for psychotic patients

OBJECTIVE

This study aimed to replicate findings that neurocognitive capacity in schizophrenia is more predictive of acquisition of social skills than are symptoms.

METHOD

Thirty-two hospitalized patients with chronic psychotic disorders were randomly assigned to community reintegration skills training or supportive group therapy. Neurocognitive functioning was assessed before treatment, and symptoms and skill levels were measured before and after treatment.

RESULTS

The skills training group showed significantly greater skill acquisition. In a regression model, skill acquisition was predicted by group membership and verbal memory capacity and not by symptoms.

CONCLUSIONS

With methodological advances, the authors replicated findings regarding the importance of neurocognition in determining treatment outcome in schizophrenia.

Ethanol feeding selectively impairs the spreading of rat perivenous hepatocytes on extracellular matrix substrates

BACKGROUND

Hepatocytes require attachment and subsequent spreading on an extracellular matrix for their proper growth, function and survival. Our previous studies have shown that ethanol feeding selectively impairs perivenule hepatocyte attachment to various extracellular matrices. This study was undertaken to determine whether zonal differences in hepatocyte spreading in response to ethanol feeding occurs and to ascertain the influence of ethanol consumption on the zonal expression of the beta1 subunit of integrins, which are the major surface receptors responsible for matrix binding and subsequent interactions.

METHODS

Hepatocytes from the perivenous and periportal regions of the liver were isolated by digitonin/collagenase perfusion from rats that were pair-fed for 2 to 3 weeks with a liquid diet containing either ethanol or isocaloric carbohydrate. The ability of perivenous and periportal hepatocytes to spread on plates coated with either type IV collagen, laminin, fibronectin or polylysine was determined. In addition, the isolated cells were used for the analysis of total cellular and surface beta1 integrin expression.

RESULTS

With all of the matrix substrates tested, the spreading of perivenous hepatocytes isolated from the ethanol-fed animals was markedly impaired, while the spreading of periportal hepatocytes was essentially unaffected by ethanol feeding. Both the total cellular as well as the surface expression of the beta1 integrin subunit in perivenous cells from the ethanol-fed rats were significantly higher than from the perivenous control cells, whereas the total and surface expression of the beta1 integrin in periportal cells isolated from ethanol-fed and control rats were not significantly different.

CONCLUSIONS

The results indicated that in addition to impairing hepatocyte attachment, ethanol feeding also impairs another critical step of the adhesion process, that of hepatocyte spreading on extracellular matrix substrates. This defect occurred preferentially in perivenous cells and not periportal cells and was associated with an increase in beta1 integrin expression, suggesting that a compensatory mechanism occurs as an attempt by the perivenous cells to overcome impaired cell-matrix interactions caused by ethanol. Overall, these alterations in extracellular matrix-hepatocyte interactions could lead to alterations of hepatocyte structure and function and potentially play a role in alcoholic liver injury.

Selective lithiation of 2-methyloxazoles. Applications to pivotal bond constructions in the phorboxazole nucleus

[formula: see text] The lithiation of 2-methyloxazoles with alkyllithium and hindered lithium amide bases generally results in the competitive formation of a mixture of 5-lithio- and 2-(lithiomethyl)oxazole isomers. Herein a synthetically useful lithiation method which allows for the selective formation of 2-(lithiomethyl)oxazole is described. Diethylamine has been found to be a kinetically competent proton source that will mediate the equilibration of the kinetically formed 5-lithiooxazole to its more stable 2-(lithiomethyl)oxazole counterpart. Application of this metalation strategy with lithium diethylamide to two important bond constructions relevant to a projected phorboxazole synthesis is presented.

Development of a vertically integrated program of services for persons with schizophrenia

Economic pressures are changing the nature and quality of services available to individuals with chronic psychiatric disorders. Vertical integration of services has been proposed as a strategy for cost-effective merging of resources. This report describes the integration of inpatient, continuing day treatment, and ambulatory clinic services over an 18-month period into a service line for patients with schizophrenia. Key principles in implementing the integrated program included an open admission policy, continuity of care, use of criteria for level of care that were set by external review agencies, rapid transfers between services, and maintenance of the integrity of the treatment plan. Steps toward integration included evaluating and securing treatment resources, establishing core treatment approaches, fostering staff development, implementing outcomes assessment, and presenting the new program to clients, family members, and the community. The integrated program was 15 percent more productive than the combined services before integration, and inpatient length of stay dropped by 66 percent. Vertical integration of services is cost-effective and offers the potential for significant clinical benefits.

The relative influences of symptoms, insight, and neurocognition on social adjustment in schizophrenia and schizoaffective disorder

Impaired insight and neurocognitive deficits are commonly seen in schizophrenia. No study to date, however, has documented the relative influences of insight deficits, neurocognitive functioning, and psychotic symptoms on overall social adjustment in this population. This was done in a cohort of individuals recovering from acute exacerbations. Forty-six individuals with schizophrenia or schizoaffective disorder were recruited upon discharge from an inpatient unit. Symptom levels, neurocognitive functioning (information processing, memory, and executive functioning), and symptom awareness were documented, and social adjustment was assessed in three domains: treatment compliance, social behavior, and subjective quality of life. Cross-sectional data from initial assessments are reported. Sequential linear regression analyses identified differential associations between illness characteristics and outcome domains. Treatment compliance was most influenced by insight; social behavior deficits were associated with thought disorder and neurocognitive (working memory and visuo-spatial) impairments; and quality of life was associated with mood disturbances. Outcome is multidimensional in schizophrenia, and there are differential patterns of associations between illness characteristics and domains of social adjustment. Studies such as this can guide clinicians in determining the most appropriate treatments for specific individuals and should also guide researchers in efforts to clarify the processes that underlie treatment response and recovery in schizophrenia.

Close proximity of the heterosexual partner reduces the physiological and behavioral consequences of novel-cage housing in black tufted-ear marmosets (Callithrix kuhli)

The present studies assessed the extent to which heterosexual pairmates could buffer marmosets (Wied's black tufted-ear marmoset, Callithrix kuhli) against stress. Six male and six female marmosets from established groups were exposed to two experimental manipulations together with a control condition. Each condition lasted a total of 4 days. For the two experimental conditions, animals were removed from the family group and housed in a novel cage for 48 h in either the presence or the absence of the heterosexual pairmate. During the 48-h novel-cage housing period and for 48 h upon reunion of the subjects with the family group, concentrations of urinary cortisol were measured in the first void sample of the day and behavioral observations were conducted. When animals were housed alone in a novel cage they exhibited significant elevations in levels of urinary cortisol after 24 and 48 h of novel-cage exposure. In contrast, when marmosets were housed in the novel cage in the presence of the pairmate, levels of urinary cortisol did not change across the 4-day period. The presence of the social partner also reduced the behavioral manifestations of exposure to novelty. Upon reunion with the family group, animals that had been housed in the novel cage alone spent significantly more time in close proximity to the pairmate than animals that had been housed with the partner. A second experiment was conducted to determine the effect that separation from the pairmate, only (independent of any effects of novelty), had on levels of cortisol. Concentrations of urinary cortisol were measured in subjects housed in the familiar home cage, but in the absence of the pairmate, over a 48-h period and compared to concentrations of excreted cortisol immediately prior to separation. Separation from the pairmate did not elevate cortisol levels when the subject was housed in the home cage, suggesting that elevated cortisol levels in animals housed alone in the novel cage were in response to novelty exposure rather than to separation from the pairmate. Since the physical presence of the heterosexual partner reduced the physiological and behavioral effects of novel-cage housing, social attachments might function as homeostatic regulators of HPA function in marmosets.