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John Myers

Publications and source records attributed to John Myers.

14 recordsLinked to original sources
PubMed2007

The heritability of cluster A personality disorders assessed by both personal interview and questionnaire.

BACKGROUND: Personality disorders (PDs) as assessed by questionnaires and personal interviews are heritable. However, we know neither how much unreliability of measurement impacts on heritability estimates nor whether the genetic and environmental risk factors assessed by these two methods are the same. We wish to know whether the same set of PD vulnerability factors are assessed by these two methods. METHOD: A total of 3334 young adult twin pairs from the Norwegian Institute of Public Health Twin Panel (NIPHTP) completed a questionnaire containing 91 PD items. One to 6 years later, 1386 of these pairs were interviewed with the Structured Interview for DSM-IV Personality (SIDP-IV). Self-report items predicting interview results were selected by regression. Measurement models were fitted using Mx. RESULTS: In the best-fit models, the latent liabilities to paranoid personality disorder (PPD), schizoid personality disorder (SPD) and schizotypal personality disorder (STPD) were all highly heritable with no evidence of shared environmental effects. For PPD and STPD, only unique environmental effects were specific to the interview measure whereas both environmental and genetic effects were found to be specific to the questionnaire assessment. For SPD, the best-fit model contained genetic and environmental effects specific to both forms of assessment. CONCLUSIONS: The latent liabilities to the cluster A PDs are highly heritable but are assessed by current methods with only moderate reliability. The personal interviews assessed the genetic risk for the latent trait with excellent specificity for PPD and STPD and good specificity for SPD. However, for all three PDs, the questionnaires were less specific, also indexing an independent set of genetic risk factors.

Adult↗
PubMed2006

Caffeine intake, toxicity and dependence and lifetime risk for psychiatric and substance use disorders: an epidemiologic and co-twin control analysis.

BACKGROUND: Although caffeine is the most commonly used psychoactive substance and often produces symptoms of toxicity and dependence, little is known, especially in community samples, about the association between caffeine use, toxicity and dependence and risk for common psychiatric and substance use disorders. METHOD: Assessments of lifetime maximal caffeine use and symptoms of caffeine toxicity and dependence were available on over 3600 adult twins ascertained from the population-based Virginia Twin Registry. Lifetime histories of major depression (MD), generalized anxiety disorder (GAD) and panic disorder, alcohol dependence, adult antisocial behavior and cannabis and cocaine abuse/dependence were obtained at personal interview. Logistic regression analyses in the entire sample and within monozygotic (MZ) twin pairs were conducted in SAS. RESULTS: In the entire sample, measures of maximal caffeine use, heavy caffeine use, and caffeine-related toxicity and dependence were significantly and positively associated with all seven psychiatric and substance use disorders. However, within MZ twin pairs, controlling for genetic and family environmental factors, these associations, while positive, were all non-significant. These results were similar when excluding twins who denied regular caffeine use. CONCLUSIONS: Maximal lifetime caffeine intake and caffeine-associated toxicity and dependence are moderately associated with risk for a wide range of psychiatric and substance use disorders. Analyses of these relationships within MZ twin pairs suggest that most of the observed associations are not causal. Rather, familial factors, which are probably in part genetic, predispose to both caffeine intake, toxicity and dependence and the risk for a broad array of internalizing and externalizing disorders.

Adult↗
PubMed2006

Economic analysis in hand surgery.

Economic analysis is a method for allocating resources among competing alternatives. Four techniques commonly used in an economic analysis are cost-minimization analysis, cost-effectiveness analysis, cost-benefit analysis, and cost-utility analysis. These analyses provide information to guide medical decisions and to set funding priorities. Understanding the differences between the techniques allows for better decision making. Although economic analysis is used widely in other fields of medicine, its use in studies of disorders of the hand has been sparse. Only recently has economic analysis been included in studies focused on the care of the upper-extremity patient. As such, to interpret the results of these studies better, hand surgeons need to understand the similarities and differences and the strengths and weaknesses of the different techniques. Such an understanding will allow hand surgeons to know when economic analyses are comparable. Furthermore it will aid them in providing their patients not only medically sound care, but also economically efficient care. This article provides a synopsis of the most widely used and accepted techniques for performing an economic analysis. The key concepts of each of the 4 techniques are shown by using the small number of studies that are available in the upper-extremity literature.

Costs and Cost Analysis↗
PubMed2006

Nonfatal all-terrain vehicle-related injuries to youths living on farms in the United States, 2001.

CONTEXT: Use of all-terrain vehicles (ATVs) in agriculture appears to be growing. PURPOSE: To provide estimates of ATV ownership and exposure on US farms and an overview of injuries to youths as a result of ATV use on the farm in 2001. METHODS: Analysis of the National Institute for Occupational Safety and Health and US Department of Agriculture 2001 Childhood Agricultural Injury Survey. These data, collected via telephone surveys, provide information on nonfatal injuries that occurred to youths younger than 20 years living on US farms during 2001. The injuries included both occupational and nonoccupational incidents. FINDINGS: Of an estimated 1.1 million youths living on farms, 36% had operated an ATV in 2001. Youths younger than 16 years were more likely to have operated an ATV than a tractor on these farms. An estimated 2,246 nonfatal ATV-related injuries occurred to youths younger than 20 years on US farms during 2001. The majority of these ATV injuries (1,668, 74%) occurred to youths identified as members of the household. Males accounted for 1,145 (69%) of the ATV injuries to household youths. The majority of the injuries were to youths aged 10-15 years (1,170, 70%). Most ATV injuries were the result of recreational activities (970, 58%). In addition, many of these injury events involved youths riding without helmets and using ATVs that were larger than the recommended size for their age.

Accidents, Traffic↗
PubMed2005

Percutaneous tracheostomy: one center's experience with a new modality.

BACKGROUND: A retrospective review of our experience with percutaneous tracheostomy was performed to determine our complication rate and pattern of use since this modality was introduced at our institution. METHODS: A retrospective chart review captured all patients in whom tracheostomy was performed or supervised by a trauma/critical care faculty member. Dates of hospital admission, ICU admission, intubation, discontinuation of mechanical ventilation, type and location of procedure, procedural complications, Injury Severity Score, charges, and patient demographics were collected. Percutaneous tracheostomy (PT) and open tracheostomy (OT) experiences were compared. RESULTS: Three hundred sixty-eight tracheostomies were performed (190 OT and 178 PT). The average time to tracheostomy (TTT) for PT patients decreased from 12.7 to 7.4 days. The average TTT for OT patients remained stable at 14.0 days. The complication rate was 3.5%, with 4 complications (1.5%) associated with OT and 9 complications (5.1%) associated with PT. All complications in the PT group occurred before using a single dilator system. The 9 complications in the PT group occurred among 5 surgeons, all before their 11th attempt. PT saves 444 dollars in charges per procedure. CONCLUSION: OT continues to be a safe method of performing tracheostomies. PT has a steep learning curve but can be mastered quickly. Benefits include a shorter time to tracheostomy, elimination of patient transport, and saving in charges. Initial PT attempts should be supervised by an experienced surgeon.

Female↗
PubMed2005

Understanding medical decision making in hand surgery.

The practice of medicine takes place in an environment of uncertainty. Expected value decision making, prospect theory, and regret theory are three theories of decision making under uncertainty that may be used to help us learn how patients and physicians make decisions. These theories form the underpinnings of decision analysis and provide the opportunity to introduce the broad discipline of decision science. Because decision analysis and economic analysis are underrepresented in upper extremity surgery, the authors believe these are important areas for future research.

Decision Making↗
PubMed2005

Sex differences in the relationship between social support and risk for major depression: a longitudinal study of opposite-sex twin pairs.

OBJECTIVE: Compared to men, women have larger and more intimate social networks and higher rates of major depression. Prior studies have suggested that women are more sensitive to the depressogenic effects of low social support, but most of these studies had substantial methodologic limitations. METHOD: In two interview waves at least 1 year apart, 1,057 pairs of opposite-sex dizygotic twin pairs ascertained from a population-based register were assessed. The authors predicted risk of major depression in the year before the wave 2 interview from levels of social support assessed at wave 1. RESULTS: Women reported higher levels of global social support than their twin brothers. Global social support at wave 1 predicted risk for major depression at wave 2 significantly more strongly in female than in male members of these pairs, and the same effect was seen when the analysis controlled for the history of major depression in the year prior to wave 1. Women were more sensitive than men to the depressogenic effects of low levels of social support, particularly from the co-twin, other relatives, parents, and spouses. Levels of social support did not explain the sex difference in risk for major depression. CONCLUSIONS: Emotionally supportive social relationships are substantially more protective against major depression for women than for men. While these effects cannot explain sex effects on the prevalence of major depression, they do suggest important sex differences in pathways of risk. Clarification of the nature of the causal links between low social support and depression in women is needed.

Adult↗
PubMed2004

Blunt splenic injuries: high nonoperative management rate can be achieved with selective embolization.

BACKGROUND: This retrospective review tests the hypothesis that including selective splenic arteriography and embolization in the algorithm of a previously existing nonoperative management (NOM) strategy will result in higher rates of successful NOM in patients with blunt splenic injury. METHODS: All patients with blunt splenic injuries documented by computed tomographic scan and/or operative findings over a 24-month period at a Level I trauma center were reviewed. A previously published series from this institution of 251 patients with splenic injury (Group 1) was then compared with the patients that constitute this current review (Group 2). Group 2 was then compared with patients described in a previous publication advocating nonselective arteriography in blunt splenic injuries. RESULTS: Thirteen patients with blunt splenic injury in Group 2 underwent 14 splenic embolization procedures, with 12 (93%) being successfully treated without operation. Group 2 had a significantly higher NOM rate (82% vs. 65%, p < 0.01) than Group 1. These results are similar to the series published by Sclafani et al. (82.1% vs. 83.1%) in which every patient with splenic injury that was managed non-operatively underwent arteriography with or without embolization. CONCLUSION: A high rate of NOM can be achieved with observation and selective use of arteriography with or without embolization in the management of blunt splenic injuries.

Algorithms↗
PubMed2003

The structure of genetic and environmental risk factors for common psychiatric and substance use disorders in men and women.

BACKGROUND: Patterns of comorbidity suggest that the common psychiatric and substance use syndromes may be divisible into 2 broad groups of internalizing and externalizing disorders. We do not know how genetic and environmental risk factors contribute to this pattern of comorbidity or whether the etiologic structure of these groups differ in men and women. METHODS: Lifetime diagnoses for 10 psychiatric syndromes were obtained at a personal interview in more than 5600 members of male-male and female-female twin pairs ascertained from a population-based registry. Multivariate twin modeling was performed using the program Mx. RESULTS: We first fit models to the following 7 syndromes: major depression, generalized anxiety disorder, phobia, alcohol dependence, drug abuse/dependence, adult antisocial behavior, and conduct disorder. The full model, which could be constrained to equality in male and female subjects, identified 2 genetic factors. The first had strongest loadings on alcohol dependence, drug abuse/dependence, adult antisocial behavior, and conduct disorder; the second, on major depression, generalized anxiety disorder, and phobia. Alcohol dependence and drug abuse/dependence had substantial disorder-specific genetic risk factors. Shared environmental factors were most pronounced for conduct disorder and adult antisocial behavior. No clear internalizing/externalizing structure was seen for the unique environmental common factors. We then fit models to 5 internalizing syndromes. The full model, which could also be constrained to equality in men and women, revealed one genetic factor loading most heavily on major depression and generalized anxiety disorder and another loading most strongly on animal and situational phobia. CONCLUSIONS: The underlying structure of the genetic and environmental risk factors for the common psychiatric and drug abuse disorders in men and women is very similar. Genetic risk factors predispose to 2 broad groups of internalizing and externalizing disorders. Within the internalizing disorders, 2 genetic factors are seen that predispose to disorders dominated by anxious-misery and fear. Substance use disorders have disorder-specific genetic risks. The externalizing disorders of conduct disorder and adult antisocial behavior are significantly influenced by the shared environment. The pattern of lifetime comorbidity of common psychiatric and substance use disorders results largely from the effects of genetic risk factors.

Adult↗
PubMed2003

Protocol-driven nonoperative management in patients with blunt splenic trauma and minimal associated injury decreases length of stay.

BACKGROUND: The purpose of this study was to analyze the impact of more selective use of admission angiography combined with protocolized nonoperative management for blunt splenic injury. METHODS: This was a retrospective chart review of all patients with splenic injuries and Injury Severity Score < 20 managed by protocol and comparison with a prior matched group managed with admission angiography. RESULTS: Forty-three patients were managed under the protocol, with 22 patients treated with admission angiography and the remainder undergoing observation only. Nonoperative salvage was 100% in this group, with a length of stay of 3.3 days. The matched, nonprotocol group had a nonoperative salvage rate of 95%, with a length of stay of 6.8 days. CONCLUSION: Protocol-driven management of splenic injury using admission angiography selectively for higher grade splenic injuries led to a decreased length of stay, higher therapeutic yield, and decreased use of hospital resources without any increase in the failure rate of nonoperative management in a selected group of patients with isolated splenic injuries.

Adult↗
PubMed2002

The etiology of phobias: an evaluation of the stress-diathesis model.

BACKGROUND: We evaluated for phobias the prediction of the stress-diathesis model that the magnitude of stress at onset is inversely proportional to the level of underlying diathesis. METHODS: In more than 7500 twins from a population-based registry, we assessed the personality trait of neuroticism--as an index of phobia-proneness--and the lifetime histories of 5 phobia subtypes (agoraphobia, social, animal, situational, and blood or injury) and their associated irrational fears. Interviewers classified the mode of acquisition of the fear in phobic twins into 5 possible categories: trauma to self (further divided by severity), observed trauma to others, observed fear in others, taught by others to be afraid, and no memory of how or why fear developed. Analyses were conducted by logistic regression and analysis of covariance. RESULTS: The mode of acquisition had moderate test-retest reliability and differed meaningfully across phobia subtypes. None of the 3 tests of the stress-diathesis model was confirmatory: (1) the risk of phobias was not elevated in co-twins of twins who had no memory of their mode of acquisition, (2) the risk of phobias was not decreased in co-twins of twins who had severe trauma to self, and (3) no significant relationship, in phobic twins, was found between levels of neuroticism and mode of acquisition. CONCLUSIONS: These results are inconsistent with the traditional etiologic theories for phobias, which assume conditioning or social transmission. However, they are compatible with nonassociative models, which postulate that the vulnerability to phobias is largely innate and does not arise directly from environmental experiences. The stress-diathesis model may not be an appropriate paradigm for phobic disorders.

Adult↗