Introduction
Power analysis is critical for both planning future research samples and evaluating the reasonability of answers produced by pre‐existing and fixed samples. Unfortunately, the ...irregularity of suicide‐related data and the need for increasingly complex models in suicide research can make traditional power formulas inaccurate or even unusable. Ignoring these common problems risks both over‐ and under‐recruiting, as well as obscuring the true quality of the results (up and down) to future reviewers and readers.
Method
A better option is to use Monte Carlo power simulations.
Results
These techniques produce answers that are equivalent to traditional power formulas when traditional assumptions are met, but produce more accurate results in the common case when those assumptions are violated.
Conclusion
What follows is a tutorial on how suicide researchers can conduct such simulations. It begins by building the reader’s intuition for why simulations work, followed by two worked examples in R. Discussion also includes guidelines for conducting and reporting simulations, along with answers to frequently asked questions. Appendices provide code examples researchers can model and adapt to their own simulations as needed.
During the opening moves of a chess game, a player (typically White) may offer a number of gambits, which involve sacrificing a chess piece for an opponent for capture to achieve long‐term positional ...advantages. One of the most popular gambits is called the Queen's Gambit and involves White offering a pawn to Black, which will open a lane for White's Queen if accepted by Black. In the present study, the generalized matching law (GML) was applied to chess openings involving the Queen's Gambit using over 71,000 archived chess games. Overall, chess players' opening moves involving the Queen's Gambit exhibited orderly matching as predicted by the GML, and the GML accounted for more variance in players' chess decision making as their relative playing experience increased. This study provides support for the generality of the GML and its application to complex operant behavior outside of laboratory contexts.
Summary
Objective
Research suggests that individuals seeking weight loss treatment do so for a variety of reasons. Limited work has explored relations of reasons for weight loss to patient ...characteristics or to weight loss outcomes. The current study examined these relations.
Methods
The sample consisted of 588 patients in a 15‐week fee‐for‐service weight loss programme. Prior to the intervention, patients completed questionnaires including items on reasons for weight loss, demographic characteristics, and a variety of weight‐based characteristics. Patients' weight change outcomes were expressed as percent weight loss and also categorized into one of three previously described weight loss trajectories.
Results
The results of chi‐squared and t‐test analyses suggested that endorsement of health concerns, mobility concerns, or another person's recommendation was associated with higher body mass index (BMI) and older age. These reasons were more likely to be endorsed by White patients than Black patients and by male patients than female patients. Endorsement of doctor recommendation was more likely to be seen among Black patients than White patients. There was no significant relation of any weight loss reason with weight loss outcome.
Conclusions
While certain reasons for weight loss were more often cited by certain patient groups, no specific reason predicted a better or worse outcome.
Depletion of cholinergic neurons in the hippocampus has been implicated in memory impairment and Alzheimer's Disease (AD). The brain angiotensin AT₄ receptor is co-localized with cholinergic neurons, ...and the AT₄ receptor has also been implicated in cognitive processing. The current investigation used the spatial win-shift version of the radial arm maze to determine the involvement of AT₄ receptors in spatial working memory formation. We initially established that intrahippocampal scopolamine significantly impaired the spatial working memory performance of Sprague-Dawley rats in the radial arm maze. We also demonstrated that subsequent intrahippocampal infusions of Norleucine¹-Angiotensin IV (Nle¹-AngIV) significantly prevented the scopolamine-induced deficit. Consistent with previously published data on long-term spatial memory, our findings suggest that activation of AT₄ receptors can compensate for impaired spatial working memory resulting from compromised muscarinic acetylcholine receptor function. We further demonstrate that the hippocampus is a site of action for Nle¹-AngIV-mediated cognitive improvement.
Since the turn of the century, interdisciplinary research on networks-their formation, structure, and influence-has advanced so rapidly, it is now a science unto itself, offering new and powerful ...quantitative tools for studying human behavior, whose potential psychologists are just beginning to glimpse. Among these tools is a formula for quantifying assortativity, the propensity of similar people to be socially connected with one another more often than their dissimilar counterparts. With this formula, this investigation establishes a foundation for examining assortative patterns in suicidal behavior and highlights how they can be exploited for improved prevention. Specifically, the established clustering of suicide fatalities in time and space implies such fatalities have assortative features. This suggests other forms of suicide-related behavior may as well. Thus, the assortativity of suicide-related verbalizations (SRVs) was examined by machine coding 64 million posts from 17 million users of a large social media platform-Twitter-over 2 distinct 28-day periods. Users were defined as socially linked in the network if they mutually replied to each other at least once. Results show SRVs were significantly more assortative than chance, through 6 degrees of separation. This implies that if a person posts SRVs, their friends' friends' friends' friends' friends' friends are more likely than chance to do the same even though they have never met. SRVs also remained significantly assortative through 2 degrees, even when mood was controlled. Discussion illustrates how these assortative patterns can be exploited to improve the true-positive rate of suicide risk screenings.
The phenotype for posttraumatic stress disorder (PTSD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Diseases (DSM‐5) includes 20 symptoms in four clusters. In contrast, the ...PTSD model in the 11th revision of the International Classification of Diseases (ICD‐11) includes six symptoms in three clusters. Whether those six symptoms are, in fact, the most central symptoms of the PTSD phenotype remains an open question. In a previous network analysis of DSM‐5 PTSD symptoms, Mitchell and colleagues (2017) reported limited overlap between central PTSD symptoms and those in the ICD‐11 model in a national sample of U.S. veterans. The present study sought to replicate and extend upon these findings in a large national sample of U.S. adults (N = 2,953). Centrality statistics from both a replication sample (i.e., participants with DSM‐5 PTSD, n = 173) and an extension sample (i.e., participants who had been exposed to potentially traumatic events, n = 2,468) were moderately strongly convergent with the findings reported by Mitchell et al., rs = .54–.73. Additionally, only three of the six most central symptoms in both the replication and extension samples overlapped with the ICD‐11 model, indicating that the ICD‐11 model (a) failed to include network‐central symptoms of the PTSD phenotype and (b) included extra symptoms that were not network‐central. Several symptoms from the DSM‐5 Criterion D cluster (negative alterations in cognition and mood) that were excluded in ICD‐11 were found to be among the most central PTSD symptoms.
Childhood physical abuse is a major risk factor for suicide attempt, but factors that moderate this risk remain largely unexamined. Moderated mediation analysis was used with 186 adolescents who ...responded to the Profiles of Student Life: Attitudes and Behavior survey. Physical abuse increased risk directly and indirectly through reduced self‐esteem. Involvement in youth programs moderated the direct effect. Community service moderated the indirect effect. Results indicate 2 hours per week of involvement in youth programs and 2 hours per week of community service mitigated suicide attempt risk associated with abuse. Providing avenues for youth experiencing abuse to increase their community service and involvement is recommended.
Objective: On October 15, 2017, Alyssa Milano encouraged anyone who had been sexually harassed or assaulted to respond on Twitter with the phrase, #MeToo. Millions responded and a cultural reckoning ...ensued. Anecdotally, the #MeToo movement appears to have affected survivors' acceptance and acknowledgment of their own sexual assault experiences, but empirical evidence is lacking. To address this gap, the aim of this study was to examine associations between behavioral and labeled reports of sexual assault and time since the #MeToo movement began. Methods: Participants were 2,566 college students who completed a sexual assault survey over the course of 3 years, overlapping with the onset of the #MeToo movement. Results: Regarding our hypothesis that the prevalence of sexual assault-indicated by standardized behaviorally specific questions-would be relatively constant over time after controlling for demographics, a Bayesian logistic regression model yielded inconclusive results. However, among the 596 students who endorsed behaviorally specific screeners for sexual assault, a Bayesian linear regression model revealed that, after controlling for demographics and characteristics of the assault, participants were increasingly likely to label the experience a "sexual assault" with more time post-#MeToo. Conclusions: Overall, findings revealed no evidence for or against changes in the prevalence of sexual assault, but suggested there were associations between the #MeToo movement and greater recognition of past unwanted sexual experiences as "sexual assault" over time. These findings highlight the importance of considering the social context in research examining sexual assault survivors' cognitions.
Purpose
The structure of relationships in a social network affects the suicide risk of the people embedded within it. Although current interventions often modify the social perceptions (e.g., ...perceived support and sense of belonging) for people at elevated risk, few seek to directly modify the structure of their surrounding social networks. We show social network structure is a worthwhile intervention target in its own right.
Methods
A simple model illustrates the potential of interventions to modify social structure. The effect of these basic structural interventions on suicide risk is simulated and evaluated. Its results are briefly compared to emerging empirical findings for real network interventions.
Results
Even an intentionally simplified intervention on social network structure (i.e., random addition of social connections) is likely to be both effective and safe. Specifically, this illustrative intervention had a high probability of reducing the overall suicide risk, without increasing the risk of those who were healthy at baseline. It also frequently resolved stable, high-risk clusters of people at elevated risk. These illustrative results are generally consistent with emerging evidence from real social network interventions for suicide.
Conclusion
Social network structure is a neglected, but valuable intervention target for suicide prevention.
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