Association between chiropractic care and use of prescription opioids among older medicare beneficiaries with spinal pain: a retrospective observational study.

BACKGROUND: The burden of spinal pain can be aggravated by the hazards of opioid analgesics, which are still widely prescribed for spinal pain despite evidence-based clinical guidelines that identify non-pharmacological therapies as the preferred first-line approach. Previous studies have found that chiropractic care is associated with decreased use of opioids, but have not focused on older Medicare beneficiaries, a vulnerable population with high rates of co-morbidity and polypharmacy. The purpose of this investigation was to evaluate the association between chiropractic utilization and use of prescription opioids among older adults with spinal pain. METHODS: We conducted a retrospective observational study in which we examined a nationally representative multi-year sample of Medicare claims data, 2012-2016. The study sample included 55,949 Medicare beneficiaries diagnosed with spinal pain, of whom 9,356 were recipients of chiropractic care and 46,593 were non-recipients. We measured the adjusted risk of filling a prescription for an opioid analgesic for up to 365 days following diagnosis of spinal pain. Using Cox proportional hazards modeling and inverse weighted propensity scoring to account for selection bias, we compared recipients of both primary care and chiropractic to recipients of primary care alone regarding the risk of filling a prescription. RESULTS: The adjusted risk of filling an opioid prescription within 365 days of initial visit was 56% lower among recipients of chiropractic care as compared to non-recipients (hazard ratio 0.44; 95% confidence interval 0.40-0.49). CONCLUSIONS: Among older Medicare beneficiaries with spinal pain, use of chiropractic care is associated with significantly lower risk of filling an opioid prescription.

Efficiency of primary spine care as compared to conventional primary care: a retrospective observational study at an Academic Medical Center.

BACKGROUND: Primary Spine Care (PSC) is an innovative model for the primary management of patients with spine-related disorders (SRDs), with a focus on the use of non-pharmacological therapies which now constitute the recommended first-line approach to back pain. PSC clinicians serve as the initial or early point of contact for spine patients and utilize evidence-based spine care pathways to improve outcomes and reduce escalation of care (EoC; e.g., spinal injections, diagnostic imaging, hospitalizations, referrals to a specialist). The present study examined 6-month outcomes to evaluate the efficiency of care for patients who received PSC as compared to conventional primary care. We hypothesized that patients seen by a PSC clinician would have lower rates of EoC compared to patients who received usual care by a primary care (PC) clinician. METHODS: This was a retrospective observational study. We evaluated 6-month outcomes for two groups seen and treated for an SRD between February 01, 2017 and January 31, 2020. Patient groups were comprised of N = 1363 PSC patients (Group A) and N = 1329 PC patients (Group B). We conducted Pearson chi-square and logistic regression (adjusting for patient characteristics that were unbalanced between the two groups) to determine associations between the two groups and 6-month outcomes. RESULTS: Within six months of an initial visit for an SRD, a statistically significantly smaller proportion of PSC patients utilized healthcare resources for spine care as compared to the PC patients. When adjusting for patient characteristics, those who received care from the PSC clinician were less likely within 6 months of an initial visit to be hospitalized (OR = .47, 95% CI .23-.97), fill a prescription for an opioid analgesic (OR = .43; 95% CI .29-.65), receive a spinal injection (OR = .56, 95% CI .33-.95), or have a visit with a specialist (OR = .48, 95% CI .35-.67) as compared to those who received usual primary care. CONCLUSIONS: Patients who received PSC in an academic primary care clinic experienced significantly less escalation of their spine care within 6 months of their initial visit. The PSC model may offer a more efficient approach to the primary care of spine problems for patients with SRDs, as compared to usual primary care.

Initial Choice of Spinal Manipulation Reduces Escalation of Care for Chronic Low Back Pain Among Older Medicare Beneficiaries.

STUDY DESIGN: We combined elements of cohort and crossover-cohort design. OBJECTIVE: The objective of this study was to compare longterm outcomes for spinal manipulative therapy (SMT) and opioid analgesic therapy (OAT) regarding escalation of care for patients with chronic low back pain (cLBP). SUMMARY OF BACKGROUND DATA: Current evidence-based guidelines for clinical management of cLBP include both OAT and SMT. For long-term care of older adults, the efficiency and value of continuing either OAT or SMT are uncertain. METHODS: We examined Medicare claims data spanning a five-year period. We included older Medicare beneficiaries with an episode of cLBP beginning in 2013. All patients were continuously enrolled under Medicare Parts A, B, and D. We analyzed the cumulative frequency of encounters indicative of an escalation of care for cLBP, including hospitalizations, emergency department visits, advanced diagnostic imaging, specialist visits, lumbosacral surgery, interventional pain medicine techniques, and encounters for potential complications of cLBP. RESULTS: SMT was associated with lower rates of escalation of care as compared to OAT. The adjusted rate of escalated care encounters was approximately 2.5 times higher for initial choice of OAT vs. initial choice of SMT (with weighted propensity scoring: rate ratio 2.67, 95% confidence interval 2.64-2.69, P < .0001). CONCLUSION: Among older Medicare beneficiaries who initiated long-term care for cLBP with opioid analgesic therapy, the adjusted rate of escalated care encounters was significantly higher as compared to those who initiated care with spinal manipulative therapy.Level of Evidence: 3.

Long-Term Medicare Costs Associated With Opioid Analgesic Therapy vs Spinal Manipulative Therapy for Chronic Low Back Pain in a Cohort of Older Adults.

OBJECTIVES: The purpose of this study was to compare Medicare healthcare expenditures for patients who received long-term treatment of chronic low back pain (cLBP) with either opioid analgesic therapy (OAT) or spinal manipulative therapy (SMT). METHODS: We conducted a retrospective observational study using a cohort design for analysis of Medicare claims data. The study population included Medicare beneficiaries enrolled under Medicare Parts A, B, and D from 2012 through 2016. We assembled cohorts of patients who received long-term management of cLBP with OAT or SMT (such as delivered by chiropractic or osteopathic practitioners) and evaluated the comparative effect of OAT vs SMT upon expenditures, using multivariable regression to control for beneficiary characteristics and measures of health status, and propensity score weighting and binning to account for selection bias. RESULTS: The study sample totaled 28,160 participants, of whom 77% initiated long-term care of cLBP with OAT, and 23% initiated care with SMT. For care of low back pain specifically, average long-term costs for patients who initiated care with OAT were 58% lower than those who initiated care with SMT. However, overall long-term healthcare expenditures under Medicare were 1.87 times higher for patients who initiated care via OAT compared with those initiated care with SMT (95% CI 1.65-2.11; P < .0001). CONCLUSIONS: Adults aged 65 to 84 who initiated long-term treatment for cLBP via OAT incurred lower long-term costs for low back pain but higher long-term total healthcare costs under Medicare compared with patients who initiated long-term treatment with SMT.

Patient Characteristics Associated With Self-Reported Adherence to Chiropractic Treatment Recommendations: A Feasibility Study.

OBJECTIVE: The purpose of this study was to examine the feasibility of developing and administering a patient adherence survey to assess self-reported adherence to treatment recommendations from a chiropractic doctor within an academic health center. METHODS: The survey items were developed by the authors and vetted by the university's students and faculty, who serve as health care practitioners at an academic health center. Adult patients with spine pain who were seen by a doctor of chiropractic at an academic health center were included in this survey study. A 32-item survey was administered between October 2019 and March 2020. RESULTS: A total of 62 respondents completed the anonymous survey. We found that 89% of respondents adhered to their clinic appointments. Although 82% of respondents said that their doctor's recommendation made sense, only 44% reported completely following treatment recommendations for at-home stretching and exercise. CONCLUSION: This study determined that it is feasible to assess patient self-reported adherence to chiropractic treatment within an academic health center setting. In our sample we found that although patient adherence to clinic appointments was high, adherence to treatments was not.

Experiences and Attitudes About Chiropractic Care and Prescription Drug Therapy Among Patients With Back Pain: A Cross-Sectional Survey.

OBJECTIVE: The purpose of this study was to examine experiences and attitudes toward care offered by chiropractors and prescription drug therapy offered by medical physicians for patients who have back pain. METHODS: A cross-sectional survey measured patients with back pain (n = 150) seeking care within an academic primary care setting. A survey assessed patient experiences, beliefs, and attitudes regarding chiropractic care and prescription drug therapy. Two samples of patients in the New Hampshire region included 75 patients treated by a doctor of chiropractic (DC) and 75 treated by a medical primary care physician (PCP). The 30-item survey was sent to existing and new patients between February 2019 and January 2020. Between-group comparisons were examined to test rates of reporting and to determine the mean difference in the total number of office visits between the 2 samples. RESULTS: Patients treated by both DCs and PCPs reported high overall satisfaction with chiropractic care received for low back pain with no significant differences between groups. The majority in both groups reported that seeing a DC for back pain made sense to them (95% of patients treated by a DC and 75% of patients treated by a PCP) whereas the minority reported that taking prescription drugs for back pain made sense (25% of patients treated by a DC and 41% of patients treated by a PCP). There was no statistical difference between groups when patients were asked if seeing a chiropractor changed their beliefs or behaviors about taking pain medication. Significant differences were found between groups for agreement that chiropractic care would be a suitable treatment for back pain (79% of patients treated by a DC and 45% of patients treated by a PCP). There were 7% of patients treated by PCP and 23% of the patients treated by DC who agreed that a DC would be the first health care provider they would like to see for their general health needs. CONCLUSIONS: In this sample of patients, patient satisfaction regarding chiropractic care received for back pain was high. There were differences between patient groups about preferences for treatment for back pain. Our results indicate that patients reported that seeing a DC for back pain did not change their beliefs or behaviors regarding prescription drug therapy provided by their medical PCP.

Initial Choice of Spinal Manipulative Therapy for Treatment of Chronic Low Back Pain Leads to Reduced Long-term Risk of Adverse Drug Events Among Older Medicare Beneficiaries.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: Opioid Analgesic Therapy (OAT) and Spinal Manipulative Therapy (SMT) are evidence-based strategies for treatment of chronic low back pain (cLBP), but the long-term safety of these therapies is uncertain. The objective of this study was to compare OAT versus SMT with regard to risk of adverse drug events (ADEs) among older adults with cLBP. SUMMARY OF BACKGROUND DATA: We examined Medicare claims data spanning a 5-year period on fee-for-service beneficiaries aged 65 to 84 years, continuously enrolled under Medicare Parts A, B, and D for a 60-month study period, and with an episode of cLBP in 2013. We excluded patients with a diagnosis of cancer or use of hospice care. METHODS: All included patients received long-term management of cLBP with SMT or OAT. We assembled cohorts of patients who received SMT or OAT only, and cohorts of patients who crossed over from OAT to SMT or from SMT to OAT. We used Poisson regression to estimate the adjusted incidence rate ratio for outpatient ADE among patients who initially chose OAT as compared with SMT. RESULTS: With controlling for patient characteristics, health status, and propensity score, the adjusted rate of ADE was more than 42 times higher for initial choice of OAT versus initial choice of SMT (rate ratio 42.85, 95% CI 34.16-53.76, P < 0.0001). CONCLUSION: Among older Medicare beneficiaries who received long-term care for cLBP the adjusted rate of ADE for patients who initially chose OAT was substantially higher than those who initially chose SMT.Level of Evidence: 2.

Spinal Manipulation vs Prescription Drug Therapy for Chronic Low Back Pain: Beliefs, Satisfaction With Care, and Qualify of Life Among Older Medicare Beneficiaries.

OBJECTIVE: The objective of this study was to compare patients' perspectives on the use of spinal manipulative therapy (SMT) compared to prescription drug therapy (PDT) with regard to health-related quality of life (HRQoL), patient beliefs, and satisfaction with treatment. METHODS: Four cohorts of Medicare beneficiaries were assembled according to previous treatment received as evidenced in claims data: SMT, PDT, and 2 crossover cohorts (where participants experienced both types of treatments). A total of 195 Medicare beneficiaries responded to the survey. Outcome measures used were a 0-to-10 numeric rating scale to measure satisfaction, the Low Back Pain Treatment Beliefs Questionnaire to measure patient beliefs, and the 12-item Short Form Health Survey to measure HRQoL. RESULTS: Recipients of SMT were more likely to be very satisfied with their care (84%) than recipients of PDT (50%; P = .002). The SMT cohort self-reported significantly higher HRQoL compared to the PDT cohort; mean differences in physical and mental health scores on the 12-item Short Form Health Survey were 12.85 and 9.92, respectively. The SMT cohort had a lower degree of concern regarding chiropractic care for their back pain compared to the PDT cohort's reported concern about PDT (P = .03). CONCLUSION: Among older Medicare beneficiaries with chronic low back pain, long-term recipients of SMT had higher self-reported rates of HRQoL and greater satisfaction with their modality of care than long-term recipients of PDT. Participants who had longer-term management of care were more likely to have positive attitudes and beliefs toward the mode of care they received.

Cost comparison of two approaches to chiropractic care for patients with acute and sub-acute low Back pain care episodes: a cohort study.

BACKGROUND: Low back pain (LBP) imposes a costly burden upon patients, healthcare insurers, and society overall. Spinal manipulation as practiced by chiropractors has been found be cost-effective for treatment of LBP, but there is wide variation among chiropractors in their approach to clinical care, and the most cost-effective approach to chiropractic care is uncertain. To date, little has been published regarding the cost effectiveness of different approaches to chiropractic care. Thus, the current study presents a cost comparison between chiropractic approaches for patients with acute or subacute care episodes for low back pain. METHODS: We employed a retrospective cohort design to examine costs of chiropractic care among patients diagnosed with acute or subacute low back pain. The study time period ranged between 07/01/2016 and 12/22/2017. We compared cost outcomes for patients of two cohorts of chiropractors within health care system: Cohort 1) a general network of providers, and Cohort 2) a network providing conservative evidence-based care for rapid resolution of pain. We used generalized linear regression modeling to estimate the comparative influence of demographic and clinical factors on expenditures. RESULTS: A total of 25,621 unique patients were included in the analyses. The average cost per patient for Cohort 2 (mean allowed amount $252) was lower compared to Cohort 1 (mean allowed amount $326; 0.77, 95% CI 0.75-0.79, p < .001). Patient and clinician related factors such as health plan, provider region, and sex also significantly influenced costs. CONCLUSIONS: This study comprehensively analyzed cost data associated with the chiropractic care of adults with acute or sub-acute low back pain cared by two cohorts of chiropractic physicians. In general, providers in Cohort 2 were found to be significantly associated with lower costs for patient care as compared to Cohort 1. Utilization of a clinical model characterized by a patient-centered clinic approach and standardized, best-practice clinical protocols may offer lower cost when compared to non-standardized clinical approaches to chiropractic care.

Implementation of the Primary Spine Care Model in a Multi-Clinician Primary Care Setting: An Observational Cohort Study.

OBJECTIVE: The objective of this investigation was to compare the value of primary spine care (PSC) with usual care for management of patients with spine-related disorders (SRDs) within a primary care setting. METHODS: We retrospectively examined existing patient encounter data at 3 primary care sites within a multi-clinic health system. Designated clinicians serve in the role as PSC as the initial point of contact for spine patients, coordinate, and follow up for the duration of the episode of care. A PSC may be a chiropractor, physical therapist, or medical or osteopathic physician who has been trained to provide primary care for patients with SRDs. The PSC model of care had been introduced at site I (Lebanon, New Hampshire); sites II (Bedford, New Hampshire) and III (Nashua, New Hampshire) served as control sites where patients received usual care. To evaluate cost outcomes, we employed a controlled quasi-experimental design for analysis of health claims data. For analysis of clinical outcomes, we compared clinical records for PSC at site I and usual care at sites II and III, all with reference to usual care at site I. We examined clinical encounters occurring over a 24-month period, from February 1, 2016 through January 31, 2018. RESULTS: Primary spine care was associated with reduced total expenditures compared with usual care for SRDs. At site I, average per-patient expenditure was $162 in year 1 and $186 in year 2, compared with site II ($332 in year 1; $306 in year 2) and site III ($467 in year 1; $323 in year 2). CONCLUSION: Among patients with SRDs included in this study, implementation of the PSC model within a conventional primary care setting was associated with a trend toward reduced total expenditures for spine care compared with usual primary care. Implementation of PSC may lead to reduced costs and resource utilization, but may be no more effective than usual care regarding clinical outcomes.

Trends in Insurance Coverage for Complementary Health Care Services.

Introduction: Complementary health care professionals deliver a substantial component of clinical services in the United States, but insurance coverage for many such services may be inadequate. The objective of this project was to follow up on an earlier single-year study with an evaluation of trends in reimbursement for complementary health care services over a 7-year period. Methods: The authors employed a retrospective serial cross-sectional design to analyze health insurance claims for services provided by licensed acupuncturists, chiropractors, and naturopaths in New Hampshire (NH) from 2011 to 2017. They restricted the analyses to claims in nonemergent outpatient settings for Current Procedural Terminology code 99213, which is one of the most commonly used clinical procedure codes across all specialties. They evaluated by year the likelihood of reimbursement, as compared with primary care physicians as the gold standard. A generalized estimating equation model was used to account for within-person correlations among the separate claim reimbursement indicators for individuals used in the analysis, using an exchangeable working covariance structure among claims for the same individual. Reimbursement was defined as payment >0 dollars. Results: The total number of clinical services claimed was 26,725 for acupuncture, 8317 for naturopathic medicine, 2,539,144 for chiropractic, and 1,860,271 for primary care. Initially, likelihood of reimbursement for naturopathic physicians was higher relative to primary care physicians, but was lower from 2014 onward. Odds of reimbursement for both acupuncture and chiropractic claims remained lower throughout the study period. In 2017, as compared with primary care the likelihood of reimbursement was 77% lower for acupuncturists, 72% lower for chiropractors, and 64% lower for naturopaths. Conclusion: The likelihood of reimbursement for complementary health care services is significantly lower than that for primary care physicians in NH. Lack of insurance coverage may result in reduced patient access to such services.

Impact of Chiropractic Care on Use of Prescription Opioids in Patients with Spinal Pain.

OBJECTIVE: Utilization of nonpharmacological pain management may prevent unnecessary use of opioids. Our objective was to evaluate the impact of chiropractic utilization upon use of prescription opioids among patients with spinal pain. DESIGN AND SETTING: We employed a retrospective cohort design for analysis of health claims data from three contiguous states for the years 2012-2017. SUBJECTS: We included adults aged 18-84 years enrolled in a health plan and with office visits to a primary care physician or chiropractor for spinal pain. We identified two cohorts of subjects: Recipients received both primary care and chiropractic care, and nonrecipients received primary care but not chiropractic care. METHODS: We performed adjusted time-to-event analyses to compare recipients and nonrecipients with regard to the risk of filling an opioid prescription. We stratified the recipient populations as: acute (first chiropractic encounter within 30 days of diagnosis) and nonacute (all other patients). RESULTS: The total number of subjects was 101,221. Overall, between 1.55 and 2.03 times more nonrecipients filled an opioid prescription, as compared with recipients (in Connecticut: hazard ratio [HR] = 1.55, 95% confidence interval [CI] = 1.11-2.17, P = 0.010; in New Hampshire: HR = 2.03, 95% CI = 1.92-2.14, P < 0.0001). Similar differences were observed for the acute groups. CONCLUSIONS: Patients with spinal pain who saw a chiropractor had half the risk of filling an opioid prescription. Among those who saw a chiropractor within 30 days of diagnosis, the reduction in risk was greater as compared with those with their first visit after the acute phase.

Unmasking the Association between Psychopathic Traits and Adaptive Functioning in Children.

The appearance of positive adjustment is a theoretically relevant element of psychopathy, and is valuable for demonstrating its incremental validity over a broader antisocial orientation. We examined associations between psychopathic-like features and two measures of adaptive functioning: psychometric intelligence and (immunity to) internalizing problems. Ratings of psychopathy and behavioral problems were obtained in a community sample of children (N=1210). A bifactor model was fit to the psychopathic personality items to capture the underlying variance common to all traits (i.e., general factor) and to isolate a unique cluster of interpersonal traits. We hypothesized that the general psychopathy factor and specific interpersonal factor would exhibit opposing patterns of associations with external criteria. As expected, the general psychopathy factor was associated with greater anxiety/depression and lower cognitive ability. Contrary to hypothesis, the interpersonal factor was not associated with adaptive functioning (i.e., reduced internal distress or superior cognitive ability), although the predicted relations emerged after controlling for antisocial behavior. Hence, in a large representative sample of children, there is limited support for the premise that psychopathic traits are associated with positive adjustment and enhanced intelligence. Implications regarding the construct validity of psychopathy are discussed, including the role of heterogeneity in sample characteristics and instrument.

Resilience in the United States Air Force: Psychometric properties of the Connor-Davidson Resilience Scale (CD-RISC).

Results are presented for the largest study (N = 53,692) ever conducted on the 25-item Connor-Davidson Resilience Scale (CD-RISC), a popular measure of resilience. We examined the internal consistency of the CD-RISC items and associated mean resilience levels within a sample of enlisted basic trainees in the United States Air Force. In addition, the predictive validity of the CD-RISC Total Score was examined for real-life military outcomes, including attrition from service and mental health diagnosis. The CD-RISC items demonstrated strong internal consistency. Item-level examinations of scores revealed that most trainees reported relatively high resilience. Results indicated that resilience measured at the beginning of military service is a significant predictor of (a) attrition from service and (b) obtaining a mental health diagnosis within 6 months of entry. Implications and future directions are discussed. (PsycINFO Database Record

Psychopathic personality development from ages 9 to 18: Genes and environment.

The genetic and environmental etiology of individual differences was examined in initial level and change in psychopathic personality from ages 9 to 18 years. A piecewise growth curve model, in which the first change score (G1) influenced all ages (9-10, 11-13, 14-15, and 16-18 years) and the second change score (G2) only influenced ages 14-15 and 16-18 years, fit the data better did than the standard single slope model, suggesting a turning point from childhood to adolescence. The results indicated that variations in levels and both change scores were mainly due to genetic (A) and nonshared environmental (E) influences (i.e., AE structure for G0, G1, and G2). No sex differences were found except on the mean values of level and change scores. Based on caregiver ratings, about 81% of variance in G0, 89% of variance in G1, and 94% of variance in G2 were explained by genetic factors, whereas for youth self-reports, these three proportions were 94%, 71%, and 66%, respectively. The larger contribution of genetic variance and covariance in caregiver ratings than in youth self-reports may suggest that caregivers considered the changes in their children to be more similar as compared to how the children viewed themselves.

Motor impulsivity during childhood and adolescence: a longitudinal biometric analysis of the go/no-go task in 9- to 18-year-old twins.

In the present study, we investigated genetic and environmental effects on motor impulsivity from childhood to late adolescence using a longitudinal sample of twins from ages 9 to 18 years. Motor impulsivity was assessed using errors of commission (no-go errors) in a visual go/no-go task at 4 time points: ages 9-10, 11-13, 14-15, and 16-18 years. Significant genetic and nonshared environmental effects on motor impulsivity were found at each of the 4 waves of assessment with genetic factors explaining 22%-41% of the variance within each of the 4 waves. Phenotypically, children's average performance improved across age (i.e., fewer no-go errors during later assessments). Multivariate biometric analyses revealed that common genetic factors influenced 12%-40% of the variance in motor impulsivity across development, whereas nonshared environmental factors common to all time points contributed to 2%-52% of the variance. Nonshared environmental influences specific to each time point also significantly influenced motor impulsivity. Overall, results demonstrated that although genetic factors were critical to motor impulsivity across development, both common and specific nonshared environmental factors played a strong role in the development of motor impulsivity across age. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

The heritability of psychopathic personality in 14- to 15-year-old twins: a multirater, multimeasure approach.

Until now, no study has examined the genetic and environmental influences on psychopathic personality across different raters and method of assessment. Participants were part of a community sample of male and female twins born between 1990 and 1995. The Child Psychopathy Scale and the Antisocial Process Screening Device were administered to the twins and their parents when the twins were 14-15 years old. The Psychopathy Checklist: Youth Version (PCL:YV) was administered and scored by trained testers. Results showed that a 1-factor common pathway model was the best fit for the data. Genetic influences explained 69% of the variance in the latent psychopathic personality factor, while nonshared environmental influences explained 31%. Measurement-specific genetic effects accounted for between 9% and 35% of the total variance in each of the measures, except for PCL:YV, where all genetic influences were in common with the other measures. Measure-specific nonshared environmental influences were found for all measures, explaining between 17% and 56% of the variance. These findings provide further evidence of the heritability in psychopathic personality among adolescents, although these effects vary across the ways in which these traits are measured, in terms of both informant and instrument used.

Psychopathic Personality and Negative Parent-to-Child Affect: A Longitudinal Cross-lag Twin Study.

PURPOSE: Previous studies that have explored the relationship between parenting style and children's antisocial behavior have generally found significant bidirectional effects, whereby parenting behaviors influence their child's antisocial outcomes, but a child's behaviors also lead to changes in parenting style. METHODS: The present study investigated the genetic and environmental underpinnings of the longitudinal relationship between negative parent-to-child affect and psychopathic personality in a sample of 1,562 twins. Using a biometrical cross-lag analysis, bidirectional effects were investigated across two waves of assessment when the twins were ages 9-10 and 14-15, utilizing both caregiver and youth self-reports. RESULTS: Results demonstrated that negative parental affects observed at ages 9-10 influenced the child's later psychopathic personality at ages 14-15, based on both caregiver and youth self-reports. For these 'parent-driven effects', both genetic and non-shared environmental factors were important in the development of later psychopathic personality during adolescence. There were additional 'child-driven effects' such that children's psychopathic personality at ages 9-10 influenced negative parent-to-child affect at ages 14-15, but only within caregiver reports. CONCLUSIONS: Thus, children's genetically influenced psychopathic personality seemed to evoke parental negativity at ages 14-15, highlighting the importance of investigating bidirectional effects in parent-child relationships to understand the development of these traits.

The Southern California Twin Register at the University of Southern California: III.

The Southern California Twin Register at the University of Southern California (USC) was initiated in 1984 and continues to provide an important resource for studies investigating genetic and environmental influences on human behavior. This article provides an update on the current register and its potential for future twin studies using recruitment through school district databases and voter records. An overview is also provided for an ongoing longitudinal twin study investigating the development of externalizing psychopathology from childhood to young adulthood, the USC Study of Risk Factors for Antisocial Behavior. Characteristics of the twins and their families are presented, including recruitment and participation rates, as well as attrition analyses and a summary of key findings to date.

Genetic and environmental influences on impulsivity: a meta-analysis of twin, family and adoption studies.

A meta-analysis of twin, family and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on impulsivity. The best fitting model for 41 key studies (58 independent samples from 14 month old infants to adults; N=27,147) included equal proportions of variance due to genetic (0.50) and non-shared environmental (0.50) influences, with genetic effects being both additive (0.38) and non-additive (0.12). Shared environmental effects were unimportant in explaining individual differences in impulsivity. Age, sex, and study design (twin vs. adoption) were all significant moderators of the magnitude of genetic and environmental influences on impulsivity. The relative contribution of genetic effects (broad sense heritability) and unique environmental effects were also found to be important throughout development from childhood to adulthood. Total genetic effects were found to be important for all ages, but appeared to be strongest in children. Analyses also demonstrated that genetic effects appeared to be stronger in males than in females. Method of assessment (laboratory tasks vs. questionnaires), however, was not a significant moderator of the genetic and environmental influences on impulsivity. These results provide a structured synthesis of existing behavior genetic studies on impulsivity by providing a clearer understanding of the relative genetic and environmental contributions in impulsive traits through various stages of development.