Multilayer depressive symptom networks in adults with bodily pain living in precarious housing or homelessness

Housing insecurity is associated with co-occurring depression and pain interfering with daily activities. Network analysis of depressive symptoms along with associated risk or protective exposures may identify potential targets for intervention in patients with co-occurring bodily pain. In a community-based sample of adults (n = 408) living in precarious housing or homelessness in Vancouver, Canada, depressive symptoms were measured by the Beck Depression Inventory; bodily pain and impact were assessed with the 36-item Short Form Health Survey. Network and bootstrap permutation analyses were used to compare depressive symptoms endorsed by Low versus Moderate-to-Severe (Mod + Pain) groups. Multilayer networks estimated the effects of risk and protective factors. The overall sample was comprised of 78% men, mean age 40.7 years, with 53% opioid use disorder and 14% major depressive disorder. The Mod + Pain group was characterized by multiple types of pain, more persistent pain, more severe depressive symptoms and a higher rate of suicidal ideation. Global network connectivity did not differ between the two pain groups. Suicidal ideation was a network hub only in the Mod + Pain group, with high centrality and a direct association with exposure to lifetime trauma. Antidepressant medications had limited impact on suicidal ideation. Guilt and increased feelings of failure represented symptoms from two other communities of network nodes, and completed the shortest pathway from trauma exposure through suicidal ideation, to the non-prescribed opioid exposure node. Interventions targeting these risk factors and symptoms could affect the progression of depression among precariously housed patients.

Differential sensitivity of intraindividual variability dispersion and global cognition in the prediction of functional outcomes and mortality in precariously housed and homeless adults

OBJECTIVE

To examine cognitive intraindividual variability (IIV) dispersion as a predictor of everyday functioning and mortality in persons who are homeless or precariously housed.

METHOD

Participants were 407 community-dwelling adults, followed for up to 13 years. Neurocognition was assessed at baseline and IIV dispersion was derived using a battery of standardized tests. Functional outcomes (social, physical) were obtained at baseline and last follow-up. Mortality was confirmed with Coroner's reports and hospital records (N  = 103 deaths). Linear regressions were used to predict current social and physical functioning from IIV dispersion. Repeated measures Analysis of Covariance were used to predict long-term change in functioning. Cox regression models examined the relation between IIV dispersion and mortality. Covariates included global cognition (i.e. mean-level performance), age, education, and physical comorbidities.

RESULTS

Higher IIV dispersion predicted poorer current physical functioning (B = -0.46 p = .010), while higher global cognition predicted better current (B  = 0.21, p = .015) and change in social functioning over a period of up to 13 years (F  = 4.23, p = .040). Global cognition, but not IIV dispersion, predicted mortality in individuals under 55 years old (HR = 0.50, p = .013).

CONCLUSIONS

Our findings suggest that indices of neurocognitive functioning (i.e. IIV dispersion and global cognition) may be differentially related to discrete dimensions of functional outcomes in an at-risk population. IIV dispersion may be a complimentary marker of emergent physical health dysfunction in precariously housed adults and may be best used in conjunction with traditional neuropsychological indices.

Relationship between drug-induced movement disorders and psychosis in adults living in precarious housing or homelessness

BACKGROUND

Studies have reported positive associations between drug-induced movement disorders (DIMDs) and symptoms of psychosis in patients with schizophrenia. However, it is not clear which subtypes of symptoms are related to each other, and whether one symptom precedes another. The current report assessed both concurrent and temporal associations between DIMDs and symptoms of psychosis in a community-based sample of homeless individuals.

METHODS

Participants were recruited in Vancouver, Canada. Severity of DIMDs and psychosis was rated annually, allowing for the analysis of concurrent associations between DIMDs and Positive and Negative Syndrome Scale (PANSS) five factors. A brief version of the PANSS was rated monthly using five psychotic symptoms, allowing for the analysis of their temporal associations with DIMDs. Mixed-effects linear and logistic regression models were used to assess the associations.

RESULTS

401 participants were included, mean age of 40.7 years (SD = 11.2) and 77.4% male. DIMDs and symptoms of psychosis were differentially associated with each other, in which the presence of parkinsonism was associated with greater negative symptoms, dyskinesia with disorganized symptoms, and akathisia with excited symptoms. The presence of DIMDs of any type was not associated with depressive symptoms. Regarding temporal associations, preceding delusions and unusual thought content were associated with parkinsonism, whereas dyskinesia was associated with subsequent conceptual disorganization.

CONCLUSIONS

The current study found significant associations between DIMDs and symptoms of psychosis in individuals living in precarious housing or homelessness. Moreover, there were temporal associations between parkinsonism and psychotic symptoms (delusions or unusual thought content), and the presence of dyskinesia was temporally associated with higher odds of clinically relevant conceptual disorganization.

Using serial position effects to investigate memory dysfunction in homeless and precariously housed persons

Background: Homeless and precariously housed persons exhibit significant memory impairment, but the component processes underlying memory dysfunction have not been explored. We examined the serial position profile (i.e., primacy and recency effects) of verbal memory and its neuroanatomical correlates to identify the nature of memory difficulties in a large cohort of homeless and precariously housed adults. Method: The sample included 227 community-dwelling homeless and precariously housed adults. Serial position scores (primacy, middle, recency) were computed using the Hopkins Verbal Learning Test-Revised. Paired sample t-tests were used to compare percent recall from each word list region. Age-adjusted correlations assessed associations between serial position scores and other cognitive domains (attention, processing speed, executive functioning). Regression analyses were conducted to examine regional brain volumes of interest (hippocampus, entorhinal cortex, dorsolateral prefrontal cortex [DLPFC]) and their differential associations with serial position scores. Results: The serial position profile was characterized by a diminished recency effect in relation to the primacy effect. Serial position scores positively correlated with sustained attention and cognitive control. Larger hippocampal volume was associated with better primacy item recall. DLPFC volume was not associated with serial position recall after adjustment for false discovery rate. There were no associations between regional brain volumes and recency item recall. Conclusion: Our results suggest that commonly reported memory difficulties in homeless and precariously housed adults are likely secondary to a core deficit in executive control due to compromised frontal lobe functioning. These findings have implications for cognitive rehabilitation in this complex and vulnerable group.

Social Networks, Stigma, and Hepatitis C Care Among Women Who Inject Drugs: Findings from A Community Recruited Sample

This study explores the role of perceived HCV stigma and social networks on HCV care among people who inject drugs (PWID) of both sexes, and solely among women who inject drugs (WWID). Data were from 269 HCV positive PWID, community-recruited through street-based outreach in Baltimore, MD. We defined HCV stigma based on participants' perceptions of treatment by others and their need to conceal their HCV status. Among WWID, HCV stigma was linked with decreased odds of undergoing liver disease staging (aOR = 0.33, 95% CI: 0.13,0.85) or to have attempted to get the HCV cure (aOR = 0.39, CI: 0.16,0.97), these associations were not evident in the overall sample with both sexes. Social network characteristics were significant correlates of HCV care in the overall sample, and these associations were stronger among WWID. WWID with more HCV positive social network members had higher odds of an HCV-related healthcare visit in the prior 12 months (aOR = 4.28, CI: 1.29,14.17) and to have undergone liver disease staging (aOR = 2.85, CI: 1.01,8.05). WWID with more social network members aware of the HCV cure were more likely to report an attempt at obtaining the HCV cure (aOR = 5.25, CI: 1.85,14.89). Our results suggest complexity in the role of social networks and stigma on HCV care.

Rasch analysis of the beck depression inventory in a homeless and precariously housed sample

The approach to analysis of and interpretation of findings from the Beck Depression Inventory (BDI), a self-report questionnaire, depends on sample characteristics. To extend work using conventional BDI scoring, the BDI's suitability in assessing symptom severity in a homeless and precariously housed sample was examined using Rasch analysis. Participants (n=478) recruited from an impoverished neighbourhood in Vancouver, Canada, completed the BDI. Rasch analysis using the partial credit model was done, and the structural validity, unidimensionality, and reliability of the BDI were studied. A receiver operating characteristic curve determined a Rasch cut-off score consistent with clinical depression, and Rasch scores were correlated with raw scores. Good fit to the Rasch model was observed after rescoring all items and removing Item 19 (Weight Loss), and unidimensionality and reliability were satisfactory. Item 9 (Suicidal Wishes) represented the most severe symptom. Rasch-based scores detected clinical depression with moderate sensitivity and specificity, and were positively correlated with conventional scores. The BDI in a community-based sample of homeless and precariously housed adults satisfied Rasch model expectations in a 20-item format, and is suitable for assessing symptom severity. Future research on depression in similar samples may reveal more information on using specific symptoms to determine clinical significance.

Opioid and stimulant attributed treatment admissions and fatal overdoses: Using national surveillance data to examine the intersection of race, sex, and polysubstance use, 1992-2020

BACKGROUND

We use national surveillance data to evaluate race/ethnicity by sex/gender differences and trends in substance use treatment admissions and overdose deaths involving opioid and stimulant use.

METHODS

We used data (1992-2019) from the Treatment Episode Dataset-Admissions to identify treatment admissions and the Center for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research (1999-2020) to identify overdose deaths. We assessed treatment admissions and related drug overdose deaths per 100,000 adults by sex and race/ethnicity for opioid and stimulant groups: cocaine, opioid, methamphetamines, cocaine and opioid use, cocaine and methamphetamines, and opioid and methamphetamines.

RESULTS

We found significant variations in treatment admissions and deaths by race/ethnicity and sex/gender. Cocaine-related treatment admissions and deaths were most prevalent among Non-Hispanic Black individuals over the study years, yet lower rates were evident among individuals from other racial/ethnic groups. Notably, Non-Hispanic Black men experienced larger increases in cocaine-only admissions than men of other racial/ethnic groups between 1992 and 2019. Men had higher opioid and stimulant treatment admissions and overdose deaths than women. We observed skyrocketing methamphetamine deaths among American Indian/Native Alaskan men and women from 1992 to 2019.

DISCUSSION

Steep increases in overdose deaths fueled by methamphetamines among Non-Hispanic Native Americans and cocaine among Non-Hispanic Black individuals suggest a need for more effective interventions to curb stimulant use. Variations by race/ethnicity and sex/gender also suggest interventions should be developed through an intersectionality lens.

Movement disorders associated with substance use in adults living in precarious housing or homelessness

OBJECTIVE

Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proportion affected and severity of different signs of MDs, as well as their associations with substance use in a community-based sample of precariously housed and homeless individuals.

METHODS

Participants were recruited from an impoverished urban neighborhood and were assessed for substance dependence and self-reported substance use (alcohol, cannabis, cocaine, methamphetamine, nicotine, and opioids), as well as for the severity of signs of MDs (akathisia, dyskinesia, dystonia, and parkinsonism). Adjusted regression models were used to estimate the associations of the severity of signs with the frequency of substance use over the past 4 weeks and with the baseline diagnosis of substance dependence.

RESULTS

The proportion of the sample with clinically relevant signs of MDs in any of the four categories was 18.6% (n = 401), and these participants demonstrated lower levels of functioning than those without signs. Of the different types of substance use, only methamphetamine (its frequency of use and dependence) was significantly associated with greater severity of overall signs of MDs. Frequency of methamphetamine use significantly interacted with age and sex, whereby older female participants exhibited the greatest overall severity with increased methamphetamine use. Of the different signs of MDs, methamphetamine use frequency was positively associated with the severity of trunk/limb dyskinesia and hypokinetic parkinsonism. Relative to no use, concurrent use of antipsychotics demonstrated lower severity of trunk/limb dyskinesia and greater severity of hypokinetic parkinsonism with methamphetamine use, and greater severity of dystonia with cocaine use.

CONCLUSIONS

Our study found a high proportion of MDs in a relatively young sample, and their severity was consistently associated with methamphetamine use, moderated by participant demographics and antipsychotic use. These disabling sequelae represent an important and understudied neurological condition that may affect quality of life and will require further study.

Reduction in Substance-Related Composite Harm Scores Through Street Soccer

Introduction Street soccer makes the sport accessible to people affected by homelessness or precarious housing. There is overwhelming evidence that exercise improves physical and mental health. In addition, sport facilitates positive peer pressure that leads to beneficial life changes. Method To examine participants' accounts of the effects of street soccer in a sample of socially disadvantaged players from Western Canada, we collected 73 cross-sectional self-reports of life changes via a questionnaire. The questionnaire included questions on social, mental, and physical health, including substance use. This allowed the calculation of a modified composite harm score. Results Participants reported improved physical (46% of participants) and mental (43% of participants) health, reduced cigarette (50% of smokers), alcohol (45% of users), cannabis (42% of users), and other non-prescribed drug use, increased number of friends (88% of participants), improved housing (60% of participants), increased income (19% of participants), increased community medical supports (40% of participants), and decreased conflicts with police (47% of those with prior recent conflict). Perceived reductions in substance use were supported by significant changes in composite harm score. Conclusion Street soccer appears to promote improved physical, mental, and social health among people affected by homelessness or precarious housing, with reduction in substance use likely to be a key factor. This work builds upon past qualitative research showing the benefits of street soccer and supports future research which may help elucidate the mechanisms by which street soccer has beneficial effects.

Daily opioid and stimulant co-use and nonfatal overdoses in the context of social disadvantage: Findings on marginalized populations

OBJECTIVE

Opioids and stimulants are increasingly implicated in overdose deaths, particularly among minoritized groups. We examined daily opioid and cocaine co-use, nonfatal overdoses, and naloxone carrying among minoritized people who inject drugs (PWID).

METHODS

The study derived data from 499 PWID in Baltimore City, MD, recruited using street-based outreach between 2016 and 2019. Participants reported overdoses; sociodemographic characteristics; and use of nonmedical prescription opioids, heroin, cocaine, and naloxone.

RESULTS

Among the participants, the mean age was 46, 34 % were female, 64 % self-identified as Black, and 53 % experienced recent homelessness. Black PWID, compared to White PWID, were as likely to use opioids and cocaine daily but were 61 % less likely to have naloxone. After controlling for sociodemographic characteristics, women (aOR:1.88, 95%CI: 1.14, 3.11), persons experiencing homelessness (aOR:3.07, 95%CI: 1.79, 5.24), and those who experienced a recent overdose (aOR:2.14, 95%CI: 1.29, 3.58) were significantly more likely to use opioids and any form of cocaine every day. In a subanalysis of only female PWID, females engaged in sex work (aOR:2.27, 95%CI: 1.02, 5.07) and females experiencing recent homelessness (aOR:5.82, 95%CI: 2.50, 13.52) were significantly more likely to use opioids and cocaine daily. Furthermore, females (aOR:1.69, 95%CI:1.03, 2.77), persons experiencing homelessness (aOR:1.94, 95%CI:1.16, 3.24), and those with higher educational attainment (aOR:2.06, 95%CI:1.09, 3.91) were more likely to often/always carry naloxone, while Black PWID were less likely to have naloxone (aOR:0.39, 95%CI:0.22, 0.69).

CONCLUSIONS

These findings highlight the need for targeted naloxone distribution and other harm-reduction interventions among minoritized groups in urban areas.

Differential age-associated brain atrophy and white matter changes among homeless and precariously housed individuals compared with the general population

Background

Homeless or precariously housed individuals live with poor health and experience premature mortality compared with the general population, yet little is known about age-related brain changes among these individuals. We evaluated whether MRI measures of brain structure are differentially associated with age and selected risk factors among individuals who are homeless or precariously housed compared with a general population sample.

Methods

We compared T1-weighted and diffusion tensor imaging measures of brain macrostructure and white matter microstructure in a well-characterised sample of 312 precariously housed participants with a publicly available dataset of 382 participants recruited from the general population. We used piecewise and multiple linear regression to examine differential associations between MRI measures and between the samples, and to explore associations with risk factors in the precariously housed sample.

Results

Compared with the general population sample, older age in the precariously housed sample was associated with more whole-brain atrophy (β=-0.20, p=0.0029), lower whole-brain fractional anisotropy (β=-0.32, p<0.0001) and higher whole-brain mean diffusivity (β=0.69, p<0.0001). Several MRI measures had non-linear associations with age, with further adverse changes after age 35-40 in the precariously housed sample. History of traumatic brain injury, stimulant dependence and heroin dependence was associated with more atrophy or alterations in white matter diffusivity in the precariously housed sample.

Conclusions

Older age is associated with adverse MRI measures of brain structure among homeless and precariously housed individuals compared with the general population. Education, improvements in care provision and policy may help to reduce the health disparities experienced by these individuals.

Dynamic networks of psychotic symptoms in adults living in precarious housing or homelessness

BACKGROUND

People living in precarious housing or homelessness have higher than expected rates of psychotic disorders, persistent psychotic symptoms, and premature mortality. Psychotic symptoms can be modeled as a complex dynamic system, allowing assessment of roles for risk factors in symptom development, persistence, and contribution to premature mortality.

METHOD

The severity of delusions, conceptual disorganization, hallucinations, suspiciousness, and unusual thought content was rated monthly over 5 years in a community sample of precariously housed/homeless adults (n = 375) in Vancouver, Canada. Multilevel vector auto-regression analysis was used to construct temporal, contemporaneous, and between-person symptom networks. Network measures were compared between participants with (n = 219) or without (n = 156) history of psychotic disorder using bootstrap and permutation analyses. Relationships between network connectivity and risk factors including homelessness, trauma, and substance dependence were estimated by multiple linear regression. The contribution of network measures to premature mortality was estimated by Cox proportional hazard models.

RESULTS

Delusions and unusual thought content were central symptoms in the multilevel network. Each psychotic symptom was positively reinforcing over time, an effect most pronounced in participants with a history of psychotic disorder. Global connectivity was similar between those with and without such a history. Greater connectivity between symptoms was associated with methamphetamine dependence and past trauma exposure. Auto-regressive connectivity was associated with premature mortality in participants under age 55.

CONCLUSIONS

Past and current experiences contribute to the severity and dynamic relationships between psychotic symptoms. Interrupting the self-perpetuating severity of psychotic symptoms in a vulnerable group of people could contribute to reducing premature mortality.

Delayed Opsoclonus-Myoclonus Syndrome After Ovarian Teratoma Resection

ABSTRACT

Opsoclonus-myoclonus syndrome (OMS) is a rare syndrome characterized by opsoclonus, which is irregular, spontaneous, multivectorial saccadic eye movements, along with diffuse or focal myoclonus and sometimes ataxia. OMS is associated with paraneoplastic etiologies in 20%-40% of cases, with small-cell lung and breast cancers the most common associated primary neoplasms in adults, whereas neuroblastoma is more common in children and ovarian teratoma may occur in women younger than 30 years. Onconeural antibodies are often not identified. In existing literature, paraneoplastic OMS precedes identification of the neoplasm, and neurological recovery depends on treatment of the underlying cancer. We describe a 27-year-old woman with the delayed onset of OMS one month after resection of ovarian teratoma, likely due to immune trigger from antigen exposure at the time of resection. She was treated with intravenous methylprednisolone, immunoglobulins, and eventually rituximab with resolution of her symptoms. Identification of OMS after tumor resection and prompt immunotherapy are critical for neurologic recovery. At 30-month follow-up, this patient had not experienced recurrence of OMS.

Racial differences in overdose training, naloxone possession, and naloxone administration among clients and nonclients of a syringe services program

OBJECTIVE

To evaluate racial (Black/White) differences in overdose response training and take-home naloxone (THN) possession and administration among clients and nonclients of the Baltimore syringe service program (SSP).

METHODS

The study derived data from a cross-sectional survey of 263 (183 SSP clients, 80 nonclients) people who inject drugs (PWID). The study recruited SSP clients using targeted sampling and recruited nonclients through peer referral from April to November 2016.

RESULTS

In our sample, 61% of the participants were Black, 42% were between the ages of 18 and 44, and 70% were males. SSP clients, regardless of race, were more likely to have received overdose response training than Black nonclients (Black clients AOR: 3.85, 95% CI: 1.88, 7.92; White clients AOR: 2.73, 95% CI: 1.29, 5.75). The study found no significant differences in overdose response training between Black and White nonclients. SSP clients and White nonclients were more likely to possess THN than Black nonclients (Black clients: AOR: 4.21, 95% CI: 2.00, 8.87; White clients: AOR: 3.54, 95% CI: 1.56, 8.04; White nonclients AOR: 4.49, 95% CI: 1.50,13.47).

CONCLUSION

SSP clients were more likely to receive overdose response training than their nonclient peers who they referred to the study, illustrating the utility of SSPs in reaching PWID at high risk of overdose. We also observed that Black PWID, who did not access services at the SSP, were the least likely to possess THN, suggesting the need to employ outreach targeting Black PWID who do not access this central harm reduction intervention.

Component Processes of Decision Making in a Community Sample of Precariously Housed Persons: Associations With Learning and Memory, and Health-Risk Behaviors

The Iowa Gambling Task (IGT) is a widely used measure of decision making, but its value in signifying behaviors associated with adverse, "real-world" consequences has not been consistently demonstrated in persons who are precariously housed or homeless. Studies evaluating the ecological validity of the IGT have primarily relied on traditional IGT scores. However, computational modeling derives underlying component processes of the IGT, which capture specific facets of decision making that may be more closely related to engagement in behaviors associated with negative consequences. This study employed the Prospect Valence Learning (PVL) model to decompose IGT performance into component processes in 294 precariously housed community residents with substance use disorders. Results revealed a predominant focus on gains and a lack of sensitivity to losses in these vulnerable community residents. Hypothesized associations were not detected between component processes and self-reported health-risk behaviors. These findings provide insight into the processes underlying decision making in a vulnerable substance-using population and highlight the challenge of linking specific decision making processes to "real-world" behaviors.

Differential effects of cannabis exposure during early versus later adolescence on the expression of psychosis in homeless and precariously housed adults

Longitudinal studies of cannabis exposure during early adolescence in the general population frequently report an increased risk of subsequently developing psychotic symptoms or a psychotic illness. However, there is a dearth of knowledge about the effects of early cannabis exposure on psychosis in homeless and precariously housed adults, who represent a population afflicted with high rates of psychosis. The aim of the present study was to examine how early cannabis exposure (by age 15) compared to later first use (after age 15) affected the expression of adult psychosis in this population. Secondary measures of psychopathology, drug use, cognition and brain structure were also collected. 437 subjects were recruited from single room occupancy hotels in the urban setting of the Downtown Eastside of Vancouver, Canada. Psychiatric diagnoses were determined, and psychotic symptom severity was measured with the 5-factor PANSS. Participants completed a battery of neurocognitive tests, and brain structure was assessed using structural and diffusion tensor imaging MRI scans. Results indicated that early cannabis exposure was associated with an increased risk (OR = 1.09, p < .05) of developing substance induced psychosis, whereas later first use increased risk (OR = 2.19, p < .01) of developing schizophrenia or schizoaffective disorder. There was no group difference in neurocognitive function, although differences were observed in the lateral orbitofrontal cortex and white matter tract diffusivity. These findings indicate that early cannabis exposure in this population may increase the risk of developing drug associated psychoses, which could potentially be mediated in part through altered neurodevelopmental brain changes.

Characterization of Bodily Pain and Use of Both Prescription and Non-Prescription Opioids in Tenants of Precarious Housing

opioid use, which includes both prescribed and non-prescribed drugs, is relatively common amongst marginalized populations. Past research has shown that among those who use non-prescribed or diverted opioids recreationally, many were first exposed to the drug as prescribed pain medication. Objective: to better understand the relationship between pain and opioid use in tenants of precarious housing. Methods: in the present study, 440 individuals from a cohort living in homeless or precariously housed conditions in a neighborhood with high rates of poverty and drug use were interviewed for their bodily pain and opioid use. We examined the relationship between bodily pain levels, assessed using the Maudsley Addiction Profile questionnaire, and prescribed, non-prescribed and combined self-reported opioid use in the prior 28 days assessed using the Timeline Followback and Doctor-Prescribed Medication Timeline Followback questionnaires. Results: Analysis of the results indicated that sex (female), age (younger) and early exposure to opioids (≤ age 18) predicted current opioid use, but there was no association between current bodily pain levels and opioid use. Conclusions: these unexpected findings indicate the complex nature of the relationship between pain and opioid use in this population.

Cerebral Small Vessel Disease, Risk Factors, and Cognition in Tenants of Precarious Housing

BACKGROUND AND PURPOSE

We aim to describe the burden, characteristics, and cognitive associations of cerebral small vessel disease in a Canadian sample living with multimorbidity in precarious housing.

METHODS

Participants received T1, T2-fluid-attenuated inversion recovery, and susceptibility-weighted imaging 3T magnetic resonance imaging sequences and comprehensive clinical, laboratory, and cognitive assessments. Cerebral small vessel disease burden was characterized using a modified Small Vessel Disease (mSVD) score. One point each was given for moderate-severe white matter hyperintensities, ≥1 cerebral microbleeds, and ≥1 lacune. Multivariable regression explored associations between mSVD score, risk factors, and cognitive performance.

RESULTS

Median age of the 228 participants (77% male) was 44.7 years (range, 23.3-63.2). In n=188 participants with consistent good quality magnetic resonance imaging sequences, mSVD scores were 0 (n=127, 68%), 1 (n=50, 27%), and 2 (n=11, 6%). Overall, one-third had an mSVD ≥1 n=61 (32%); this proportion was unchanged when adding participants with missing sequences n=72/228 (32%). The most prevalent feature was white matter hyperintensities 53/218 (24%) then cerebral microbleed 16/191 (8%) and lacunes 16/228 (7%). Older age (odds ratio, 1.10 [95% CI, 1.05-1.15], P<0.001), higher diastolic blood pressure (odds ratio, 1.05 [95% CI, 1.01-1.09], P=0.008), and a history of injection drug use (odds ratio, 3.13 [95% CI, 1.07-9.16], P=0.037) had significant independent associations with a mSVD score of ≥1 in multivariable analysis. mSVD ≥1 was associated with lower performance on tests of verbal memory, sustained attention, and decision-making, contributing 4% to 5% of the variance in each cognitive domain.

CONCLUSIONS

The 32% prevalence of cerebral small vessel disease in this young, socially marginalized cohort was higher than expected for age and was associated with poorer cognitive performance.

Amygdala Nuclei Volumes Are Selectively Associated With Social Network Size in Homeless and Precariously Housed Persons

Objective: The amygdala is a brain region comprised of a group of functionally distinct nuclei that play a central role in social behavior. In homeless and precariously housed individuals, high rates of multimorbidity, and structural aspects of the environment may dysregulate social functioning. This study examined the neurobiological substrates of social connection in homeless and precariously housed persons by examining associations between amygdala nuclei volumes and social network size. Methods: Sixty participants (mean age 43.6 years; 73.3% male) were enrolled from an ongoing study of homeless and precariously housed adults in Vancouver, Canada. Social network size was assessed using the Arizona Social Support Interview Schedule. Amygdala nuclei volumes were extracted from anatomic T1-weighted MRI data. The central and basolateral amygdala nuclei were selected as they are implicated in anxiety-related and social behaviors. The hippocampus was included as a control brain region. Multivariable regression analysis investigated the relationship between amygdala nuclei volumes and social network size. Results: After controlling for age, sex, and total brain volume, individuals with the larger amygdala and central nucleus volumes had a larger network size. This association was not observed for the basolateral amygdala complex, though subsequent analysis found the basal and accessory basal nuclei of the basolateral amygdala were significantly associated with social network size. No association was found for the lateral amygdala nucleus or hippocampus. Conclusions: These findings suggest that select amygdala nuclei may be differentially involved in the social connections of persons with multimorbid illness and social marginalization.

Cognitive decline and mortality in a community-based sample of homeless and precariously housed adults: 9-year prospective study

BACKGROUND

Homeless and precariously housed individuals experience a high burden of comorbid illnesses, and excess mortality. Cross-sectional studies report a high rate of cognitive impairment. Long-term trajectories have not been well investigated in this group.

AIMS

To longitudinally assess risks for premature and/or accelerated cognitive ageing, and the relationship with early mortality in homeless and precariously housed people.

METHOD

This is a 9-year community-based study of 375 homeless and precariously housed individuals from Vancouver, Canada. Annual cognitive testing assessed verbal learning and memory, and inhibitory control. Linear mixed-effects models examined associations between clinical risk factors (traumatic brain injury, psychotic disorders, viral exposure, alcohol dependence) and cognitive change over 9 years. Cox regression models examined the association between cognition and mortality.

RESULTS

Traumatic brain injury and alcohol dependence were associated with decline in verbal memory. Inhibitory control declined, independent of risk factors and to a greater extent in those who died during the study. Better inhibitory control was associated with a 6.6% lower risk of mortality at study entry, with a 0.3% greater effect for each year of life. For each one-point increase in the Charlson Comorbidity Index score at study entry, the risk of mortality was 9.9% higher, and was consistent across age. Adjusting for comorbidities, inhibitory control remained a significant predictor of mortality.

CONCLUSIONS

Findings raise the possibility of a premature onset, and accelerated trajectory, of cognitive ageing in this group of homeless and precariously housed people. Traumatic brain injury, alcohol dependence and cognition could be treatment priorities.

Comparing Canadian and United States opioid agonist therapy policies

Canada and the United States (U.S.) face an opioid use disorder (OUD) and opioid overdose epidemic. The most effective OUD treatment is opioid agonist therapy (OAT)-buprenorphine (with and without naloxone) and methadone. Although federal approval for OAT occurred decades ago, in both countries, access to and use of OAT is low. Restrictive policies and complex regulations contribute to limited OAT access. Through a non-systematic literature scan and a review of publicly available policy documents, we examined and compared OAT policies and practice at the federal (Canada vs. U.S.) and local levels (British Columbia [B.C.] vs. Oregon). Differences and similarities were noted between federal and local OAT policies, and subsequently OAT access. In Canada, OAT policy control has shifted from federal to provincial authorities. Conversely, in the U.S., federal authorities maintain primary control of OAT regulations. Local OAT health insurance coverage policies were substantively different between B.C. and Oregon. In B.C., five OAT options were available, while in Oregon, only two OAT options were available with administrative limitations. The differences in local OAT access and coverage policies between B.C. and Oregon, may be explained, in part, to the differences in Canadian and U.S. federal OAT policies, specifically, the relaxation of special federal OAT regulatory controls in Canada. The analysis also highlights the complicating contributions, and likely policy solutions, that exist within other drug policy sub-domains (e.g., the prescription regime, and drug control regime) and broader policy domains (e.g., constitutional rights). U.S. policymakers and health officials could consider adopting Canada's regulatory policy approach to expand OAT access to mitigate the harms of the ongoing opioid overdose epidemic.

Cognitive Impairment in Marginally Housed Youth: Prevalence and Risk Factors

Objective: Homeless and marginally housed youth are particularly vulnerable members of society, and are known to experience numerous health problems, including psychiatric illness, substance use, and viral infection. Despite the presence of these risk factors for cognitive compromise, there is limited research on the cognitive functioning of homeless and marginally housed youth. The present study examines the degree and pattern of cognitive impairment and associations with key risk factors in a sample of marginally housed young adults.

Method: Participants (N = 101) aged 20–29 years old were recruited from single-room occupancy hotels, and underwent cognitive, psychiatric, neurological, and serological assessments.

Results: Forty percent of participants were identified as mildly cognitively impaired across multiple domains, and 16% were moderately-severely impaired. Deficits in memory and attention were most prevalent, while impairments in inhibitory control/processing speed and cognitive flexibility were also present but tended to be less severe. Developmental and historical factors (premorbid intellectual functioning, neurological soft signs, earlier exposure to and longer duration of homelessness or marginal housing), as well as current health risks (stimulant dependence and hepatitis C exposure), were associated with cognitive impairment.

Conclusions: The strikingly high rate of cognitive impairment in marginally housed young adults represents a major public health concern and is likely to pose a significant barrier to treatment and rehabilitation. These results suggest that the pathway to cognitive impairment involves both developmental vulnerability and modifiable risk factors. This study highlights the need for early interventions that address cognitive impairment and risk factors in marginalized young people.

Social and structural factors associated with substance use within the support network of adults living in precarious housing in a socially marginalized neighborhood of Vancouver, Canada

BACKGROUND

The structure of a social network as well as peer behaviours are thought to affect personal substance use. Where substance use may create health risks, understanding the contribution of social networks to substance use may be valuable for the design and implementation of harm reduction or other interventions. We examined the social support network of people living in precarious housing in a socially marginalized neighborhood of Vancouver, and analysed associations between social network structure, personal substance use, and supporters' substance use.

METHODS

An ongoing, longitudinal study recruited 246 participants from four single room occupancy hotels, with 201 providing social network information aligned with a 6-month observation period. Use of tobacco, alcohol, cannabis, cocaine (crack and powder), methamphetamine, and heroin was recorded at monthly visits. Ego- and graph-level measures were calculated; the dispersion and prevalence of substances in the network was described. Logistic mixed effects models were used to estimate the association between ego substance use and peer substance use. Permutation analysis was done to test for randomness of substance use dispersion on the social network.

RESULTS

The network topology corresponded to residence (Hotel) with two clusters differing in demographic characteristics (Cluster 1 -Hotel A: 94% of members, Cluster 2 -Hotel B: 95% of members). Dispersion of substance use across the network demonstrated differences according to network topology and specific substance. Methamphetamine use (overall 12%) was almost entirely limited to Cluster 1, and absent from Cluster 2. Different patterns were observed for other substances. Overall, ego substance use did not differ over the six-month period of observation. Ego heroin, cannabis, or crack cocaine use was associated with alter use of the same substances. Ego methamphetamine, powder cocaine, or alcohol use was not associated with alter use, with the exception for methamphetamine in a densely using part of the network. For alters using multiple substances, cannabis use was associated with lower ego heroin use, and lower ego crack cocaine use. Permutation analysis also provided evidence that dispersion of substance use, and the association between ego and alter use was not random for all substances.

CONCLUSIONS

In a socially marginalized neighborhood, social network topology was strongly influenced by residence, and in turn was associated with type(s) of substance use. Associations between personal use and supporter's use of a substance differed across substances. These complex associations may merit consideration in the design of interventions to reduce risk and harms associated with substance use in people living in precarious housing.

Volumes of the Hippocampal Formation Differentiate Component Processes of Memory in a Community Sample of Homeless and Marginally Housed Persons

OBJECTIVE

Persons who are homeless or marginally housed exhibit significant cognitive dysfunction, with memory being the most impaired domain. Hippocampal subfield volumes have been found to differentially relate to component processes of memory. The neural correlates of memory have not been previously examined in marginalized persons who are understudied and underserved. We examined whether hippocampal subfields and entorhinal cortex volumes are uniquely related to indices of verbal episodic memory using the Hopkins Verbal Learning Test - Revised.

METHOD

Data was used from a large sample of community dwelling homeless and marginally housed adults (N = 227). Regression analyses were conducted to examine hippocampal subfield volumes (CA1, CA3, CA4, dentate gyrus, subiculum) and entorhinal cortex, and their associations with measures of verbal immediate recall, learning slope, and verbal delayed recall.

RESULTS

Greater CA3 subfield volume was associated with better performance on an index of encoding (immediate recall), but only in older individuals. Greater CA1 and subiculum volumes were associated with better performance on immediate and delayed recall (measures that tap into retrieval processes), but not with learning slope (a more pure index of encoding). Entorhinal cortex volume was related to all components of memory beyond total hippocampal volume.

CONCLUSIONS

Our results suggest common neuroanatomical correlates of memory dysfunction in large sample of marginalized persons, and these are uniquely related to different components of memory. These findings have clinical relevance for marginalized populations and theoretical relevance to the growing literature on functional specialization of the hippocampal subfields.

Prevalence and Risk Factors of Brain Infarcts and Associations With Cognitive Performance in Tenants of Marginal Housing

Background

Homeless and vulnerably housed individuals are at increased risk for multimorbidity compared with the general population. We assessed prevalence of brain infarcts on neuroimaging and associations with vascular risk factors and cognitive performance in a prospective study of residents living in marginal housing.

Methods and Results

Two hundred twenty‐eight participants underwent structured clinical interviews, targeted clinical, laboratory, and neuropsychological assessments, and magnetic resonance imaging with T₁, T₂‐fluid‐attenuated inversion recovery and susceptibility‐weighted images. Subjects underwent cognitive testing to assess premorbid IQ, verbal learning and memory, inhibition, sustained attention, mental flexibility, and decision making. In this sample (mean age 44.0 years [SD 9.4], 77% male), prevalence of conventional vascular risk factors was lower than in the general population apart from tobacco use (94%). Ten‐year Framingham risk for any cardiovascular event was 11.4%±9.2%. Brain infarcts were present in 25/228 (11%). All were ischemic (40% cortical, 56% lacunar, 4% both). Participants with infarcts were older than those without (48.9±9.4 versus 43.4±9.2, P=0.006). In a multivariable regression analysis, only age remained a significant predictor of brain infarcts (odds ratio 1.08, 95% CI1.02–1.14, P=0.004). After controlling for age and education, the presence of infarct was a significant predictor of impaired decision making on the Iowa Gambling Task of decision making (β −28.2, 95% CI −42.7 to −14.1, P<0.001).

Conclusions

Prevalence of infarcts on neuroimaging in this disadvantaged, community‐dwelling cohort was much higher than expected for age and was associated with impaired decision making. Further research is needed to identify individuals at highest risk who may benefit from targeted preventative strategies.

Cognitive profiles and associated structural brain networks in a multimorbid sample of marginalized adults

Introduction

Cognition is impaired in homeless and vulnerably housed persons. Within this heterogeneous and multimorbid group, distinct profiles of cognitive dysfunction are evident. However, little is known about the underlying neurobiological substrates. Imaging structural covariance networks provides a novel investigative strategy to characterizing relationships between brain structure and function within these different cognitive subgroups.

Method

Participants were 208 homeless and vulnerably housed persons. Cluster analysis was used to group individuals on the basis of similarities in cognitive functioning in the areas of attention, memory, and executive functioning. The principles of graph theory were applied to construct two brain networks for each cognitive group, using measures of cortical thickness and gyrification. Global and regional network properties were compared across networks for each of the three cognitive clusters.

Results

Three cognitive groups were defined by: higher cognitive functioning across domains (Cluster 1); lower cognitive functioning with a decision-making strength (Cluster 3); and an intermediate group with a relative executive functioning weakness (Cluster 2). Between-group differences were observed for cortical thickness, but not gyrification networks. The lower functioning cognitive group exhibited higher segregation and reduced integration, higher centrality in select nodes, and less spatially compact modules compared with the two other groups.

Conclusions

The cortical thickness network differences of Cluster 3 suggest that major disruptions in structural connectivity underlie cognitive dysfunction in a subgroup of people who have a high multimorbid illness burden and who are vulnerably housed or homeless. The origins, and possible plasticity of these structure-function relationships identified with network analysis warrant further study.

The Integration of Clinical and Research Training: How and Why MD-PhD Programs Work

For over 60 years, MD-PhD programs have provided integrated clinical and research training to produce graduates primed for physician-scientist careers. Yet the nature of this integrated training is poorly characterized, with no program theory of MD-PhD training to guide program development or evaluation. The authors address this gap by proposing a program theory of integrated MD-PhD training applying constructs from cognitive psychology and medical education. The authors argue that integrated physician-scientist training requires development of at least three elements in trainees: cognitive synergy, sense of self, and professional capacity. First, integrated programs need to foster the cognitive ability to synergize and transfer knowledge between the clinical and research realms. Second, integrated programs need to facilitate development of a unique and emergent identity as a physician-scientist that is more than the sum of the individual roles of physician and scientist. Third, integrated programs should develop core competencies unique to physician-scientists in addition to those required of each independently. The authors describe how programs can promote development of these elements in trainees, summarized in a logic model. Activities and process measures are provided to assist institutions in enhancing integration. Specifically, programs can enact the proposed theory by providing tailored MD-PhD curricula, personal development planning, and a supportive community of practice. It is high time to establish a theory behind integrated MD-PhD training as the basis for designing interventions and evaluations to develop the foundations of physician-scientist expertise.

Diffusion tensor imaging of neurocognitive profiles in a community cohort living in marginal housing

OBJECTIVE

We investigated white matter differences associated with distinct neurocognitive profiles derived from a large cohort of marginally housed persons with comorbid physical and mental illnesses. Our prior work identified three profile cluster groups: a high functioning group (Cluster 1), a low functioning group with relative strength in decision-making (Cluster 3), and an intermediary group with a relative decision-making weakness (Cluster 2). This study extends previous findings of cortical gray matter differences between these groups with evidence for putative neurodevelopmental abnormalities in the low cognitive functioning group (i.e., Cluster 3). We hypothesized that altered white matter diffusion would be associated with the lowest functioning neurocognitive profile and would be associated with previously observed gray matter differences.

METHOD

Participants from a socially impoverished neighborhood in Vancouver, Canada underwent neurocognitive evaluation and neuroimaging. We performed Tract-Based Spatial Statistics using diffusion tensor imaging data from 184 participants to examine whole-brain differences in white matter microstructure between cluster analytically derived neurocognitive profiles, as well as unitary neurocognitive measures. Correlations between frontal gray and white matter were also examined.

RESULTS

Cluster 3 showed increased diffusion in predominately bilateral frontal and interhemisphere tracts (vs. Clusters 1 and 2), with relatively greater diffusion in the left hemisphere (vs. Cluster 1). Differences in radial diffusivity were more prominent compared with axial diffusivity. A weak association between regional frontal fractional anisotropy and previously defined abnormalities in gyrification was observed.

CONCLUSIONS

In a socially marginalized sample, we established several patterns in the covariation of white matter diffusion and neurocognitive functioning. These patterns elucidate the neurobiological substrates and vulnerabilities that are apt to underlie functional impairments inherent to this complex and heterogeneous population.

Clinical and functional characteristics of young adults living in single room occupancy housing: preliminary findings from a 10-year longitudinal study

OBJECTIVE

Young adults living in single room occupancy (SRO) hotels, a form of low-income housing, are known to have complex health and substance problems compared to their peers in the general population. The objective of this study is to comprehensively describe the mental, physical, and social health profile of young adults living in SROs.

METHODS

This study reports baseline data from young adults aged 18-29 years, as part of a prospective cohort study of adults living in SROs in Vancouver, British Columbia, Canada. Baseline and follow-up data were collected from 101 young adults (median follow-up period 1.9 years [IQR 1.0-3.1]). The comprehensive assessment included laboratory tests, neuroimaging, and clinician- and patient-reported measures of mental, physical, and social health and functioning.

RESULTS

Three youth died during the preliminary follow-up period, translating into a higher than average mortality rate (18.6, 95% CI 6.0, 57.2) compared to age- and sex-matched Canadians. High prevalence of interactions with the health, social, and justice systems was reported. Participants were living with median two co-occurring illnesses, including mental, neurological, and infectious diseases. Greater number of multimorbid illnesses was associated with poorer real-world functioning (ρ = - 0.373, p < 0.001). All participants reported lifetime alcohol and cannabis use, with pervasive use of stimulants and opioids.

CONCLUSION

This study reports high mortality rates, multimorbid illnesses, poor functioning, poverty, and ongoing unmet mental health needs among young adults living in SROs. Frequent interactions with the health, social, and justice systems suggest important points of intervention to improve health and functional trajectories of this vulnerable population.

Rapid Change in Fentanyl Prevalence in a Community-Based, High-Risk Sample

This prospective longitudinal analysis of people living in an impoverished neighborhood finds that fentanyl-positive urine samples increased rapidly during a 5-month period while opiate-positive samples declined.

The Hotel Study-Clinical and Health Service Effectiveness in a Cohort of Homeless or Marginally Housed Persons

OBJECTIVE

The Hotel Study was initiated in Vancouver's Downtown East Side (DTES) neighborhood to investigate multimorbidity in homeless or marginally housed people. We evaluated the clinical effectiveness of existing, illness-specific treatment strategies and assessed the effectiveness of health care delivery for multimorbid illnesses.

METHOD

For context, we mapped the housing locations of patients presenting for 552,062 visits to the catchment hospital emergency department (2005-2013). Aggregate data on 22,519 apprehensions of mentally ill people were provided by the Vancouver Police Department (2009-2015). The primary strategy was a longitudinal cohort study of 375 people living in the DTES (2008-2015). We analysed mortality and evaluated the clinical and health service delivery effectiveness for infection with human immunodeficiency virus or hepatitis C virus, opioid dependence, and psychosis.

RESULTS

Mapping confirmed the association between poverty and greater number of emergency visits related to substance use and mental illness. The annual change in police apprehensions did not differ between the DTES and other policing districts. During 1581 person-years of cohort observation, the standardized mortality ratio was 8.43 (95% confidence interval, 6.19 to 11.50). Physician visits were common (84.3% of participants over 6 months). Clinical treatment effectiveness was highest for HIV/AIDS, intermediate for opioid dependence, and lowest for psychosis. Health service delivery mechanisms provided examples of poor access, poor treatment adherence, and little effect on multimorbid illnesses.

CONCLUSIONS

Clinical effectiveness was variable, and illness-specific service delivery appeared to have little effect on multimorbidity. New models of care may need to be implemented.

MD/PhD Training in Canada: Results from a national trainee and program director review

PURPOSE

There has been limited examination of clinician scientist training in Canada, particularly regarding training integration and funding. This study assessed program structure, funding, tuition and mentorship structures available at Canadian MD/PhD programs.

METHODS

Clinician Investigator Trainee Association of Canada administered an anonymous survey to current trainees and program directors that captured program structure, trainee funding, tuition and mentorship opportunities and needs across institutions.

RESULTS

In June 2015, 101/228 (44%) trainees and 9/13 (69%) program directors completed the online survey. In all programs, students completed the PhD degree prior to clerkship training. Seven programs offered research training upon completion of pre-clerkship, four offered concurrent clinical and research training, and three offered alternative structures. Nine held seminars exposing students to clinical and research integration and two offered clinician scientist skills courses. Stipend funding and tuition varied, especially during clinical training years. Regarding mentorship, all programs held regular meetings, though eight programs do not have formal mentorship opportunities. Both trainees and program directors identified the need for further career planning and development support as a student priority.

CONCLUSION

MD/PhD programs varied by program structure, funding, tuition and mentorship opportunities. Mechanisms to share and spread program innovations should be instated. Students may benefit from concurrent research and clinical training as well as courses specific to clinician scientist skill development. Decreasing debt burden may attract and retain trainees in this demanding path. To ensure mentorship programs align with trainee priorities, program directors should directly collaborate with students in their development and evaluation.

Factors affecting severity of positive and negative symptoms of psychosis in a polysubstance using population with psychostimulant dependence

Approximately half of psychostimulant users experience psychotic symptoms, which include both positive and negative symptoms. Prior reports have exclusively used positive symptoms to characterize psychostimulant associated psychosis. Symptoms vary dramatically in severity, though most investigations categorize psychosis as a dichotomous occurrence. To explore the association between different substances of abuse and the severity of psychotic symptoms, we investigated 171 individuals meeting DSM-IV-TR criteria for psychostimulant (cocaine or methamphetamine) dependence in an observational cross-sectional study. Participants were predominantly male (72.5%), recruited from a socially disadvantaged neighborhood in Vancouver, Canada, with a mean age of 45.5(±8.8) years. Of the total sample, 85% were dependent on cocaine, and 28.1% were dependent on methamphetamine. Participants had a median total PANSS score of 63, ranging from 37 to 111. Demographic information, current substance use and early substance exposure were used to predict positive and negative psychotic symptom severity in linear regression models. Increased severity of positive psychotic symptoms was significantly related to greater methamphetamine and marijuana use in the past 28 days, and methadone-abstinence. Negative symptom severity was related to increased opioid use in the past 28 days. There was no overlap between predictors of positive and negative symptom severity.

Mortality from treatable illnesses in marginally housed adults: a prospective cohort study

OBJECTIVES

Socially disadvantaged people experience greater risk for illnesses that may contribute to premature death. This study aimed to evaluate the impact of treatable illnesses on mortality among adults living in precarious housing.

DESIGN

A prospective cohort based in a community sample.

SETTING

A socially disadvantaged neighbourhood in Vancouver, Canada.

PARTICIPANTS

Adults (N=371) living in single room occupancy hotels or recruited from the Downtown Community Court and followed for median 3.8 years.

MAIN OUTCOME MEASURES

Participants were assessed for physical and mental illnesses for which treatment is currently available. We compared cohort mortality rates with 2009 Canadian rates. Left-truncated Cox proportional hazards modelling with age as the time scale was used to assess risk factors for earlier mortality.

RESULTS

During 1269 person-years of observation, 31/371 (8%) of participants died. Compared with age-matched and sex-matched Canadians, the standardised mortality ratio was 8.29 (95% CI 5.83 to 11.79). Compared with those that had cleared the virus, active hepatitis C infection was a significant predictor for hepatic fibrosis adjusting for alcohol dependence and age (OR=2.96, CI 1.37 to 7.08). Among participants <55 years of age, psychosis (HR=8.12, CI 1.55 to 42.47) and hepatic fibrosis (HR=13.01, CI 3.56 to 47.57) were associated with earlier mortality. Treatment rates for these illnesses were low (psychosis: 32%, hepatitis C virus: 0%) compared with other common disorders (HIV: 57%, opioid dependence: 61%) in this population.

CONCLUSIONS

Hepatic fibrosis and psychosis are associated with increased mortality in people living in marginal conditions. Timely diagnosis and intervention could reduce the high mortality in marginalised inner city populations.

Response trajectories to clozapine in a secondary analysis of pivotal trials support using treatment response to subtype schizophrenia

OBJECTIVE

Groups of nonrefractory patients with schizophrenia, taking antipsychotics other than clozapine, show distinct trajectories of treatment response over time. Whether similar patterns of response occur with clozapine-treated patients remains uncertain.

METHOD

We used a cluster analysis approach for longitudinal data (k-means longitudinal) to analyze individual patient data from 2 pivotal studies of clozapine, compared with chlorpromazine. Trajectories and symptom severity were examined in a younger, less chronic, mixed-sample (study 16, n=100) and in treatment-refractory (study 30, n=257) patients.

RESULTS

Early-good and delayed-partial trajectory groups were observed, with the early-good trajectory group comprised of 73/100 (73.0%) from the mixed patient study, and 147/257 (57.2%) refractory patients. In the mixed patient sample, the distribution of clozapine and chlorpromazine treatments did not differ between the early-good and delayed-partial trajectory groups; in refractory patients proportionately more clozapine treatment was present in the early-good (87/147, 59.2%), compared with the delayed-partial (35/110, 31.8%), trajectory group. In the early-good trajectory group, improvement in mean symptom severity was 63% in mixed-study patients. Clozapine resistance appeared to be present in 10/50 (20.0%) mixed-study patients, and in 35/122 (28.9%) refractory patients.

CONCLUSIONS

Early-good and delayed-partial response trajectories are seen in clozapine studies. The advantage of clozapine over chlorpromazine is seen most clearly in previous refractory patients, within the early-good trajectory group. Good and partial or poor responders to clozapine may merit further investigation.

GluN2B-containing NMDA receptors blockade rescues bidirectional synaptic plasticity in the bed nucleus of the stria terminalis of cocaine self-administering rats

Drugs of abuse have detrimental effects on homeostatic synaptic plasticity in the motivational brain network. Bidirectional plasticity at excitatory synapses helps keep neural circuits within a functional range to allow for behavioral flexibility. Therefore, impaired bidirectional plasticity of excitatory synapses may contribute to the behavioral hallmarks of addiction, yet this relationship remains unclear. Here we tracked excitatory synaptic strength in the oval bed nucleus of the stria terminalis (ovBNST) using whole-cell voltage-clamp recordings in brain slices from rats self-administering sucrose or cocaine. In the cocaine group, we measured both a persistent increase in AMPA to NMDA ratio (A:N) and slow decay time of NMDA currents throughout the self-administration period and after withdrawal from cocaine. In contrast, the sucrose group exhibited an early increase in A:N ratios (acquisition) that returned toward baseline values with continued self-administration (maintenance) and after withdrawal. The sucrose rats also displayed a decrease in NMDA current decay time with continued self-administration (maintenance), which normalized after withdrawal. Cocaine self-administering rats exhibited impairment in NMDA-dependent long-term depression (LTD) that could be rescued by GluN2B-containing NMDA receptor blockade. Sucrose self-administering rats demonstrated no impairment in NMDA-dependent LTD. During the maintenance period of self-administration, in vivo (daily intraperitoneally for 5 days) pharmacologic blockade of GluN2B-containing NMDA receptors did not reduce lever pressing for cocaine. However, in vivo GluN2B blockade did normalize A:N ratios in cocaine self-administrating rats, and dissociated the magnitude of ovBNST A:N ratios from drug-seeking behavior after protracted withdrawal. Altogether, our data demonstrate when and how bidirectional plasticity at ovBNST excitatory synapses becomes dysfunctional with cocaine self-administration and that NMDA-mediated potentiation of AMPA receptors in this region may be part of the neural circuits of drug relapse.

Dopamine decreases NMDA currents in the oval bed nucleus of the stria terminalis of cocaine self-administering rats

Dopamine (DA) and N-methyl-D-aspartate receptors (NMDARs) contribute in the neural processes underlying drug-driven behaviors. DA is a potent modulator of NMDAR, but few studies have investigated the functional interaction between DA and NMDAR in the context of substance abuse. We combined the rat model of cocaine self-administration with brain slice electrophysiology to study DA modulation of NMDA currents in the oval bed nucleus of the stria terminalis (ovBNST), a dense DA terminal field involved in maintenance of cocaine self-administration amongst other drug related behaviors. Long-Evans rats self-administered intravenous cocaine (0.75 mg/kg/injection) on a progressive ratio (PR) schedule of reinforcement for 15 days and whole-cell patch-clamp recordings were done on the 16th day. DA reduced NMDA currents in brain-slices from cocaine self-administering rats, but not in those of drug-naïve and sucrose self-administering, or when cocaine exposure was passive (yoked), revealing a mechanism unique to voluntary cocaine intake. DA reduced NMDA currents by activating G-protein-coupled D1- and D2-like receptors that converged on phospholipase C and protein phosphatases. Accordingly, our study reveals a mechanism that may contribute to dysfunctional synaptic plasticity associated with drug-driven behaviors during acute withdrawal.

Mapping loss of heterozygosity in normal human breast cells from BRCA1/2 carriers

We have studied loss of heterozygosity at the BRCA1 and BRCA2 loci in 992 normal cell clones derived from topographically defined areas of normal tissue in four samples from BRCA1/BRCA2 mutation carriers. The frequency of loss of heterozygosity in the clones was low (1.01%), but it was found in all four samples, whether or not a tumour was present. Topographical mapping revealed that the genetic changes were clustered in some breast samples. Our study confirms the previous finding that a field of genetic instability can exist around a tumour, suggesting that sufficient tissue must be removed at surgery to avoid local recurrence. We also demonstrate that such a field of genetic change can exist in morphologically normal tissue before a tumour develops and, for the first time, we demonstrate that the field is of a size greater than one terminal duct-lobular unit. The genetic changes are not identical, however, which suggests that genetic instability in these regions may play an early role in tumour development. We also confirm and extend our original observation of loss of the wild-type BRCA1 allele in some clones, and loss of the mutant allele in others, demonstrating that loss of either allele is a stochastic event.

Evaluation of recombinant human bone morphogenetic protein-2 in oral applications including the use of endosseous implants: 3-year results of a pilot study in humans

BACKGROUND

This study evaluated patients who had been treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded in an absorbable collagen sponge (ACS) in human extraction sites or in sites that required alveolar ridge augmentation. An earlier report on the same patients revealed that after 4 months, implantation of rhBMP-2/ACS was safe, as determined by clinical, radiographic, systemic, and immunological analyses. In this longer-term follow-up, eligible patients were restored with endosseous dental implants in the area treated with rhBMP-2/ACS and bone biopsy samples were taken for histological analysis of the treated human bone tissue. The primary objective was to monitor the long-term safety of patients treated with rhBMP-2/ACS. Another objective was to evaluate the dental implants placed in the sites treated with rhBMP-2.

METHODS

Patient safety was evaluated by clinical examinations, periapical radiographs, and occurrence of adverse experiences. Dental implants were evaluated by radiographic and clinical examination. All 12 patients have been followed for 3 years.

RESULTS

Two years following surgical implantation of rhBMP-2/ACS, no serious or unexpected adverse experiences occurred. The adverse experiences that did occur were mostly benign and compatible with the dental implant surgeries performed in these patients. No adverse experiences were deemed as related to the rhBMP-2/ACS. Furthermore, no safety concerns in the local area of rhBMP-2/ACS placement were noted, based on oral wound examinations. In the 10 patients (6 extraction socket patients and 4 augmentation patients) who received endosseous implants, all implants were clinically stable at all assessments and all 10 patients have been functionally restored. Histological evaluation of the human bone core biopsies revealed normal bone tissue formation identical to the surrounding native bone. Three-year follow-up clinical examinations revealed that all implants had stable marginal bone levels and healthy peri-implant tissues.

CONCLUSIONS

These 3-year results demonstrate that rhBMP-2/ACS can be used safely in human patients. Human bone biopsies reveal normal bone formation in areas treated with rhBMP-2/ACS. Endosseous implants placed in these areas were all stable with no radiographic or clinical complications. The results from this study suggest that rhBMP-2/ACS (0.43 mg/ml) can be safely used in tooth extraction sites and in local ridge augmentation procedures and that endosseous dental implants placed in bony areas treated with rhBMP-2/ACS are stable and can be functionally restored without complication.

Volunteer services for vulnerable families and at-risk elderly

OBJECTIVE

The purpose of this paper is to explore the role of the volunteer with vulnerable populations, specifically, new parents and their infants and at-risk elderly. As demand for volunteer services increases due to budgetary and personnel reductions, a better understanding of volunteers as service providers is imperative.

METHOD

A review of the literature related to volunteers who work with these two populations was conducted. Volunteer characteristics, roles, needs of populations served, recruitment, and training issues were addressed, specifically as they relate to the two populations.

RESULTS

Studies indicate that the socio-demographic range of volunteers is wide, as are the motivations for volunteering. Similarities between the needs of new families and the elderly exist, and volunteers for both populations often provide supportive and pragmatic services. Volunteers for both populations are further challenged to maintain a client-focused intervention, a task which may be more difficult in the home. Training of volunteers was found to be both client and volunteer driven, with the needs of the population being served and the role of the volunteer within a specific service domain of prime importance.

CONCLUSION

Similarities between infant and elder populations exist, as do volunteer interventions with these populations. A theoretical framework for defining motivation, designing need-based training, and addressing the role of volunteers is discussed. The use of volunteers as compassionate and cost-effective service providers for populations across the lifespan not only provides an increase in the number of skilled workers involved with these vulnerable populations, but also allows professional staff to expand the care which they are able to provide.

Linking lost voices: reading 'The Dead'

The author presents an individual reading of James Joyce's short story. 'The Dead' from 'Dubliners'. Language evokes subjective responses and associations that become part of the depth of experience one finds in a book. The author describes how uses of language give the reader a sense of sharing the main character's experience. She focuses on nodal moments in the story, in which external and internal worlds intersect. Images focused on include those of seeing and touching, inside and outside, crossing gaps between worlds and the way in which these sensory events shift the character's knowledge of his internal objects. The metaphor of lost voices highlights the presence of the dead throughout the story. The main character's evolution from being in a constricted state to one of expanded self-awareness is discussed. Britton's concept of triangular space is used to describe the character's transformation at the story's conclusion.

Recombinant human bone morphogenetic protein-2 stimulation of bone formation around endosseous dental implants

BACKGROUND

Successful endosseous implant placement requires that the implant be stable in alveolar bone. In certain cases, the implant can be stabilized in native bone but some part of the implant is not covered by bone tissue. This often occurs during placement of implants into extraction sites or in areas where bone resorption has occurred and the ridge width is not sufficient to completely surround the implant. In those cases, the clinician usually employs a procedure to encourage bone formation. These procedures typically include a bone graft and/or membrane therapy. Recent advances have led to the isolation, cloning, and production of recombinant human proteins that stimulate bone formation. One of these bone morphogenetic proteins (rhBMP-2) has been extensively studied in animal models and is currently being tested in human clinical trials.

METHODS

In this study, rhBMP-2 was tested using a collagen sponge carrier to stimulate bone formation in defects in the canine mandible around endosseous dental implants. Six animals had a total of 48 implants placed. rhBMP-2 with the collagen carrier was implanted around 24 of these, the remainder having only the collagen carrier placed. Half the sites were covered with a nonresorbable expanded polytetrafluoroethylene membrane. Histologic analysis was performed after 4 and 12 weeks. The area of new bone formed, percentage of bone-to-implant contact in the defect area, and percentage fill of the defect was calculated.

RESULTS

The addition of rhBMP-2 resulted in significantly greater amounts of new bone area and percentage of bone-to-implant contact and with more percentage fill after 4 and 12 weeks of healing. The area of new bone formed was reduced after 4 weeks when a membrane was present but after 12 weeks, there was no significant difference between membrane and non-membrane treated sites. In some specimens, new bone was found coronal to the membranes, with rhBMP-2-treated sites having greater amounts than non-rhBMP-2-treated sites.

CONCLUSIONS

These data demonstrate that a bone differentiation factor significantly stimulates bone formation in peri-implant bone defects in the canine mandible. In addition, bone-to-implant contact was significantly enhanced along the rough implant surface. Membrane-treated sites had less new bone formation after 4 weeks of healing but were similar to non-membrane sites after 12 weeks. These results demonstrate that rhBMP-2 can be used to stimulate bone growth both around and onto the surface of endosseous dental implants placed in sites with extended peri-implant osseous defects.

A 129Xe NMR study on an ionomeric polymer blend system

The morphology of an ionomeric polymer blend consisting of an amino-silicone copolymer and zinc neutralized sulfonated polystyrene (ZnSPS) has been studied using proton spin diffusion and small angle X-ray scattering (SAXS). The extent of reaction between the two components in the blend was monitored by 13C CP MAS spectroscopy. All three types of experiment point to domain sizes in the nanometer range. 129Xe NMR was used to study exchange by translational diffusion between domains. A single xenon resonance was detected in temperatures ranging from 25 degrees C to -90 degrees C, and the chemical shift followed a weighted average of the isolated polymer shifts consistent with the small domain sizes. Pulse field gradient 129Xe NMR was used to determine the effective diffusion constants in the amino silicone starting material and the blend. The diffusion constant of xenon in poly(styrene) is known, allowing for comparison of the predictions of effective diffusion constants in the blend based on the values in the constituents of the blend. Simple two-site exchange equations incorrectly predict that diffusion in the blend would be dominated by the constituent with slow diffusion. The blend diffusion constant is close to the value of the amino silicone or the constituent with fast diffusion which is correctly predicted for a rapid exchange solution of the diffusion equation.

Clinical evaluation of bioactive glass in the treatment of periodontal osseous defects in humans

The purpose of this study was to compare the use of bioactive glass to demineralized freeze-dried bone allograft (DFDBA) in the treatment of human periodontal osseous defects. Fifteen systemically healthy patients (6 males and 9 females, aged 30 to 63) with moderate to advanced adult periodontitis were selected for the study. All patients underwent initial therapy, which included scaling and root planing, oral hygiene instruction, and an occlusal adjustment when indicated, followed by re-evaluation 4 to 6 weeks later. Paired osseous defects in each subject were randomly selected to receive grafts of bioactive glass or DFDBA. Both soft and hard tissue measurements were taken the day of surgery (baseline) and at the 6-month re-entry surgery. The clinical examiner was calibrated and blinded to the surgical procedures, while the surgeon was masked to the clinical measurements. Statistical analysis was performed by using the paired Student's t test. The results indicated that probing depths were reduced by 3.07 +/- 0.80 mm with the bioactive glass and 2.60 +/- 1.40 mm with DFDBA. Sites grafted with bioactive glass resulted in 2.27 +/- 0.88 mm attachment level gain, while sites grafted with DFDBA had a 1.93 +/- 1.33 mm gain in attachment. Bioactive glass sites displayed 0.53 +/- 0.64 mm of crestal resorption and 2.73 mm bone fill. DFDBA-grafted sites experienced 0.80 +/- 0.56 mm of crestal resorption and 2.80 mm defect fill. The use of bioactive glass resulted in 61.8% bone fill and 73.33% defect resolution. DFDBA-grafted defects showed similar results, with 62.5% bone fill and 80.87% defect resolution. Both treatments provided soft and hard tissue improvements when compared to baseline (P < or = 0.0001). No statistical difference was found when comparing bioactive glass to DFDBA; however, studies with larger sample sizes may reveal true differences between the materials. This study suggests that bioactive glass is capable of producing results in the short term (6 months) similar to that of DFDBA when used in moderate to deep intrabony periodontal defects.

Randomized, placebo-controlled trial of platelet glycoprotein IIb/IIIa blockade with primary angioplasty for acute myocardial infarction. ReoPro and Primary PTCA Organization and Randomized Trial (RAPPORT) Investigators

BACKGROUND

The benefit of catheter-based reperfusion for acute myocardial infarction (MI) is limited by a 5% to 15% incidence of in-hospital major ischemic events, usually caused by infarct artery reocclusion, and a 20% to 40% need for repeat percutaneous or surgical revascularization. Platelets play a key role in the process of early infarct artery reocclusion, but inhibition of aggregation via the glycoprotein IIb/IIIa receptor has not been prospectively evaluated in the setting of acute MI.

METHODS AND RESULTS

Patients with acute MI of <12 hours' duration were randomized, on a double-blind basis, to placebo or abciximab if they were deemed candidates for primary PTCA. The primary efficacy end point was death, reinfarction, or any (urgent or elective) target vessel revascularization (TVR) at 6 months by intention-to-treat (ITT) analysis. Other key prespecified end points were early (7 and 30 days) death, reinfarction, or urgent TVR. The baseline clinical and angiographic variables of the 483 (242 placebo and 241 abciximab) patients were balanced. There was no difference in the incidence of the primary 6-month end point (ITT analysis) in the 2 groups (28.1% and 28.2%, P=0.97, of the placebo and abciximab patients, respectively). However, abciximab significantly reduced the incidence of death, reinfarction, or urgent TVR at all time points assessed (9.9% versus 3.3%, P=0.003, at 7 days; 11.2% versus 5.8%, P=0.03, at 30 days; and 17.8% versus 11.6%, P=0.05, at 6 months). Analysis by actual treatment with PTCA and study drug demonstrated a considerable effect of abciximab with respect to death or reinfarction: 4.7% versus 1.4%, P=0.047, at 7 days; 5.8% versus 3.2%, P=0.20, at 30 days; and 12.0% versus 6.9%, P=0.07, at 6 months. The need for unplanned, "bail-out" stenting was reduced by 42% in the abciximab group (20.4% versus 11.9%, P=0.008). Major bleeding occurred significantly more frequently in the abciximab group (16.6% versus 9.5%, P=0.02), mostly at the arterial access site. There was no intracranial hemorrhage in either group.

CONCLUSIONS

Aggressive platelet inhibition with abciximab during primary PTCA for acute MI yielded a substantial reduction in the acute (30-day) phase for death, reinfarction, and urgent target vessel revascularization. However, the bleeding rates were excessive, and the 6-month primary end point, which included elective revascularization, was not favorably affected.

Risk of blood contamination of health care workers in spine surgery. A study of 324 cases

STUDY DESIGN

The relative risk of blood contamination during spine surgery was studied using data collected from 324 procedures.

OBJECTIVES

To analyze demographic factors that predict blood-borne pathogens in the population of spine surgery patients, study the rates and patterns of blood contamination in health care workers (i.e., skin-penetrating incidents and nonpenetrating surface skin contamination from patients' blood) and compare those risks with those in other surgical departments, and analyze the effectiveness of barrier systems worn by the surgical team.

SUMMARY OF BACKGROUND DATA

The Centers for Disease Control and Prevention has reported 49 health care workers infected by the human immunodeficiency virus through occupational exposure. Several studies have noted the risk of blood contamination in various surgical departments, but the relative risk during spine surgery has not been determined.

METHODS

This year-long survey included 9795 cases, or 60,789 health care worker--patient contacts, of which spine disorders comprised 324 cases (2234 health care workers and patients). Data collection forms were designed and inservice training conducted with operating room staffs. Information regarding type of case, staff position (surgeon, assistant, scrub nurse, circulator), protective clothing worn, length of operating room time, blood loss, incidence of blood spills, was recorded, among other data.

RESULTS

Prevalence of human immunodeficiency virus in patients in the overall series was 0.19% versus 0.93% in spine patients. The rate of HCW contamination in the overall series was 7.76%, of which 0.92% resulted from skin-penetrating incidents. Contamination in spine surgery occurred in 31.86% of cases, of which 1.23% were the result of skin-penetrating incidents.

CONCLUSIONS

Health care workers in spine surgery have a statistically significant overall higher risk of blood contamination than do those in other surgical departments. The increased risk occurred with blood contacting intact skin. There was no higher risk for skin penetrating injury. Analysis of data suggests that health care workers always should wear double gloves, forearm-reinforced gowns, and eye protection.

Copper supplementation of adult men: effects on blood copper enzyme activities and indicators of cardiovascular disease risk

In rats, copper deficiency leads to low copper metalloenzyme activity, high serum cholesterol, and cardiovascular lesions. In humans, moderately low copper intake may be common, but the consequences remain largely uncertain. The present study examined the effects of copper supplementation (2 mg/d for 4 weeks in a copper/placebo crossover design) in 20 adult men with moderately high plasma cholesterol. End-point measurements were three copper enzyme activities, erythrocyte superoxide dismutase (SOD), plasma ceruloplasmin (Cp), and plasma diamine oxidase (DAO), and three parameters related to the risk of cardiovascular disease (CVD), plasma cholesterol, plasma lipoprotein (a) [Lp(a)], and lag times for very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) oxidation in vitro. Although copper had no significant effects on any parameter for the entire study group, it did significantly increase two enzyme activities (SOD and DAO), as well as lipoprotein oxidation lag times, in 10 subjects in the lower half of a median split for precopper values. Thus, copper supplementation appeared to influence some types of measurements in subjects beginning with less than median values.

Radiographic analysis of regenerated bone around endosseous implants in the canine using recombinant human bone morphogenetic protein-2

Ideal endosseous implant placement involves a congruent bony housing in close apposition to the implant surface. Clinical situations are encountered, however, in which the entire implant surface cannot be in close apposition to bone. In these instances, bone grafting materials are generally used to regenerate bone around the implant. In this study, a biologically active bone differentiation factor, recombinant human bone morphogenetic protein-2 (rhBMP-2), was used with two different carriers to regenerate bone around implants in standardized critical-sized defects in the canine mandible. Half of the sites had a nonresorbable membrane placed over the defect. Longitudinal standardized radiographs were obtained to assess the amount of bone regeneration on the mesial and distal of the implants after 4 and 12 weeks of healing. Ninety-six implants were placed in 12 fox-hounds. Bone fill was determined by linear measurement of bone on the radiographs, and changes in bone density were evaluated by computer-assisted densitometric image analysis of discrete areas adjacent to the implant. After 4 weeks of healing, nonmembrane sites had significantly greater bone height than membrane-protected sites. Following 12 weeks of healing, sites treated with rhBMP-2 had significantly greater bone formation than untreated sites. Sites treated with rhBMP-2 and a membrane had the greatest bone fill, followed by sites treated with rhBMP-2 but no membrane. Sites without rhBMP-2, whether with or without a membrane, had less bone fill than sites with rhBMP-2. At 12 weeks, sites with a membrane resulted in significantly more gain in bone density than sites without a membrane. Furthermore, sites treated with a collagen carrier resulted in greater gains in bone density than sites treated with a polylactide/glycolide carrier. The results from this study demonstrate by radiographic evidence that new bone formation in critical-sized defects around implants is dependent on time after defect treatment, the type of carrier used, the use of a barrier membrane, and the presence of rhBMP-2. In addition, these findings suggest that rhBMP-2, a bone differentiation factor, can significantly stimulate bone formation around endosseous dental implants.

Experiencing language: some thoughts on poetry and psychoanalysis

The author uses her experiences as a poet and as a psychoanalyst to compare the two. She discusses poems by James Merrill, Philip Larkin, and Theodore Roethke in order to consider how the analyst listens, how the poet writes, how each listens to what is unsaid in the music of language. Rhythm, meter, and the sounds of words constitute this music. Sound and image are means by which language bypasses logic and touches us. Considering how a poem has an impact can teach us something about how words affect us in psychoanalysis.