Association of Resting Heart Rate and Heart Rate Variability With Proximal Suicidal Risk in Patients With Diverse Psychiatric Diagnoses

A Swedish population-based study to evaluate the usefulness of resting heart rate in the prediction of suicidal behavior among males

INTRODUCTION

Resting heart rate has been distinctly related to both internalizing (high pulse) and externalizing (low pulse) disorders. We aimed to explore the associations between resting heart rate and suicidal behavior (nonfatal suicide attempt [SA] and suicide death [SD]) and evaluate if such associations exist beyond the effects of internalizing/externalizing symptomatology.

METHOD

We used Cox proportional hazards models to evaluate the associations between resting heart rate (age 19) and later SA/SD in 357,290 Swedish men. Models were controlled for internalizing disorders, externalizing disorders, and resilience (the ability to deal with adversity). Co-relative analysis (comparing pairs of different genetic relatedness) was used to control for unmeasured family confounders and improve causal inference.

RESULTS

In baseline models, low resting heart rate was associated with SA (HR = 0.96; 95% CI: 0.95,0.98) and high resting heart rate with SD (HR = 1.04; 95% CI: 1.002,1.07). The association with SA remained after adjustment for all confounders (HR = 0.98). However, the association with SD did not persist after controlling for covariates. Co-relative analysis did not support causal associations.

CONCLUSIONS

Our findings raise interesting etiological questions for the understanding of suicidal behaviors but do not support the usefulness of resting heart rate in suicide prediction.

Heart Rate Variability as a Translational Dynamic Biomarker of Altered Autonomic Function in Health and Psychiatric Disease

The autonomic nervous system (ANS) is responsible for the precise regulation of tissue functions and organs and, thus, is crucial for optimal stress reactivity, adaptive responses and health in basic and challenged states (survival). The fine-tuning of central ANS activity relies on the internal central autonomic regulation system of the central autonomic network (CAN), while the peripheral activity relies mainly on the two main and interdependent peripheral ANS tracts, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). In disease, autonomic imbalance is associated with decreased dynamic adaptability and increased morbidity and mortality. Acute or prolonged autonomic dysregulation, as observed in stress-related disorders, affects CAN core centers, thereby altering downstream peripheral ANS function. One of the best established and most widely used non-invasive methods for the quantitative assessment of ANS activity is the computerized analysis of heart rate variability (HRV). HRV, which is determined by different methods from those used to determine the fluctuation of instantaneous heart rate (HR), has been used in many studies as a powerful index of autonomic (re)activity and an indicator of cardiac risk and ageing. Psychiatric patients regularly show altered autonomic function with increased HR, reduced HRV and blunted diurnal/circadian changes compared to the healthy state. The aim of this article is to provide basic knowledge on ANS function and (re)activity assessment and, thus, to support a much broader use of HRV as a valid, transdiagnostic and fully translational dynamic biomarker of stress system sensitivity and vulnerability to stress-related disorders in neuroscience research and clinical psychiatric practice. In particular, we review the functional levels of central and peripheral ANS control, the main neurobiophysiologic theoretical models (e.g., polyvagal theory, neurovisceral integration model), the precise autonomic influence on cardiac function and the definition and main aspects of HRV and its different measures (i.e., time, frequency and nonlinear domains). We also provide recommendations for the proper use of electrocardiogram recordings for HRV assessment in clinical and research settings and highlight pathophysiological, clinical and research implications for a better functional understanding of the neural and molecular mechanisms underlying healthy and malfunctioning brain-heart interactions in individual stress reactivity and psychiatric disorders.

An RDoC-based approach to adolescent self-injurious thoughts and behaviors: The interactive role of social affiliation and cardiac arousal

Recent theoretical models have posited that increases in self-injurious thoughts and behaviors (SITBs) during adolescence may be linked to failures in biological stress regulation in contexts of social stress. However, there is a lack of data examining this hypothesis during the transition to adolescence, a sensitive period of development characterized by changes across socioaffective and psychophysiological domains. Building on principles from developmental psychopathology and the RDoC framework, the present study used a longitudinal design in a sample of 147 adolescents to test whether interactions among experiences of social (i.e., parent and peer) conflict and cardiac arousal (i.e., resting heart rate) predicted adolescents' engagement in SITBs (i.e., nonsuicidal self-injury, NSSI; and suicidal ideation; SI) across 1-year follow-up. Prospective analyses revealed that adolescents experiencing a combination of greater peer, but not family, conflict and higher cardiac arousal at baseline showed significant longitudinal increases in NSSI. In contrast, social conflict did not interact with cardiac arousal to predict future SI. Findings indicate that greater peer-related interpersonal stress in adolescents may increase risk for future NSSI among youth with physiological vulnerabilities (i.e., higher resting heart rate) that may be markers of maladaptive stress responses. Future research should examine these processes at finer timescales to elucidate whether these factors are proximal predictors of within-day SITBs.

Development of Autonomic Nervous System Assays as Point-of-Care Tests to Supplement Clinical Judgment in Risk Assessment for Suicidal Behavior: A Review

PURPOSE OF REVIEW

A biomarker point-of-care (POC) test that supplements the psychiatric interview and improves detection of patients at risk for suicide would be of value, and assays of autonomic nervous system (ANS) activity would satisfy the logistical requirements for a POC test. We performed a selective review of the available literature of ANS assays related to risk for suicide.

RECENT FINDINGS

We searched PubMed and Web of Science with the strategy: "suicide OR suicidal" AND "electrodermal OR heart rate variability OR pupillometry OR pupillography." The search produced 119 items, 21 of which provided original data regarding ANS methods and suicide. These 21 studies included 6 for electrodermal activity, 14 for heart rate variability, and 1 for the pupillary light reflex. The 21 papers showed associations between ANS assays and suicide risk in a direction suggesting underlying hyperarousal in patients at risk for suicide. ANS assays show promise for future development as POC tests to supplement clinical decision making in estimating risk for suicide.

Chloroquine/Hydroxychloroquine Use and Suicide Risk: Hypotheses for Confluent Etiopathogenetic Mechanisms?

Chloroquine (CQ) and hydroxychloroquine (HCQ) are classical anti-malarial and anti-inflammatory treatments, which were used as first-line therapy at the beginning of the 2019 coronavirus disease (COVID-19) pandemic. Besides the emerging data on their lack of efficacy against COVID-19 infection, such treatments have been associated with some severe health concerns, including those of neuropsychiatric nature, such as a possible increase in suicide risk. Here we report a case of a patient with no history of psychiatric illnesses, who abruptly developed depression with melancholic features, severe suicidal ideation (SI), and attempted suicide (SA) shortly after receiving HCQ for his COVID-19 infection. The case was followed by a mini-review of the heterogeneous scientific literature on the hypothetical association between neuropsychiatric symptoms, with a focus on SI and suicidal behavior (SB, including SA and death by suicide), when CQ and HCQ are used in COVID-19, rheumatologic diseases, and malaria settings. Considering the anti-inflammatory properties of CQ and HCQ and the implications for neuroinflammation in suicide pathogenesis, the possible increase in suicide risk caused by these medications appears paradoxical and suggests that other underlying pathological trajectories might account for this eventuality. In this regard, some of these latter mechanistic postulates were proposed. Certainly the role and contribution of psycho-social factors that a COVID-19 patient had to face can neither be minimized nor excluded in the attempt to understand his suffering until the development of SI/SB. However, while this case report represents a rare scenario in clinical practice and no consensus exists in the literature on this topic, a psychiatric screening for suicide risk in patients using of CQ and HCQ could be carefully considered.