Within-individual Models Research Articles

Physical activity and depression during the COVID-19 pandemic in Australia: A twin study

Background and aimsLow levels of physical activity (PA) have been associated with depression. However, shared familial (genetic and environmental) factors might confound this association, given PA and depression tend to cluster in families. We investigated the association between levels of PA and depression symptoms during the COVID-19 pandemic, and then controlled for shared familial factors by design, and assessed if being in lockdown modified this association. MethodsWe applied within-individual and within-pair regression models to questionnaire data from adult same-sex twin pair members of Twins Research Australia collected between August and November 2020. Depression score was measured using the Depression, Anxiety and Stress Scale (DASS-21), and PA levels and changes since the onset of the pandemic were self-reported. Adjusted models included body-mass-index, sleep adequacy, smoking, and alcohol consumption. ResultsThe sample of 1148 twins was predominantly female (80%) and had a mean age of 52.5 (Standard Deviation = 15.7). Reduced PA was associated with higher depression scores (β = 1.22, 95% Confidence Interval: 0.70–1.73, P < 0.001) in the adjusted within-individual model, but evidence of a within-pair association was weak. Lockdown status was an effect modifier (P = 0.006); relative to the co-twin, increased PA was associated with lower depression scores for those not in lockdown but higher scores for those in lockdown. ConclusionShared familial factors play a role in the association between PA and depression. Health interventions and educational campaigns for families rather than just individuals might be better suited to improve mental health outcomes, especially when opportunities for PA and exercise are limited.

Unequal and Unsupportive: Exposure to Poor People Weakens Support for Redistribution among the Rich

Abstract Do the rich become more or less supportive of redistribution when exposed to poor people in their local surroundings? Most existing observational studies find that exposure to poor individuals is positively associated with support for redistribution among the well-off, but one prominent field experiment found a negative link. We seek to resolve these divergent findings by employing a design closer to the studies that have found a positive link, but with more causal leverage than these; specifically, a three-wave panel survey linked with fine-grained registry data on local income composition in Denmark. In within-individual models, increased exposure to poor individuals is associated with lower support for redistribution among wealthy individuals. By contrast, between-individual models yield a positive relationship, thus indicating that self-selection based on stable individual characteristics likely explains the predominant finding in previous work.

Associations between β-blockers and psychiatric and behavioural outcomes: A population-based cohort study of 1.4 million individuals in Sweden.

β-blockers are widely used for treating cardiac conditions and are suggested for the treatment of anxiety and aggression, although research is conflicting and limited by methodological problems. In addition, β-blockers have been associated with precipitating other psychiatric disorders and suicidal behaviour, but findings are mixed. We aimed to examine associations between β-blockers and psychiatric and behavioural outcomes in a large population-based cohort in Sweden. We conducted a population-based longitudinal cohort study using Swedish nationwide high-quality healthcare, mortality, and crime registers. We included 1,400,766 individuals aged 15 years or older who had collected β-blocker prescriptions and followed them for 8 years between 2006 and 2013. We linked register data on dispensed β-blocker prescriptions with main outcomes, hospitalisations for psychiatric disorders (not including self-injurious behaviour or suicide attempts), suicidal behaviour (including deaths from suicide), and charges of violent crime. We applied within-individual Cox proportional hazards regression to compare periods on treatment with periods off treatment within each individual in order to reduce possible confounding by indication, as this model inherently adjusts for all stable confounders (e.g., genetics and health history). We also adjusted for age as a time-varying covariate. In further analyses, we adjusted by stated indications, prevalent users, cardiac severity, psychiatric and crime history, individual β-blockers, β-blocker selectivity and solubility, and use of other medications. In the cohort, 86.8% (n = 1,215,247) were 50 years and over, and 52.2% (n = 731,322) were women. During the study period, 6.9% (n = 96,801) of the β-blocker users were hospitalised for a psychiatric disorder, 0.7% (n = 9,960) presented with suicidal behaviour, and 0.7% (n = 9,405) were charged with a violent crime. There was heterogeneity in the direction of results; within-individual analyses showed that periods of β-blocker treatment were associated with reduced hazards of psychiatric hospitalisations (hazard ratio [HR]: 0.92, 95% confidence interval [CI]: 0.91 to 0.93, p < 0.001), charges of violent crime (HR: 0.87, 95% CI: 0.81 to 0.93, p < 0.001), and increased hazards of suicidal behaviour (HR: 1.08, 95% CI: 1.02 to 1.15, p = 0.012). After stratifying by diagnosis, reduced associations with psychiatric hospitalisations during β-blocker treatment were mainly driven by lower hospitalisation rates due to depressive (HR: 0.92, 95% CI: 0.89 to 0.96, p < 0.001) and psychotic disorders (HR: 0.89, 95% CI: 0.85 to 0.93, p < 0.001). Reduced associations with violent charges remained in most sensitivity analyses, while associations with psychiatric hospitalisations and suicidal behaviour were inconsistent. Limitations include that the within-individual model does not account for confounders that could change during treatment, unless measured and adjusted for in the model. In this population-wide study, we found no consistent links between β-blockers and psychiatric outcomes. However, β-blockers were associated with reductions in violence, which remained in sensitivity analyses. The use of β-blockers to manage aggression and violence could be investigated further.

Association of Pharmacological Treatments and Hospitalization and Death in Individuals With Amphetamine Use Disorders in a Swedish Nationwide Cohort of 13 965 Patients

There are no medications approved by authorities for the treatment of amphetamine or methamphetamine dependence, and studies investigating the effectiveness of pharmacological treatments in hard outcomes, such as hospitalization and death, are lacking. To investigate the association between pharmacotherapies and hospitalization and mortality outcomes in persons with amphetamine or methamphetamine use disorder. This nationwide register-based cohort study was conducted from July 2006 to December 2018 with a median (IQR) follow-up time of 3.9 (1.0-6.1) years. Data were analyzed from December 1, 2021, to May 24, 2022. All residents aged 16 to 64 years living in Sweden with a registered first-time diagnosis of amphetamine or methamphetamine use disorder and without previous diagnoses of schizophrenia or bipolar disorder were identified from nationwide registers of inpatient care, specialized outpatient care, sickness absence, and disability pension. Medications for substance use disorders (SUDs) or for attention-deficit/hyperactive disorder, mood stabilizers, antidepressants, benzodiazepines and related drugs, and antipsychotics. Medication use vs nonuse was modeled with the PRE2DUP (from prescription drug purchases to drug use periods) method. Primary outcomes were hospitalization due to SUD and any hospitalization or death, which were analyzed using within-individual models by comparing use and nonuse periods of 17 specific medications or medication classes in the same individual to minimize selection bias. The secondary outcome was all-cause mortality, studied using between-individual analysis as traditional Cox models. There were 13 965 individuals in the cohort (9671 [69.3%] male; mean [SD] age, 34.4 [13.0] years). During follow-up, 7543 individuals (54.0%) were taking antidepressants, 6101 (43.7%) benzodiazepines, 5067 (36.3%) antipsychotics, 3941 (28.2%) ADHD medications (1511 [10.8%] were taking lisdexamphetamine), 2856 (20.5%) SUD medications, and 1706 (12.2%) mood stabilizers. A total of 10 341 patients (74.0%) were hospitalized due to SUDs, 11 492 patients (82.3%) were hospitalized due to any cause or died, and 1321 patients (9.5%) died of any cause. Lisdexamphetamine was the only medication in this study that was significantly associated with a decrease in risk of 3 outcomes (adjusted hazard ratio [aHR], 0.82; 95% CI, 0.72-0.94 for SUD hospitalization; aHR, 0.86; 95% CI, 0.78-0.95 for any hospitalization or death; aHR, 0.43; 95% CI, 0.24-0.77 for all-cause mortality). Methylphenidate use also was associated with lower all-cause mortality (aHR, 0.56; 95% CI, 0.43-0.74). Use of benzodiazepines was associated with a significantly higher risk of SUD hospitalization (aHR, 1.17; 95% CI, 1.12-1.22), any hospitalization or death (aHR, 1.20; 95% CI, 1.17-1.24), and all-cause mortality (aHR, 1.39; 95% CI, 1.20-1.60). Use of antidepressants or antipsychotics was associated with a slight increase in risk of SUD hospitalization (aHR, 1.07; 95% CI, 1.03-1.11 and aHR, 1.05; 95% CI, 1.01-1.09) as well as any hospitalization or death (aHR, 1.10; 95% CI, 1.06-1.14 and aHR, 1.06; 95% CI, 1.03-1.10, respectively). In this study, use of lisdexamphetamine was associated with improved outcomes in persons with amphetamine or methamphetamine use disorders, encouraging the conduct of randomized clinical trials. Prescription benzodiazepine use was associated with poor outcomes.

Adolescents’ primary care consultations before and after parental suicide: evidence from population-wide data

Parental bereavement is associated with distress and poorer long-term outcomes among adolescents. Adolescents who lose a parent to suicide fare worse than their peers even before bereavement. Based on the current literature, we cannot distinguish such initial differences from the medium and long-term effect of parental suicide. We study the impact of parental suicide on adolescents’ General Practitioner visits for mental health or psychosocial reasons. Within-individual models account for time-invariant differences between the bereaved and non-bereaved. We investigate if effects differ from the impact of parental death from other causes, and vary with sex and socioeconomic background. Full population data on Norwegian residents aged 10–19 in the period 2006–2015 are drawn from registers (N = 1 405 suicide bereaved, 12 982 bereaved by other causes, and 1 182 819 non-bereaved controls). Records include data on use of health services, parental mortality, and sociodemographic characteristics of parent and child. Mental health consultations increase gradually in the quarters leading up to the parental suicide, significantly more for girls than for boys. Two years prior to bereavement, 2.4% of the subsequently suicide bereaved have a mental health consultation in any given quarter. In the year of bereavement, this increases with 6% points. Health care workers should be aware that boys are less likely to turn to their GP for support before parental bereavement from suicide.

Associations between antipsychotic use, substance use and relapse risk in patients with schizophrenia: real-world evidence from two national cohorts.

Research on the effectiveness of pharmacotherapies for schizophrenia and comorbid substance use disorder (SUD) is very sparse, and non-existent on the prevention of the development of SUDs in patients with schizophrenia. To compare the real-world effectiveness of antipsychotics in schizophrenia in decreasing risk of developing an initial SUD, and psychiatric hospital admission and SUD-related hospital admission among patients with an SUD. Two independent national cohorts including all persons diagnosed with schizophrenia (N = 45 476) were followed up for 22 (Finland: 1996-2017) and 11 (Sweden: 2006-2016) years. Risk of developing an SUD was calculated with between-individual models, and risks of psychiatric and SUD-related hospital admission were calculated with within-individual models, using Cox regression and adjusted hazard ratios (aHRs) for using versus not using certain antipsychotics. For patients with schizophrenia without an SUD, clozapine use (Finland: aHR 0.20, 95% CI 0.16-0.24, P < 0.001; Sweden: aHR 0.35, 95% CI 0.24-0.50, P < 0.001) was associated with lowest risk of developing an initial SUD in both countries. Antipsychotic polytherapy was associated with second lowest risk (aHR 0.54, 95% CI 0.44-0.66) in Sweden, and third lowest risk (aHR 0.47, 95% CI 0.42-0.53) in Finland. Risk of relapse (psychiatric hospital admission and SUD-related hospital admission) were lowest for clozapine, antipsychotic polytherapy and long-acting injectables in both countries. Results were consistent across both countries. Clozapine and antipsychotic polytherapy are most strongly associated with reduced risk of developing SUDs among patients with schizophrenia, and with lower relapse rates among patients with both diagnoses.

Allopurinol, dipyridamole and calcium channel blockers in the treatment of bipolar disorder – A nationwide cohort study

BackgroundImproved treatments for bipolar disorder (BD) are needed. Drug repurposing aims to find novel targets for drugs that have been used for other indications. This study investigated the risk of psychiatric hospitalization associated with use of calcium-channel blockers (CCBs; dihydropyridines, diltiazem, verapamil) and adenosine modulators (allopurinol, dipyridamole) in BD in within-individual design. MethodsIndividuals diagnosed with BD (ICD-10: F30-F31) were identified from the inpatient, specialized outpatient, sickness absence, and disability pension registers during 1996–2018 in Finland (N = 60,045). The main outcome was hospitalization due to affective symptoms (ICD-10: F30-F39). Within-individual models in stratified Cox regression were used and adjusted hazard ratios (aHR) with 95 % confidence intervals (CIs) reported. ResultsUse of CCBs was associated with a decreased risk of hospitalization due to affective symptoms (aHR 0.83, 95 % CI 0.78–0.88) when all CCBs were analyzed together. Of specific CCBs, use of diltiazem (0.71, 0.55–0.91) and dihydropyridines (0.83, 0.78–0.89) were associated with a decreased risk but verapamil was not (0.93, 0.73–1.19). Use of adenosine modulators in general was associated with a decreased risk of hospitalizations due to affective symptoms (0.87, 0.79–0.96). Both allopurinol (0.85, 0.74–0.97) and dipyridamole (0.89, 0.78–1.00) were associated with a marginally decreased risk. Thiazide diuretic use as a negative control was not associated with the risk of hospitalization due to affective symptoms (0.97, 0.83–1.13). LimitationsDue to the observational nature of this study, causation cannot be confirmed. ConclusionsDihydropyridines and diltiazem were associated with a decreased risk of psychiatric hospitalization in bipolar disorder. Results for allopurinol and dipyridamole were inconclusive.

Adenosine modulators and calcium channel blockers as add-on treatment for schizophrenia

Relapses remain common among individuals with schizophrenia indicating a need for improved treatments. Creating a completely new drug molecule is expensive and time consuming, and therefore drug repurposing should be considered. Aim of this study was to investigate the risk of psychiatric rehospitalization associated with use of adenosine modulators (AMs) and calcium channel blockers (CCBs) in schizophrenia. Individuals diagnosed with schizophrenia (N = 61,889) in inpatient care between 1972–2014 in Finland were included. The follow-up lasted from 1996 to 2017. Main exposures were use of AMs (allopurinol and dipyridamole) and CCBs (dihydropyridines, diltiazem, and verapamil). Thiazide diuretics were used as a negative control. Within-individual models in stratified Cox regression were used and adjusted hazard ratios (HR) with 95% confidence intervals (CIs) are reported. Use of AMs was associated with a reduced risk of psychiatric rehospitalization on drug class level (HR 0.74, 95% CI 0.65–0.84, P < 0.0001), as well as on the level of individual drugs (allopurinol HR 0.82, 95% CI 0.70–0.97, P = 0.02; dipyridamole HR 0.65, 95% CI 0.55–0.77, P < 0.0001). Use of CCBs was associated with a reduced risk of psychiatric rehospitalization on drug class level (HR 0.81, 95% CI 0.77–0.86, P < 0.0001). From the different CCBs, only exposure to dihydropyridines was associated with a reduced risk (HR 0.79, 95% CI 0.74–0.84, P < 0.0001). No effect was observed for the negative control, thiazide diuretics (HR 0.96, 0.90–1.02, P = 0.20). The effects of dipyridamole and dihydropyridines were more pronounced among younger persons and combination of AMs, and CCBs was associated with a lower risk than either drug class as monotherapy. These results indicate a need for randomized controlled trials of these drugs.

A longitudinal study of changes in interactional justice and subsequent short-term sickness absence among municipal employees.

Objectives:Level of perceived interactional justice has been shown to be associated with sickness absence, but less is known about the effects of changes in interactional justice. It is also unknown to what extent unmeasured, time-invariant differences contribute to the association. We investigated the association between interactional justice changes and subsequent short-term (1–3 days) sickness absences over a 12-year follow-up using between- and within-individual modeling among ageing municipal employees.Methods:The data was derived from Helsinki Health Study cohort with baseline survey in 2000–2002 (N=8960, response rate 67%) and follow-up surveys in 2007 and 2012 (response rates 79% and 83%, respectively). At baseline, participants were 40–60-year-old employees of the City of Helsinki, Finland. Sickness absences from the employer’s registry were linked with the responses (78%). The analytic sample was 2109 and 2070 individuals for between-individual and 4433 individuals and 8425 observations for within-individual associations.Results:Negative change in interactional justice was associated with an increased risk of short-term sickness absence in between-individual models after adjusting for age and gender. Adjustment for sickness absence history attenuated the association. In within-individual models, a negative change in perceived interactional justice was associated with an increased risk of short-term sickness absence spells [incidence rate ratios (IRR) 1.05 (95% confidence interval 1.01–1.09)]. This association was robust to adjustments for gender, age, health behaviors and sickness absence history.Conclusions:Paying attention to management principles – especially managerial behavior and treatment of employees to avoid the deterioration of the level of interactional justice – may provide a way of reducing self-certified short-term sickness absence spells.

S210. COMPARATIVE EFFECTIVENESS OF ANTIPSYCHOTICS FOR RISK OF ATTEMPTED OR COMPLETED SUICIDE AMONG PERSONS WITH SCHIZOPHRENIA

BackgroundSuicidal attempts and suicide are rather common phenomena in persons with schizophrenia whom are 6–14 times more likely to die due to suicide than the general population. Very little is known on effectiveness of antipsychotics in preventing suicide attempts and completed suicides among patients with schizophrenia. Whether all antipsychotics are effective in preventing attempted or completed suicides also remains unclear. The objective of our study was to investigate comparative effectiveness of antipsychotics for risk of attempted or completed suicide among all patients with schizophrenia in Finland and Sweden.MethodsTwo nationwide register-based cohort studies were conducted including all individuals with schizophrenia in Finland (N=61889) and Sweden (N=29823). The Finnish cohort included all persons treated for schizophrenia in inpatient care (1972–2014), with follow-up for drug use and outcomes during 1996–2017. The Swedish cohort included all persons with treatment contact due to schizophrenia in inpatient or specialized outpatient care, sickness absence, or disability pension (2006–2013), with follow-up for drug use and outcomes during 2006–2016. The main exposure included the ten most commonly used antipsychotic monotherapies, and also adjunctive pharmacotherapies (antidepressants, mood stabilizers, lithium, benzodiazepines and related drugs were investigated). The main outcome measure was attempted or completed suicide which was analyzed with within-individual models by comparing use and non-use periods in the same individual. Sensitivity analyses were conducted by between-individual models, with attempted suicide (hospitalization only) as an outcome, and by censoring first 30 days from each exposure. Results are reported as hazard ratios (HRs) with 95 % confidence intervals (95% CI).ResultsCompared with no use of antipsychotics, clozapine was the only antipsychotic therapy consistently associated with a decreased risk of suicidal outcomes. Hazard ratios (HRs) and 95% CI for attempted or completed suicide were 0.64 (95% CI 0.49–0.84) in the Finnish cohort, and 0.66 (0.43–0.99) in the Swedish cohort, and for attempted suicide 0.60 (0.46–0.79) in the Finnish cohort and 0.62 (0.40–0.95) in the Swedish cohort. No other antipsychotic was associated with a reduced risk of attempted and/or completed suicide than clozapine. Regarding adjunctive pharmacotherapies, benzodiazepines and Z-drugs were associated with an increased risk of suicide attempts or deaths (HRs for benzodiazepines 1.29–1.30 and 1.33–1.62 for Z-drugs, not reaching statistical significance in the Swedish cohort).DiscussionThe results from two large nationwide cohorts provide the first evidence on comparative real-world effectiveness of specific antipsychotics in the prevention of severe suicidal behavior. Clozapine was the only pharmacological treatment associated with a substantially decreased risk of attempted or completed suicide and should be considered as a first-line treatment for patients with suicidal ideation or behavior.

Depression, violence and cortisol awakening response: a 3-year longitudinal study in adolescents.

Despite evidence of links between depression and violent outcomes, potential moderators of this association remain unknown. The current study tested whether a biological marker, cortisol, moderated this association in a longitudinal sample of adolescents. Participants were 358 Dutch adolescents (205 boys) with a mean age of 15 years at the first measurement. Depressive symptoms, the cortisol awakening response (CAR) and violent outcomes were measured annually across 3 years. The CAR was assessed by two measures: waking cortisol activity (CAR area under the curve ground) and waking cortisol reactivity (CAR area under the curve increase). Within-individual regression models were adopted to test the interaction effects between depressive symptoms and CAR on violent outcomes, which accounted for all time-invariant factors such as genetic factors and early environments. We additionally adjusted for time-varying factors including alcohol drinking, substance use and stressful life events. In this community sample, 24% of adolescents perpetrated violent behaviours over 3 years. We found that CAR moderated the effects of depressive symptoms on adolescent violent outcomes (βs ranged from -0.12 to -0.28). In particular, when the CAR was low, depressive symptoms were positively associated with violent outcomes in within-individual models, whereas the associations were reversed when the CAR was high. Our findings suggest that the CAR should be investigated further as a potential biological marker for violence in adolescents with high levels of depressive symptoms.

Legal Socialization and Self-Reported Criminal Offending: The Role of Procedural Justice and Legal Orientations

The procedural justice model of legal socialization holds that personal fairness judgments influence criminal offending directly and indirectly, via legal orientations (e.g. legitimacy and legal cynicism). This study used longitudinal data to empirically scrutinize these arguments. Using 11 waves of data from the Pathways to Desistance study (i.e. baseline and 10 follow-up interviews), a series of time-lagged, multi-level longitudinal regression models with time-varying and time-stable measures decomposed into between- and within-individual components were estimated. The estimates from the linear mixed-effects models showed that procedural justice judgments directly influence legitimacy and, though relatively more limited, legal cynicism over time both between- and within-individuals. Test statistics indicated too that positive procedural justice judgments reduce involvement in criminal offending between individuals. However, legitimacy is found to significantly mediate the effect of personal procedural justice judgments. The effect of vicarious procedural justice judgments remained statistically significant in explaining differences in criminal offending. As for the within-individual model, neither procedural justice scale predicted offending. However, legal cynicism did have a direct significant effect in the within-individual offending model. The findings support key elements legal socialization theory, especially the premise that the way in which criminal justice authorities treat the individuals they come into contact with influences (albeit indirectly) subsequent compliance with the law.

Triggers for Violent Criminality in Patients With Psychotic Disorders.

Absolute and relative risks of violence are increased in patients with psychotic disorders, but the contribution of triggers for violent acts to these risks is uncertain. To examine whether a range of triggers for violent acts are associated with risks of violence in patients diagnosed with psychotic disorders and in individuals without a psychiatric diagnosis. Using a sample of all individuals born in Sweden between 1958 and 1988 (N = 3 123 724), we identified patients in the National Patient Register who were diagnosed with schizophrenia spectrum disorders (n = 34 903) and bipolar disorder (n = 29 692), as well as unaffected controls (n = 2 763 012). We then identified, within each subsample, persons who had experienced any of the following triggers for violent acts between January 1, 2001, and December 15, 2013: exposure to violence, parental bereavement, self-harm, traumatic brain injury, unintentional injuries, and substance intoxication. By using within-individual models, we conducted conditional logistic regression to compare the risk of the individual engaging in violent acts in the week following the exposure to a trigger with the risk during earlier periods of equivalent length. All time-invariant confounders (eg, genetic and early environmental influences) were controlled for by this research design and we further adjusted for time-varying sociodemographic factors. Adjusted odds ratios (aORs) of violent crime occurring in the week following the exposure to a trigger event compared with earlier periods. Among the sample of 2 827 607 individuals (1 492 186 male and 1 335 421 female), all of the examined trigger events were associated with increased risk of violent crime in the week following exposure. The largest 1-week absolute risk of violent crime was observed following exposure to violence (70-177 violent crimes per 10 000 persons). For most triggers, the relative risks did not vary significantly by diagnosis, including unintentional injuries (aOR range, 3.5-4.8), self-harm (aOR range, 3.9-4.2), and substance intoxication (aOR range, 3.0-4.0). Differences by diagnosis included parental bereavement, which was significantly higher in patients with schizophrenia spectrum disorders (aOR, 5.0; 95% CI, 3.0-8.1) compared with controls (aOR, 1.7; 95% CI, 1.3-2.2). In addition to identifying risk factors for violence, clarifying the timing of the triggers may provide opportunities to improve risk assessment and management in individuals with psychotic disorders.

Moving in and out of Poverty: The Within-Individual Association between Socioeconomic Status and Juvenile Delinquency.

A family’s SES can be changeable over time. This study was the first to investigate if such within-individual changes in family SES are associated with parallel fluctuations in boys’ delinquent behavior from childhood to adolescence. Participants were a community sample of boys and their caregivers (N = 503) who were assessed annually for ten consecutive years spanning ages 7–18. Fixed effects models revealed that changes in familial SES were related to changes in delinquency: Youths were more likely to offend during years in which their parents’ SES was lower than during years in which their parents’ SES was higher. Contrary to expectations, we found no evidence that this association was accounted for by families moving to different neighborhoods or by changes in parenting. Since within-individual models provide a stricter test of causality than between-individual models, these findings support claims that impacting familial SES may have a direct effect on youths’ delinquency.

Selective Serotonin Reuptake Inhibitors and Violent Crime: A Cohort Study.

BackgroundAlthough selective serotonin reuptake inhibitors (SSRIs) are widely prescribed, associations with violence are uncertain.Methods and FindingsFrom Swedish national registers we extracted information on 856,493 individuals who were prescribed SSRIs, and subsequent violent crimes during 2006 through 2009. We used stratified Cox regression analyses to compare the rate of violent crime while individuals were prescribed these medications with the rate in the same individuals while not receiving medication. Adjustments were made for other psychotropic medications. Information on all medications was extracted from the Swedish Prescribed Drug Register, with complete national data on all dispensed medications. Information on violent crime convictions was extracted from the Swedish national crime register. Using within-individual models, there was an overall association between SSRIs and violent crime convictions (hazard ratio [HR] = 1.19, 95% CI 1.08–1.32, p < 0.001, absolute risk = 1.0%). With age stratification, there was a significant association between SSRIs and violent crime convictions for individuals aged 15 to 24 y (HR = 1.43, 95% CI 1.19–1.73, p < 0.001, absolute risk = 3.0%). However, there were no significant associations in those aged 25–34 y (HR = 1.20, 95% CI 0.95–1.52, p = 0.125, absolute risk = 1.6%), in those aged 35–44 y (HR = 1.06, 95% CI 0.83–1.35, p = 0.666, absolute risk = 1.2%), or in those aged 45 y or older (HR = 1.07, 95% CI 0.84–1.35, p = 0.594, absolute risk = 0.3%). Associations in those aged 15 to 24 y were also found for violent crime arrests with preliminary investigations (HR = 1.28, 95% CI 1.16–1.41, p < 0.001), non-violent crime convictions (HR = 1.22, 95% CI 1.10–1.34, p < 0.001), non-violent crime arrests (HR = 1.13, 95% CI 1.07–1.20, p < 0.001), non-fatal injuries from accidents (HR = 1.29, 95% CI 1.22–1.36, p < 0.001), and emergency inpatient or outpatient treatment for alcohol intoxication or misuse (HR = 1.98, 95% CI 1.76–2.21, p < 0.001). With age and sex stratification, there was a significant association between SSRIs and violent crime convictions for males aged 15 to 24 y (HR = 1.40, 95% CI 1.13–1.73, p = 0.002) and females aged 15 to 24 y (HR = 1.75, 95% CI 1.08–2.84, p = 0.023). However, there were no significant associations in those aged 25 y or older. One important limitation is that we were unable to fully account for time-varying factors.ConclusionsThe association between SSRIs and violent crime convictions and violent crime arrests varied by age group. The increased risk we found in young people needs validation in other studies.

Rising to the challenge: Deep acting is more beneficial when tasks are appraised as challenging.

Cumulative research indicates that deep acting has a nonsignificant relationship with employee exhaustion, despite arguments that deep acting can be beneficial. To illuminate when deep acting leads to more positive employee outcomes, we draw on the resource conservation perspective to propose a within-individual model of deep acting that focuses on service employees' daily fluctuation of emotional labor and emotional exhaustion. Specifically, we propose that the ongoing experience of felt challenge is a within-person boundary condition that moderates deep acting's relationship with emotional exhaustion, and model emotional exhaustion as a mediating mechanism that subsequently predicts momentary job satisfaction and daily customer conflict handling. Using an experience sampling design, we collected data from 84 service employees over a 3-week period. Deep acting was less emotionally exhausting for service providers when they saw their tasks as more challenging. Furthermore, emotional exhaustion mediated the deep acting by felt challenge interaction effect on momentary job satisfaction and daily customer conflict handling. The findings contribute to a better understanding of the deep acting experience at work, while highlighting customer conflict handling as a key behavioral outcome of emotional labor.

The Strength-of-Weak-Ties Hypothesis in China Revisited: Evidence from Within-Individual Models

While the strength-of-weak-ties hypothesis (SWT) is theoretically plausible and appears to be well supported by research in Western market economies, scholars contend that it does not hold in China...

Multilevel analysis of temperature dependent near-infrared spectra

Quantitative spectra-temperature relationship (QSTR) between near-infrared (NIR) spectra and temperature has been used for quantitative determination of the compositions in mixtures. In this work, QSTR is studied using multilevel simultaneous component analysis (MSCA) and the spectral data of the samples with different concentrations measured at different temperatures. MSCA model contains a between-individual model describing the differences between the individuals and a within-individual model capturing the differences within the data of all the individuals. NIR spectra of five different compositions (water–ethanol–isopropanol) measured at seven temperatures were analyzed. A between-temperature model describing the effect of temperature and a within-temperature model describing the variation of concentration were obtained, from which QSTR model is established and quantitative analysis is achieved. Furthermore, the difference between the between-temperature or within-temperature models of different mixtures is used to study the composition of the solvent.

An analysis of categorical repeated measurements in the presence of an external factor

SUMMARY This paper provides a log-linear method for the analysis of contingency tables where the population of individuals is divided into distinct subpopulations and where repeated measurements are made on each individual. The proposed model for the full joint probabilities is quasi-symmetry within each subpopulation; the model is derived from one of two within-individual models. The method by which the hypotheses that flow from the model are tested is an extension of the test of marginal symmetry, achieved by testing complete symmetry conditional on quasi-symmetry.

Variable selection in a linear growth curve model with autoregressive within-individual errors

In this paper, we consider variable selection schemes in a linear random coefficient growth curve model. Unbalanced within-individual data is assumed to have first-order linear correlation (p). A variable selection scheme suggested in the between-individual model is a weighted stepwise selection. A sim-ulation study is conducted to compare the performances of the maximum likelihood (ML) and the ordinary least square (OLS) estimators in the within-individual regression model in terms of the ability of variable selection in the between-individual model. Simulation results indicate the following: Under the suspicion of high autocorrelation error (p>0.5), the ML estimation is necessary in the within-individual model. When it is believed that the p is as small as 0.1 and the heterogeneity of variance is relatively low then, the OLS estimator can replace the ML estimator in terms of selection performance in the between-individual model.