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Biomedical subjects

R E Roberts

Publications and source records attributed to R E Roberts.

At least 37 records · Page 2Linked to original sources

Factors associated with suicide ideation among American Indian adolescents: does culture matter?

Data from self-report surveys of 1,353 high school students representing three culturally distinct American Indian tribes were analyzed for tribal differences in factors associated with suicidal ideation. In the multivariate analysis, no single correlate of suicide ideation was common to all three tribes. The correlates of suicide ideation were consistent with each tribe's social structure, conceptualization of individual and gender roles, support systems, and conceptualization of death. These results underscore the heterogeneity of suicide ideation across three distinct American Indian tribes consistent with their cultural heterogeneity. Suicide prevention and screening programs may be difficult to adapt from one tribe to another.

Adolescent↗

Depressive symptoms and increased risk of stroke mortality over a 29-year period.

BACKGROUND: Several lines of evidence indicate that depression is importantly associated with cardiovascular disease end points. However, little is known about the role of depression in stroke mortality. METHODS: This study examined the association between depressive symptoms and stroke mortality in a prospective study of behavioral, social, and psychological factors related to health and mortality in a community sample of 6676 initially stroke-free adults (45.8% male; 79.1% white; mean age at baseline, 43.4 years) from Alameda County, California. Depressive symptoms were assessed by the 18-item Human Population Laboratory Depression Scale. Cox proportional hazards regression models were used to evaluate the impact of depressive symptoms after controlling for age, sex, race, and other confounders. RESULTS: A total of 169 stroke deaths occurred during 29 years of follow-up. Reporting 5 or more depressive symptoms at baseline was associated with increased risk of stroke mortality, after adjusting for age, sex, and race (hazard ratio, 1.66; 95% confidence interval, 1.16-2.39; P<.006). This association remained significant after additional adjustments for education, alcohol consumption, smoking, body mass index, hypertension, and diabetes (hazard ratio, 1.54; 95% confidence interval, 1.06-2.22; P<.02). Time-dependent covariate models, which allowed changes in reported depressive symptoms and risk factor levels during follow-up, revealed the same pattern of associations. CONCLUSIONS: This population-based study provides the strongest epidemiological evidence to date for a significant relationship between depressive symptoms and stroke mortality. These results contribute to the growing literature on the adverse health effects of depression.

Adult↗

Perception of discrimination and ethnocultural variables in a diverse group of adolescents.

Despite current interest in the multi-dimensionality of culture and ethnicity there are few studies that have explored the role of discrimination with ethnocultural variables. In this study social identity theory was used as a framework to test the relation between discrimination and components of ethnic identity, and attitudes towards out-groups. A school-based survey in a large south-west metropolitan area in 1994 was undertaken with students (n=3071) of African-American, European-American, Mexican-American, and Vietnamese-American descent using multiple measures of ethnicity. Hierarchical multiple regression results indicated that two components of ethnic identity played different roles in the relation between discrimination and attitudes towards others. Consistent with social identity theory, results indicated that perception of more discrimination was predicted by high ethnic exploration, and having more negative attitudes towards out-groups. However, ethnic affirmation, which is a positive sense of belonging to one's ethnic group, was only indirectly related to discrimination through attitudes toward others. In fact, contrary to social identity theory, a stronger sense of belonging to one's group was associated with more positive attitudes toward out-groups. Results have important implications for race relations.

Acculturation↗

Alpha2-adrenoceptor-mediated contractions of the porcine isolated ear artery: evidence for a cyclic AMP-dependent and a cyclic AMP-independent mechanism.

1. The aim of this study was to determine the conditions under which the alpha2-adrenoceptor agonist UK14304 produces vasoconstriction in the porcine isolated ear artery. 2. UK14304 (0.3 microM) produced a small contraction of porcine isolated ear arteries which was 7.8+/-3.3% of the response to 60 mM KCl. Similar sized contractions were obtained after precontraction with either 30 nM angiotensin II, or 0.1 microM U46619 (8.2+/-1.8% and 10.2+/-2.6% of 60 mM KCl response, respectively). However, an enhanced alpha2-adrenoceptor response was uncovered if the tissue was precontracted with U46619, and relaxed back to baseline with 1-2 microM forskolin before the addition of UK14304 (46.9+/-9.6% of 60 mM KCl response). 3. The enhanced responses to UK14304 in the presence of U46619 and forskolin were not inhibited by the alpha1-adrenoceptor antagonist prazosin (0.1 microM), but were inhibited by the alpha2-adrenoceptor antagonist rauwolscine (1 microM), indicating that the enhanced responses were mediated via postjunctional alpha2-adrenoceptors. 4. In the presence of 0.1 microM U46619 and 1 mM isobutylmethylxanthine (IBMX), 1 microM forskolin produced an increase in [3H]-cyclic AMP levels in porcine isolated ear arteries. Addition of 0.3 microM UK14304 prevented this increase. 5. The enhanced UK14304 response was dependent upon the agent used to relax the tissue. After relaxation of ear arteries precontracted with 10 nM U46619 and relaxed with forskolin the UK14304 response was 46.9+/-9.6% of the 60 mM KCl response, and after relaxation with sodium nitroprusside (SNP) the response was 24.8+3.3%. However, after relaxation of the tissue with levcromakalim the UK14304 response was only 8.2+/-1.7%, which was not different from the control response in the same tissues (12.2+/-5.6%). An enhanced contraction was also obtained after relaxation of the tissue with the cyclic AMP analogue dibutyryl cyclic AMP (23.2+/-1.3%) indicating that at least part of the enhanced response to UK14304 is independent of the ability of the agonist to inhibit cyclic AMP production. 6. Relaxation of U46619 contracted ear arteries with SNP could be inhibited by the NO-sensitive guanylyl-cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) indicating that production of cyclic GMP is necessary for the relaxant effect of SNP. However, ODQ had no effect on the relaxation of tissue by forskolin, suggesting that this compound does not act via production of cyclic GMP. Biochemical studies showed that while forskolin increases the levels of cyclic AMP in the tissues, SNP had no effect on the levels of this cyclic nucleotide. 7. In conclusion, enhanced contractions to the alpha2-adrenoceptor agonist UK14304 can be uncovered in porcine isolated ear arteries by precontracting the tissue with U46619, followed by relaxation back to baseline with forskolin, SNP or dibutyryl cyclic AMP before addition of UK14304. There was a greater contractile response to UK14304 after relaxation with forskolin than with SNP or dibutyryl cyclic AMP, suggesting that cyclic AMP-dependent and- independent mechanisms are involved in the enhancement of the UK14304 response.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

Religiosity buffers effects of some stressors on depression but exacerbates others.

Although religiosity is protective for mortality and morbidity, its relationship with depression is unclear. We used the 1994 Alameda County Study survey of 2,537 subjects aged 50-102 to analyze associations between two forms of religiosity and depression as well as the extent to which religiosity buffers relationships between stressors and depression. Non-organizational religiosity included prayer and importance of religious and spiritual beliefs; organizational religiosity included attendance at services and other activities. Non-organizational religiosity had no association with depression; organizational religiosity had a negative relationship that weakened slightly with the addition of health controls. Both forms of religiosity buffered associations with depression for non-family stressors, such as financial and health problems. However, non-organizational religiosity exacerbated associations with depression for child problems, and organizational religiosity exacerbated associations with depression for marital problems, abuse, and caregiving. Religiosity may help those experiencing non-family stressors, but may worsen matters for those facing family crises.

Aged↗

Suicidal thinking among adolescents with a history of attempted suicide.

OBJECTIVE: To examine the risk of suicidal plans and ideation, depression, and other factors (low self-esteem, loneliness, fatalism, pessimism) among adolescents with a lifetime history of attempted suicide. METHOD: A self-administered questionnaire was used in a school-based survey of five middle schools (grades 6 through 8) enrolling 6,400 students. Usable questionnaires were obtained from 5,423 (85.3%). Data were obtained on a wide range of constructs including recent and lifetime suicide attempts, recent and lifetime suicide plans, recent ideation, symptoms of DSM-IV major depression, self-esteem, pessimism, loneliness, and fatalism. RESULTS: Data on crude prevalence showed thoughts about death, wishing to be dead, thoughts of suicide, and suicide plans were all significantly higher among youths with a history of attempts. Suicidal thinking was related to being more lonely, more fatalistic, and more pessimistic, and to less self-esteem, in addition to depression and a history of attempts. Multivariate analyses revealed the strongest factors associated with current suicidal thinking were history of attempts (odds ratio [OR] = 3.50), depression (OR = 5.34), and recent life stress (OR = 2.64). Compared with youths with none of the factors examined, those with six or more were at extreme risk (OR = 67.87). CONCLUSIONS: The strong association between history of suicide attempts, current ideation, and depression indicates that past suicide attempts occur in the context of other signs of psychosocial dysfunction. Given the paucity of epidemiological data on the natural history of suicidal behaviors among youths, more epidemiological studies of the antecedents and consequences of the range of suicidal behaviors among children and adolescents are needed. Given the high risk of subsequent suicidal behaviors by youths who have attempted but not completed suicide, this constitutes a high-risk population on which future research should focus.

Adolescent↗

Ethnicity and adolescent depression: the case of Chinese Americans.

This paper is concerned with whether an instrument developed in the U.S. may identify lower rates of major depression among Chinese, because its content may not cover culture-specific symptoms of depression. Data were obtained from approximately 952 Anglo and Chinese American middle school students, aged 10 to 17 years, in the Teen Life Changes Survey conducted in the spring of 1994. We investigated the hypothesis that rates of missing values would be higher, the mean score for total depression items would be lower, and internal consistency reliability and construct validity of the DSM Scale for Depression (DSD) would be lower for Chinese American adolescents compared with Anglo American adolescents. We also examined whether response functions on the DSD item would differ for these two groups. Only the latter was observed. Five of 26 items in the DSD exhibited differential functioning between Anglo and Chinese students. The results suggest that the lower prevalence of depression was not due to the ethnocentric character of the instrument in the Chinese sample. Stronger immunity to depression or other cultural factors may contribute to the lower rate of depression for the Chinese American adolescents in the Teen Life Changes study.

Acculturation↗

Prevalence of psychopathology among children and adolescents.

OBJECTIVE: This study was done to update and expand information given in recent reviews, provide a more systematic critique of past research, identify current research trends and issues, and explore possible strategies for future research in child psychiatric epidemiology. METHOD: The authors identified and reviewed 52 studies done over the past four decades that attempted to estimate the overall prevalence of child and adolescent psychiatric disorders. RESULTS: About as many studies have been published since 1980 as were published before. Sample sizes ranged from 58 to 8,462; most were in the 500-1,000 range. Studies were carried out in over 20 countries, most frequently the United States and the United Kingdom. Subjects' ages ranged from 1 to 18 years. Rutter's criteria were the most frequently used for case definition; more recent studies were more likely to use DSM criteria. The most frequently used interview was the Rutter schedule. The most common time frame for calculating prevalence was the present, followed by 6 months and 1 year. Prevalence estimates of psychopathology ranged from approximately 1% to nearly 51% (mean = 15.8%). Median rates were 8% for preschoolers, 12% for preadolescents, 15% for adolescents, and 18% in studies including wider age ranges. CONCLUSIONS: The evidence is less informative than expected because of several problems that continue to plague research on child and adolescent disorders. These involve sampling, case ascertainment, case definition, and data analyses and presentation. Progress in understanding the epidemiology of child disorders will largely depend on whether future research successfully meets these challenges.

Adolescent↗

Protein kinase C isozyme expression in sciatic nerves and spinal cords of experimentally diabetic rats.

Changes in the expression and activation of protein kinase C (PKC) have been implicated in the pathogenesis of diabetic neuropathy. Recent studies in liver, retina, and cardiovascular tissues from experimentally diabetic rats have demonstrated that diabetes has a selective effect on the expression and subcellular distribution of isozymes of PKC. In the light of this evidence, we investigated the expression of the PKC isozymes alpha, betaI, betaII, and gamma in sciatic nerves, spinal cords, and in the L4,5 dorsal root ganglia from streptozotocin-induced diabetic rats. Six weeks of diabetes had differential effects on the expression and distribution of PKC isozymes in sciatic nerves and spinal cords. In the sciatic nerves there was an apparent translocation of the alpha isoform from the cytosolic to the particulate fractions, the betaII isoform was reduced in the cytosolic fraction, and the betaI and gamma isoforms were unaffected. The changes in the isozyme immunoreactivities in the nerves were not a direct result of changes in either spinal cord or dorsal root ganglia alone, suggesting that diabetes has different effects on motor and sensory fibres and/or on Schwann cells. In nerves that had been crushed 14 days previously there was an increase in total PKC alpha immunoreactivity. This increase was potentiated in diabetic rats. On the other hand, PKC betaII immunoreactivity in crushed nerves was unaffected by diabetes. The data are consistent with diabetes-induced changes in expression of PKC betaII contributing to nerve damage, and changes in PKC alpha being a consequence of it.

Animals↗

Ethnocultural differences in prevalence of adolescent depression.

Data from an ethnically diverse sample of middle school (Grades 6-8) students (n = 5,423) are analyzed for ethnic differences in major depression. The point prevalence of major depression was 8.4% without and 4.3% with impairment. Data were sufficient to calculate prevalences for nine ethnic groups. Prevalences adjusted for impairment ranged from 1.9% for youths of Chinese descent to 6.6% for those of Mexican decent. African and Mexican American youths had significantly higher crude rates of depression without impairment, but only the latter had significantly higher rates of depression with impairment. Multivariate (logistic regression) analyses, adjusting for the effects of age, gender, and socioeconomic status (SES), yielded significant odds ratios for only one group. Mexican American youths were at elevated risk for both depression without (OR = 1.74, p < .05) and depression with impairment (OR = 1.71, p < .05). There was no significant interaction of ethnicity and SES in relation to depression. Females had higher prevalences of depression with and without impairment, as did youths who reported that their SES was somewhat or much worse off than their peers. The data add to growing evidence that Mexican American youths are at increased risk of depression, and that community intervention efforts should specifically target this high-risk group.

Adolescent↗

Center for Epidemiologic Studies Depression Scale (CES-D) as a screening instrument for depression among community-residing older adults.

The efficacy of the Center for Epidemiologic Studies Depression Scale (CES-D) as a screener for clinical depression was examined in a sample of 1,005 community-residing adults (age range = 50-96). Presence of a depressive disorder was determined by diagnostic interview. Analyses revealed that neither age, gender, cognitive impairment, functional impairment, physical disease, nor social desirability had a significant negative effect on the psychometric properties or screening efficacy of the CES-D. These results indicate that there was no significant degradation in the ability of the CES-D to screen for depression among community-residing elderly adults. This conclusion must be tempered by the fact that the sample did not include participants with the more disabling forms of cognitive or functional impairment and physical illness.

Aged↗

Studies of inositol phosphate export from neuronal tissue in vitro.

Recent in vivo microdialysis studies have demonstrated the presence of extracellular levels of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] that can be increased in a concentration-dependent manner by muscarinic receptor activation. The aim of the present study was to determine whether extracellular levels of Ins(1,4,5)P3 could be measured in vitro. Despite rapid increases in internal Ins(1,4,5)P3 levels after stimulation with 1 mM carbachol, there was no change in external levels in both rat brain cortical slices and human neuroblastoma SH-SY5Y cells. Suprafusion of myo-[3H]inositol-prelabelled hippocampal slices with 1 mM carbachol caused an increase in 3H-inositol phosphates over basal levels in the perfusate after 10 min, reaching a peak (223 +/- 56% of basal) 20 min after suprafusion with carbachol was started. This response to carbachol was potentiated in the presence of 30 mM K+. Analysis of the individual 3H-inositol phosphates in the perfusate revealed that levels of [3H]inositol monophosphate, [3H]inositol bisphosphate, [3H]inositol trisphosphate, and [3H]inositol tetrakisphosphate were all significantly increased. A similar increase in extracellular 3H-inositol phosphates was demonstrated in SH-SY5Y cells incubated with 1 mM carbachol for 30 min. This response was again enhanced by 30 mM K+, although the intracellular response was not potentiated. Possible roles for extracellular inositol phosphates are discussed.

Animals↗

Prevalence and correlates of depression in an aging cohort: the Alameda County Study.

Data on symptoms of major depressive episodes were examined for the 1994 cohort (n = 2,417) of the Alameda County Study (mean age = 65). In addition to age, we examined gender, education, marital status, social isolation and social support, perceived physical and mental health, chronic medical conditions, functional impairment, life events, financial strain, and neighborhood quality. The point prevalence of symptoms of major depressive episodes was 6.6 percent for men and 10.1 percent for women, with a trend for prevalence to increase with age. When the effects of the other psychosocial risk factors were controlled, there were no significant age effects. Multivariate analyses demonstrated that apparent initial age effects were due almost entirely to chronic health problems and functional impairment. The implications are clear: Healthy, normal-functioning older adults are at no greater risk of depression than younger adults. Apparent age-related effects on depression are attributable to physical health problems and related disability.

Aged↗

The developmental stake hypothesis and changing perceptions of intergenerational relations, 1971-1985.

This study examines the developmental stake hypothesis as it relates to changing perceptions of intergenerational relations among members of multigenerational families. The data come from the first two waves (1971 and 1985) of a longitudinal study of multigenerational family members (N = 1,057). We find strong support for the developmental stake hypothesis since, at both time periods, parents (both G1s and G2s) saw less distance in their relations with their children (both G2s and G3s). In addition, all respondents perceived less distance between the G2-G3 generations over time. We also found several gender differences in perceptions of family ties. Contrary to our expectations, only G1 respondents perceived less distance between generations in society in 1985 as compared to 1971.

Adolescent↗

Does growing old increase the risk for depression?

OBJECTIVE: Most research examining age as a risk factor for depression has been based on cross-sectional data. To investigate the effect of aging on rates of depression prospectively, the authors used two waves of data from a panel study of community residents 50 years old and older. METHOD: Data on symptoms of major depressive episodes were examined for the 1994 and 1995 cohorts of the Alameda County Study. The authors examined age, gender, marital status, education, financial strain, chronic medical conditions, functional impairment, cognitive problems, life events, neighborhood problems, social isolation, and social support. Depression was measured with 12 items covering DSM-IV diagnostic criteria for major depressive episodes. RESULTS: Point prevalence of major depressive episodes was 8.7% in 1994 and 9.0% in 1995. Among the subjects 60 years old and older, there was a tendency toward higher prevalence in 1995. The highest prevalence rates in 1994 and in 1995 were among those 80 years old and older. Subjects who were depressed in 1994 were at greater risk for depression in 1995. When the effects of age and other psychosocial risk factors in 1994 were controlled, there were no significant age effects on depression in 1995. Multivariate analyses demonstrated that the initial age effects were due mainly to chronic health problems and functional impairment. Gender, chronic health conditions, problems with activities of daily living, cognitive problems, neighborhood problems, and social isolation in 1994 all were significant predictors of depression in 1995. CONCLUSIONS: Healthy, normally functioning older adults are at no greater risk for depression than younger adults. What seem to be age-related effects on depression are attributable to physical health problems and related disability.

Adult↗

Ethnocultural differences in prevalence of adolescent suicidal behaviors.

Data from an ethnically diverse sample of middle school students (grades 6-8; n = 5,423) are analyzed for ethnic differences in suicidal ideation, thoughts about suicide in the past 2 weeks, suicide plans, and suicide attempts. Ideation was examined using a four-item scale and a single item on suicidal thoughts. Ideation was higher among females, older youths, and lower status youths. The same general pattern held for recent suicidal plans and attempts, with the exception of gender, where the trend was for males to report more attempts. Lifetime plans and attempts were higher for females, older youths, and lower status youths. Data were sufficient to compare nine ethnic groups. Multivariate logistic regression analyses, adjusting for the effects of age, gender, and socioeconomic status, yielded significant odds ratios using the Anglo groups as the reference, for suicidal ideation for the Mexican (OR = 1.76, p < .001), Pakistani (OR = 2.0, p < .01), and Vietnamese (OR = 1.48, p < .05) American groups. For thoughts about suicide in the past 2 weeks, only Pakistani and Mixed Ancestry youths had elevated risk. For suicidal plans in the past 2 weeks, Mixed Ancestry youths (OR = 2.02, p < .05) and Pakistani youths (OR = 3.20, p < .01) had elevated risk. For recent attempts, only the Pakistani American youths had elevated risk (OR = 3.19, p < .01). Future research needs to address whether these results hold in other ethnically diverse communities and, if so, what factors contribute to increased risk among some minority youth and not others.

Adolescent↗

Retest stability of DSM-III-R diagnoses among adolescents using the Diagnostic Interview Schedule for Children (DISC-2.1C).

Retest stability of DSM-III-R diagnoses was assessed using the DISC-2.1C with a sample of Anglo, African, and Hispanic American adolescent patients 12 to 17 years of age. Based on the kappa statistic, retest stability was fair for any disorder (kappa = .50), for any anxiety disorder (kappa = .44), for any affective disorder (kappa = .53), for any disruptive behavior disorder (kappa = .58), and for substance use disorders (kappa = .46). Although there was a trend for reliability to be somewhat higher for African Americans (kappa = .58) than for Anglos (kappa = .42) or Hispanics (kappa = .49), these differences were not statistically significant. In general, 15- to 17-year-olds had somewhat better reliability (kappa = .58) than did 12- to 14-year-olds (kappa = .44). Males had somewhat higher reliability (kappa = .63) than females (kappa = .43). These findings are congruent with those reported recently using the DISC-R (Schwab-Stone et al., 1993) and suggest that the DISC appears to be at least as reliable as other available child diagnostic instruments. In view of the fair-to-moderate levels of reliability of these instruments in general, future research should focus on the joint effects of instrument, subject, interviewer, and nomenclature on operating characteristics of diagnostic interview schedules, focusing in particular on factors affecting accurate recall and reporting of symptoms and episodes.

Adolescent↗