Associations between symptoms of depression and heart rate variability: An exploratory study

Dose-dependent response of prefrontal transcranial direct current stimulation on the heart rate variability: An electric field modeling study

Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) modulates the autonomic nervous system by activating deeper brain areas via top-down pathway. However, effects on the nervous system are heterogeneous and may depend on the amount of current that penetrates. Therefore, we aimed to investigate the variable effects of tDCS on heart rate variability (HRV), a measure of the functional state of the autonomic nervous system. Using three prefrontal tDCS protocols (1.5, 3 mA and sham), we associated the simulated individual electric field (E-field) magnitude in brain regions of interest with the HRV effects. This was a randomized, double-blinded, sham-controlled and within-subject trial, in which healthy young-adult participants received tDCS sessions separated by 2 weeks. The brain regions of interest were the dorsolateral PFC (DLPFC), anterior cingulate cortex, insula and amygdala. Overall, 37 participants were investigated, corresponding to a total of 111 tDCS sessions. The findings suggested that HRV, measured by root mean squared of successive differences (RMSSD) and high-frequency HRV (HF-HRV), were significantly increased by the 3.0 mA tDCS when compared to sham and 1.5 mA. No difference was found between sham and 1.5 mA. E-field analysis showed that all brain regions of interest were associated with the HRV outcomes. However, this significance was associated with the protocol intensity, rather than inter-individual brain structural variability. To conclude, our results suggest a dose-dependent effect of tDCS for HRV. Therefore, further research is warranted to investigate the optimal current dose to modulate HRV.

Developing a Five-Minute Normative Database of Heart Rate Variability for Diagnosing Cardiac Autonomic Dysregulation for Patients with Major Depressive Disorder

Heart rate variability (HRV) is related to cardiac vagal control and emotional regulation and an index for cardiac vagal control and cardiac autonomic activity. This study aimed to develop the Taiwan HRV normative database covering individuals aged 20 to 70 years and to assess its diagnosing validity in patients with major depressive disorder (MDD). A total of 311 healthy participants were in the HRV normative database and divided into five groups in 10-year age groups, and then the means and standard deviations of the HRV indices were calculated. We recruited 272 patients with MDD for cross-validation, compared their HRV indices with the normative database, and then converted them to Z-scores to explore the deviation of HRV in MDD patients from healthy groups. The results found a gradual decline in HRV indices with advancing age in the HC group, and females in the HC group exhibit higher cardiac vagal control and parasympathetic activity than males. Conversely, patients in the MDD group demonstrate lower HRV indices than those in the HC group, with their symptoms of depression and anxiety showing a negative correlation with HRV indices. The Taiwan HRV normative database has good psychometric characteristics of cross-validation.

Depression and coronary heart disease: mechanisms, interventions, and treatments

Coronary heart disease (CHD), a cardiovascular condition that poses a significant threat to human health and life, has imposed a substantial economic burden on the world. However, in contrast to conventional risk factors, depression emerges as a novel and independent risk factor for CHD. This condition impacts the onset and progression of CHD and elevates the risk of adverse cardiovascular prognostic events in those already affected by CHD. As a result, depression has garnered increasing global attention. Despite this growing awareness, the specific mechanisms through which depression contributes to the development of CHD remain unclear. Existing research suggests that depression primarily influences the inflammatory response, Hypothalamic-pituitary-adrenocortical axis (HPA) and Autonomic Nervous System (ANS) dysfunction, platelet activation, endothelial dysfunction, lipid metabolism disorders, and genetics, all of which play pivotal roles in CHD development. Furthermore, the effectiveness and safety of antidepressant treatment in CHD patients with comorbid depression and its potential impact on the prognosis of CHD patients have become subjects of controversy. Further investigation is warranted to address these unresolved questions.

Cardiovascular variations in patients with major depressive disorder versus bipolar disorder

BACKGROUND

Differentiating depression in major depressive disorder and bipolar disorder is challenging in clinical practice. Therefore, reliable biomarkers are urgently needed to differentiate between these diseases. This study's main objective was to assess whether cardiac autonomic function can distinguish patients with unipolar depression (UD), bipolar depression (BD), and bipolar mania (BM).

METHODS

We recruited 791 patients with mood disorders, including 191 with UD, 286 with BD, and 314 with BM, who had been drug free for at least 2 weeks. Cardiovascular status was measured using heart rate variability (HRV) and pulse wave velocity (PWV) indicators via finger photoplethysmography during a 5-min rest period.

RESULTS

Patients with BD showed lower HRV but higher heart rates than those with UD and BM. The PWV indicators were lower in the UD group than in the bipolar disorder group. The covariates of age, sex, and body mass index affected the cardiovascular characteristics. After adjusting for covariates, the HRV and PWV variations among the three groups remained significant. Comparisons between the UD and BD groups showed that the variable with the largest effect size was the frequency-domain indices of HRV, very low and high frequency, followed by heart rate. The area under the receiver operating characteristic curve (AUC) for each cardiovascular variable ranged from 0.661 to 0.714. The High-frequency index reached the highest AUC.

LIMITATIONS

Cross-sectional design and the magnitude of heterogeneity across participants with mood disorders limited our findings.

CONCLUSION

Patients with BD, but not BM, had a greater extent of cardiac imbalance than those with UD. Thus, HRV may serve as a psychophysiological biomarker for the differential diagnosis of UD and BD.

Inhibitory Neurons in Nucleus Tractus Solitarius Are Involved in Decrease of Heart Rate Variability and Development of Depression-Like Behaviors in Temporal Lobe Epilepsy

BACKGROUND

Diminished heart rate variability (HRV) has been observed in epilepsy, especially in epilepsy with depressive disorders. However, the underlying mechanism remains elusive.

METHODS

We studied HRV, spontaneous recurrent seizures, and depression-like behaviors in different phases of pilocarpine-induced temporal lobe epilepsy (TLE) in mice. Single-cell RNA sequencing analysis was used to identify various nerve cell subsets in TLE mice with and without depression. Differentially expressed gene (DEG) analysis was performed in epilepsy, depression, and HRV central control-related brain areas.

RESULTS

We found decreased HRV parameters in TLE mice, and alterations were positively correlated with the severity of depression-like behaviors. The severity of depression-like behaviors was correlated with the frequency of spontaneous recurrent seizure. Characteristic expression of mitochondria-related genes was significantly elevated in mice with depression in glial cells, and the enrichment analysis of those DEGs showed an enriched GABAergic synapse pathway in the HRV central control-related brain area. Furthermore, inhibitory neurons in the nucleus tractus solitarius, which is an HRV central control-related brain area, were specifically expressed in TLE mice combined with depression compared with those in mice without depression. A significantly enriched long-term depression pathway in DEGs from inhibitory neurons was found.

CONCLUSIONS

Our study reported correlations between HRV and epilepsy-depression comorbidity in different phases of TLE. More importantly, we found that HRV central control-related inhibitory neurons are involved in the development of depression in TLE, providing new insights into epilepsy comorbid with depression.

Heart Rate Fractality Disruption as a Footprint of Subthreshold Depressive Symptoms in a Healthy Population

OBJECTIVE

Psychopathology (and depression in particular) is a cardiovascular risk factor independent from any co-occurring pathology. This link is traced back to the mind-heart-body connection, whose underlying mechanisms are still not completely known. To study psychopathology in relation to the heart, it is necessary to observe the autonomic nervous system, which mediates among the parts of that connection. Its gold standard of evaluation is the study of heart rate variability (HRV). To investigate whether any association exists between the HRV parameters and sub-threshold depressive symptoms in a sample of healthy subjects.

METHOD

In this cross-sectional study, two short-term HRV recordings (5 min - supine and sitting) have been analyzed in 77 healthy subjects. Here we adopted a three-fold approach to evaluate HRV: a set of scores belonging to the time domain; to the frequency domain (high, low, and very low frequencies) and a set of 'nonlinear' parameters. The PHQ-9 (Patient Health Questionnaire-9) scale was used to detect depressive symptoms.

RESULTS

Depressive symptoms were associated only with a parameter from the non-linear approach and specifically the long-term fluctuations of fractal dimensions (DFA-α2). This association remained significant even after controlling for age, gender, BMI (Body-Mass-Index), arterial hypertension, anti-hypertensive drugs, dyslipidemia, and smoking habits. Moreover, the DFA-α2 was not affected by the baroreflex (postural change), unlike other autonomic markers.

CONCLUSIONS

Fractal analysis of HRV (DFA-α2) allows then to predict depressive symptoms below the diagnostic threshold in healthy subjects regardless of their health status. DFA-α2 may be considered as an imprint of subclinical depression on the heart rhythm.

Interictal Heart Rate Variability as a Biomarker for Comorbid Depressive Disorders among People with Epilepsy

Depressive disorders are common among people with epilepsy (PwE). We here aimed to report an unbiased automatic classification of epilepsy comorbid depressive disorder cases via training a linear support vector machine (SVM) model using the interictal heart rate variability (HRV) data. One hundred and eighty-six subjects participated in this study. Among all participants, we recorded demographic information, epilepsy states and neuropsychiatric features. For each subject, we performed simultaneous electrocardiography and electroencephalography recordings both in wakefulness and non-rapid eye movement (NREM) sleep stage. Using these data, we systematically explored the full parameter space in order to determine the most effective combinations of data to classify the depression status in PwE. PwE with depressive disorders exhibited significant alterations in HRV parameters, including decreased time domain and nonlinear domain values both in wakefulness and NREM sleep stage compared with without depressive disorders and non-epilepsy controls. Interestingly, PwE without depressive disorder showed the same level of HRV values as the non-epilepsy control subjects. The SVM classification model of PwE depression status achieved a higher classification accuracy with the combination of HRV parameters in wakefulness and NREM sleep stage. Furthermore, the receiver operating characteristic (ROC) curve of the SVM classification model showed a satisfying area under the ROC curve (AUC: 0.758). Intriguingly, we found that the HRV measurements during NREM sleep are particularly important for correct classification, suggesting a mechanistic link between the dysregulation of heart rate during sleep and the development of depressive disorders in PwE. Our classification model may provide an objective measurement to assess the depressive status in PwE.

Virtual Reality Therapy for Depression and Mood in Long-Term Care Facilities

Virtual reality (VR) describes a family of technologies which immerse users in sensorily-stimulating virtual environments. Such technologies have increasingly found applications in the treatment of neurological and mental health disorders. Depression, anxiety, and other mood abnormalities are of concern in the growing older population-especially those who reside in long-term care facilities (LTCFs). The transition from the familiar home environment to the foreign LTCF introduces a number of stressors that can precipitate depression. However, recent studies reveal that VR therapy (VRT) can promote positive emotionality and improve cognitive abilities in older people, both at home and in LTCFs. VR thus holds potential in allowing older individuals to gradually adapt to their new environments-thereby mitigating the detrimental effects of place attachment and social exclusion. Nevertheless, while the current psychological literature is promising, the implementation of VR in LTCFs faces many challenges. LTCF residents must gain trust in VR technologies, care providers require training to maximize the positive effects of VRT, and decision makers must evaluate both the opportunities and obstacles in adopting VR. In this review article, we concisely discuss the implications of depression related to place attachment in LTCFs, and explore the potential therapeutic applications of VR.

Electrocardiogram Corrected Q-T Interval Predicts Response to Vagus Nerve Stimulation in Depression

INTRODUCTION

Recent studies have revealed a possible link between heart rate variability (HRV) and major depressive disorder (MDD), with decreased HRV in MDD compared with healthy subjects. Corrected Q-T interval (QTc) has been suggested to represent an indirect estimate of HRV, as QTc length is inversely correlated to parasympathetic activity in healthy subjects. This retrospective study assessed the ability of QTc length in predicting response to vagus nerve stimulation (VNS) treatment in refractory depression.

METHODS

We measured QTc length in 19 patients suffering from refractory depression, selected to be implanted with VNS. Correlations were calculated between baseline QTc (preimplantation) and long-term mood response.

RESULTS

Nineteen patients selected for VNS surgery were included in the study. Baseline 28-item Hamilton Depression Rating Scale scores were 28.5 ± 6.8 and decreased to 15.1 ± 9.5 at 12 months and 12.4 ± 10.4 at 24 months post-VNS. Among the 19 patients, 53% (10) were responders and 26% (5) were in remission at 12 months. Pretreatment QTc averaged 425.5 ± 22.0. Patients with longer baseline QTc displayed larger improvement, with a significant correlation between mood and QTc values after 12 months (r(18) = -0.526, P = 0.02) and also after 24 months of VNS therapy (r(17) = -0.573, P = 0.016).

CONCLUSIONS

The presented analysis showed that increased QTc in patients with MDD might be used as a baseline biomarker for depressive episodes that might respond preferentially to VNS. The link between cardiovagal activity in depression and response to VNS treatment requires further investigation in larger cohorts and randomized controlled trials.

Heart Rate Variability after Treatment for Depression in North Korean Defectors

North Korean Defectors (NKDs) are known to experience multiple psychological symptoms such depression and anxiety. Heart rate variability (HRV) has been implicated in various psychiatric disorders, including posttraumatic stress disorder (PTSD) and depression. No studies have prospectively evaluated HRV parameters in NKDs. We recruited 34 NKDs (2 men, 32 women; age range 25-58 years) who were diagnosed with major depressive disorder. We evaluated psychiatric symptoms using the Korean version of the Hamilton Depression Rating Scale (HDRS), Montgomery-Asberg Depression Rating Scale, and PTSD checklist civilian version. We also performed HRV measurements before and after 12 weeks of antidepressant treatment. In the baseline, HDRS item 14 and 15 showed statistically significant positive correlation with LF/HF ratio. At the endpoint, HDRS item 5 and 8 were found to have positive correlations with some HRV parameters. We found that the sum of fatigue-related HDRS symptoms scores (number 7 and 13) showed significant positive correlation with LF. HDRS total scores also showed significant positive correlations with LF and HF. When the severity of depression was decreased and only the PTSD symptoms persisted at the endpoint, the relationships between HRV and clinical measures were more clearly revealed. This study shows the possibility of using HRV as an objective neurobiological index of autonomic nervous system disorder and reaction to stress in NKDs.

Depressive Symptoms are Associated with Heart Rate Variability Independently of Fitness: A Cross-Sectional Study of Patients with Heart Failure

BACKGROUND

Depression is associated with reduced heart rate variability (HRV) in healthy and cardiac samples, which may be accounted for by physical fitness. In a small sample of cardiac patients, activity and fitness levels attenuated the relationship between HRV and depression. In the current study of heart failure (HF) patients, we hypothesized that depressive symptoms and HRV would be inversely related and physical fitness would attenuate this association.

PURPOSE

To determine if previous associations among depressive symptoms, physical fitness, and HRV would replicate in a sample of HF patients.

METHODS

The sample consisted of HF patients (N = 125) aged 68.55 ± 8.92 years, 68.8% male, and 83.2% Caucasian. The study was cross-sectional and a secondary analysis of a nonrandomized clinical trial (Trial Identifier: NCT00871897). Depressive symptoms were evaluated using the Beck Depression Inventory (BDI)-II, fitness with the 2 min step test (2MST), and HRV during a 10 min resting laboratory psychophysiology protocol. The dependent variable in hierarchical linear regressions was the root mean square of successive differences.

RESULTS

Controlling for sex, age, β-blocker use, hypertension, and diabetes, higher BDI-II scores significantly predicted lower HRV, β = -.29, t(92) = -2.79, p < .01. Adding 2MST did not attenuate the relationship in a follow-up regression.

CONCLUSION

Depressive symptoms were associated with lower HRV in HF patients, independent of physical fitness. Given the prevalence of depression and suppressed HRV common among HF patients, interventions addressing depressive symptoms and other predictors of poor outcomes may be warranted.

Emotion Regulation Difficulties Are Not Always Associated With Negative Outcomes on Women: The Buffer Effect of HRV

The Heart Rate Variability (HRV) is regularly associated with depression and trait emotion regulation. However, the interaction between HRV and emotional disturbances is still debated. Only a few studies indicate that HRV moderates the effect of personality traits involved in psychopathological disorders. Since the regulation of emotions is a transdiagnostic factor for most psychological disorders, this study aimed to explore whether HRV moderates the relationship between trait emotion dysregulation and depressive symptoms. We collected data from 148 participants via online questionnaires and HRV measurements at rest. Results show for the 114 female remaining in the study that whereas high emotion regulation difficulties led to higher depressive symptoms severity when resting HRV is low, depressive symptoms remain stable in the same condition but when resting HRV is high. Overall, high resting HRV appears to dampen the consequences of trait emotion regulation difficulties. Further studies are needed to confirm this result, but this suggests that usual response tendencies could be overcome by deactivating or inhibitory processes such as those implied in cognitive flexibility reflected through HRV, according to the neurovisceral integration model.

Taking Systems Medicine to Heart

Systems medicine is a holistic approach to deciphering the complexity of human physiology in health and disease. In essence, a living body is constituted of networks of dynamically interacting units (molecules, cells, organs, etc) that underlie its collective functions. Declining resilience because of aging and other chronic environmental exposures drives the system to transition from a health state to a disease state; these transitions, triggered by acute perturbations or chronic disturbance, manifest as qualitative shifts in the interactions and dynamics of the disease-perturbed networks. Understanding health-to-disease transitions poses a high-dimensional nonlinear reconstruction problem that requires deep understanding of biology and innovation in study design, technology, and data analysis. With a focus on the principles of systems medicine, this Review discusses approaches for deciphering this biological complexity from a novel perspective, namely, understanding how disease-perturbed networks function; their study provides insights into fundamental disease mechanisms. The immediate goals for systems medicine are to identify early transitions to cardiovascular (and other chronic) diseases and to accelerate the translation of new preventive, diagnostic, or therapeutic targets into clinical practice, a critical step in the development of personalized, predictive, preventive, and participatory (P4) medicine.

Psychological and physiological effects of emotion focused training for self-compassion and self-protection

Emotion Focused Training for Self-Compassion and Self-Protection (EFT-SCP) is a novel intervention developed on the basis of the latest findings on self-criticism from Emotion-focused therapy and existing programs designed to cultivate compassion. EFTSCP is designed to encourage participants to cultivate self-compassion and protective anger as a way of reducing selfcriticism. Our goal was to investigate the effect of this group-based intervention on self-criticism, self-protection, and self-compassion. A total of 73 students were assigned to the EFT-SCP intervention (n=19), no-treatment control (n=34) or to an active control group (n=20). The intervention group met weekly for 1.5 hours and were instructed to incorporate EFT-SCP tasks into their daily life for 12 weeks. Whilst the no-treatment group did not undergo an intervention, the active control group completed an adapted expressive writing task once a week. In addition to the assessment of heart rate variability during imagery tasks, participants also completed self-reported measures of self-compassion and self-criticism before and after the intervention. Compared with both control groups, the intervention group showed a significant increase in heart rate variability following EFT-SCP (during self-critical imagery, P=.049; probability of superiority was .63, and during self-compassionate imagery P=.007; probability of superiority was .62, both effect sizes were medium) and significant decreases in selfcriticism (Hated Self P=.017; .34 and Inadequate Self P<.001; .33) and self-uncompassionate responding (P<.001; .39). All three effect sizes were small. Participating in EFT-SCP had a positive effect on psychological and physiological outcomes.

Heart rate variability monitoring for emotion and disorders of emotion

BACKGROUND

Emotion is composed of cognitive processing, physiological response and behavioral reaction. Heart rate variability (HRV) refers to the fluctuations between consecutive heartbeat cycles, and is considered as a non-invasive method for evaluating cardiac autonomic function. HRV analysis plays an important role in emotional study and detection.

OBJECTIVE

In this paper, the physiological foundation of HRV is briefly described, and then the relevant literature relating to HRV-based emotion studies for the performance of HRV in different emotions, emotion recognition, the evaluation of emotional disorders, HRV biofeedback, as well as HRV-based emotion analysis and management enhanced by wearable devices, are reviewed.

SIGNIFICANCE

It is suggested that HRV is an effective tool for the measurement and regulation of emotional response, with a broad application prospect.

Changes in heart rate variability in first-episode drug-naïve adolescents with major depressive disorder: A 12-week prospective study

BACKGROUND

Major depressive disorder (MDD) is a common mental disorder, the onset of which frequently occurs during adolescence. While differences in heart rate variability (HRV) between depressed and healthy participants have previously been observed, results have been inconsistent. This study thus investigated the features of HRV in adolescents with MDD.

METHODS

We recruited first-episode drug-naïve adolescents aged 13-18 years who had been diagnosed with MDD, and healthy age-matched controls. HRV was measured before and after a 12-week antidepressant treatment. We compared HRV measures between patient group and control group. We also tried to find correlation between HRV measures and depression rating scales.

RESULTS

Fifty-seven participants were included (patient group: n = 31; control group: n = 26). The patient group showed a lower normalized high frequency (HF norm), a higher normalized low frequency (LF norm), and a higher LF/HF ratio than did the control group. After treatment, LF was significantly decreased within the patient group compared to baseline. Hamilton Depression Rating Scales and Children's Depression Inventory scores were positively correlated with LF norm and LF/HF ratio, and negatively correlated with HF norm, when included all participants in analysis LIMITATIONS: Sample size of this study was small to assess influences of confounding factors on HRV. And follow up period was relatively short to see impact of pharmacotherapy.

CONCLUSION

An imbalance of the autonomic nervous system might be a meaningful feature of adolescent MDD, and HRV might represent a potential biological marker for pathophysiological changes in MDD.

Association Between Depression, Anxiety, and Antidepressant Use With T-Wave Amplitude and QT-Interval

Objectives: Cardiac repolarization may be affected by psychiatric disorders and/or antidepressant use, but evidence for this is inconclusive. This study examined the relationship between depressive and anxiety disorder and use of antidepressants with T-wave amplitude (TWA) and QT-interval.

Methods: Data was obtained from the Netherlands Study of Depression and Anxiety (n = 1,383). Depression/anxiety was diagnosed with the DSM-IV based Composite International Diagnostic Interview. The use of tricyclic antidepressants (TCAs), selective serotonin and noradrenalin reuptake inhibitors (SNRIs), and selective serotonin reuptake inhibitors (SSRIs) was established. T-wave amplitude and QT-interval corrected for heart rate (QTc) were obtained from an ECG measured in a type II axis configuration.

Results: Compared to controls, persons with depression or anxiety disorders did not show a significantly different TWA (p = 0.58; Cohen's d = 0.046) or QTc (p = 0.48; Cohen's d = −0.057). In spite of known sympathomimetic effects, TCA use (p = 0.26; Cohen's d = −0.162) and SNRI use (p = 0.70; Cohen's d = −0.055) were not significantly associated with a lower TWA. TCA use (p = 0.12; Cohen's d = 0.225) and SNRI use (p = 0.11; Cohen's d = 0.227) were also not significantly associated with a prolonged QTc.

Conclusion: We did not find evidence that either depressive/anxiety disorder or antidepressant use is associated with abnormalities in TWA or QTc. Earlier found sympathomimetic effects of TCAs and SNRIs are not evident in these measures of cardiac repolarization.

DSM-5 Criteria and Depression Severity: Implications for Clinical Practice

Background: Depression diagnosis requires five or more symptoms (Diagnostic and Statistical Manual of Mental Disorders-DSM-5). One of them must be either Depressed mood or Anhedonia, named main criteria. Although the secondary symptoms can be divided into somatic and non-somatic clusters, the DSM-5 identify depression in all or none fashion. In contrast, depression severity is a continuous variable. Therefore, it is commonly assessed with scales such as the Hamilton Depression Rating Scale (HAMD). Previously, we reported that patients with moderate depression (MD) exhibit greater impairments in cardiac-autonomic modulation than severely depressed (SD) patients. However, clinicians usually do not use scales. Objective: To verify whether the DSM-5 symptoms would be able to discriminate SD from MD and MD from non-depressed (ND) subjects. Material and Methods: Depression was diagnosed based on the Structured Clinical Interview for DSM-5® Disorders. The HAMD evaluated depression severity. In depressed subjects, MD and SD were defined considering the HAMD scores. ND was defined considering both the absence of DSM-5 criteria for depression and the HAMD score. Among 782 outpatients, 46 SD were found. MD and ND subjects were randomly sampled to match the demographic variables of the SD group. Results: Discriminant analysis showed that Depressed Mood was the most reliable symptom to discriminate ND from MD. Anhedonia discriminated SD from MD. Among the secondary DSM-5 criteria, the somatic cluster discriminated ND from MD and the non-somatic cluster SD from MD patients. Discussion: The presence of the somatic cluster in MD may indicate decreased vagal tone and/or increased sympathetic tone, leading to higher cardiovascular risk. As SD is associated with the non-somatic cluster, these patients are at risk of committing suicide. The DSM-5 symptoms exhibited by the patient may help the choice of adequate pharmacological treatment. This would avoid the use of antidepressants that unnecessarily increase cardiac risk in MD. When the symptom cluster suggests SD, the treatment must focus on the prevention of suicide. Conclusions: Depression severity may be inferred based on the DSM-5 criteria. The presence of the Anhedonia main criterium accompanied by non-somatic criteria indicate SD. The Depressive Mood criterium followed by somatic criteria suggest MD.