Peak High-Frequency HRV and Peak Alpha Frequency Higher in PTSD

Posttraumatic stress disorder (PTSD) is difficult to treat and current PTSD treatments are not effective for all people. Despite limited evidence for its efficacy, some clinicians have implemented biofeedback for PTSD treatment. As a first step in constructing an effective biofeedback treatment program, we assessed respiration, electroencephalography (EEG) and heart rate variability (HRV) as potential biofeedback parameters for a future clinical trial. This cross-sectional study included 86 veterans; 59 with and 27 without PTSD. Data were collected on EEG measures, HRV, and respiration rate during an attentive resting state. Measures were analyzed to assess sensitivity to PTSD status and the relationship to PTSD symptoms. Peak alpha frequency was higher in the PTSD group (F(1,84) = 6.14, p = 0.01). Peak high-frequency HRV was lower in the PTSD group (F(2,78) = 26.5, p < 0.00005) when adjusting for respiration rate. All other EEG and HRV measures and respiration were not different between groups. Peak high-frequency HRV and peak alpha frequency are sensitive to PTSD status and may be potential biofeedback parameters for future PTSD clinical trials.     

The Effects of Respiratory Sinus Arrhythmia Biofeedback on Heart Rate Variability and Posttraumatic Stress Disorder Symptoms: A Pilot Study

Recent studies have found a significant association between PTSD and low heart rate variability (HRV), a biomarker of autonomic dysregulation. Research indicates that respiratory sinus arrhythmia (RSA) biofeedback increases HRV while reducing related pathological symptoms. This controlled pilot study compared RSA biofeedback to progressive muscle relaxation (PMR) as adjunctive interventions for 38 persons with PTSD symptoms in a residential treatment facility for a substance use disorder. Both groups were assessed at pre-intervention and 4-week post-intervention. Group × time interactions revealed significantly greater reductions in depressive symptoms and increases in HRV indices for the RSA group. Both groups significantly reduced PTSD and insomnia symptoms and a statistical trend was observed for reduced substance craving for the RSA group. Increases in HRV were significantly associated with PTSD symptom reduction. Overall, these results provide preliminary support for the efficacy of RSA biofeedback in improving physiological and psychological health for individuals with PTSD.     

Use of a Portable Biofeedback Device to Improve Insomnia in a Combat Zone,a Case Report

Insomnia is a common problem in situations of stress. Some forms of stress, however, may contraindicate the use of traditional, pharmacological interventions. Working in a combat zone is such a situation. Alternative means of improving sleep are clearly needed for Service Members. We report a case involving a medical provider who was serving in a military, emergency-services facility in Iraq, and who presented with anxiety, depressed mood, and insomnia. Symptoms were sub-threshold for major depressive disorder or acute stress disorder. Mood and anxiety symptoms responded to traditional therapy techniques, but problems with insomnia remained. The patient was given a portable biofeedback device that employs an infrared sensor photoplethysmograph to measure heart rate variability (HRV) from peripheral finger pulse. One week later, sleep was significantly improved. Symptom improvement lasted to at least 6 weeks while in theater. One year later, a check-in with the patient revealed that after returning home, he had been diagnosed with post traumatic stress disorder (PTSD). PTSD symptoms had resolved after 6 months of psychopharmacology and cognitive behavioral therapy. These results indicate that biofeedback may be a useful means of improving sleep in a combat zone, but that such improvements may not necessarily prevent the development of more serious symptoms later. No clear causality can be inferred from a single case, and further study is needed to determine if this finding have wider applicability.     

A Pilot Study of Brief Heart Rate Variability Biofeedback to Reduce Craving in Young Adult Men Receiving Inpatient Treatment for Substance Use Disorders

The present pilot study investigated the implementation feasibility, and efficacy for reducing alcohol and drug craving, of a brief, 3-session heart rate variability biofeedback (HRV BFB) intervention added to a traditional 28-day substance abuse disorder inpatient treatment program. Forty-eight young adult men received either treatment as usual (TAU) plus three sessions of HRV BFB training over 3 weeks, or TAU only. Participants receiving HRV BFB training were instructed to practice daily using a hand-held HRV BFB device. HRV BFB training was well tolerated by participants and supported by treatment staff. Men receiving TAU + HRV BFB demonstrated a greater, medium effect size reduction in alcohol and drug craving compared to those receiving TAU only, although this difference did not reach statistical significance. In addition, an interaction effect was observed in analyses that accounted for baseline craving levels, wherein heart rate variability (HRV) levels at treatment entry were predictive of changes in craving in the TAU group only. Low baseline levels of HRV were associated with increases in craving, whereas higher baseline HRV levels were associated with greater decreases in craving from start to end of treatment. In the TAU + HRV BFB group, however, there was no such association. That is, HRV BFB appeared to dissociate individual differences in baseline HRV levels from changes in craving. Given that alcohol and drug craving often precipitates relapse, HRV BFB merits further study as an adjunct treatment to ameliorate craving experienced by persons with substance use disorders.     

A randomized controlled effectiveness trial of cognitive behavior therapy for post-traumatic stress disorder in terrorist-affected people in Thailand

Although cognitive behaviour therapy (CBT) is the treatment of choice for post-traumatic stress disorder (PTSD), there is no evidence of its success with PTSD patients still under direct threat of terrorist attacks. This study reports the first randomized controlled trial of CBT for PTSD terrorist-affected people. Twenty-eight survivors of terrorist attacks in southern Thailand were randomized to 8 sessions of either CBT or treatment as usual (TAU). CBT was modified to accommodate the realistic threats facing patients. There were independent assessments conducted before, immediately after, and 3 months following treatment. Main outcome measures included symptoms of PTSD (PTSD Symptom Scale Interview), depression (Beck Depression Inventory) and complicated grief (Inventory of Complicated Grief). CBT resulted in significantly greater reduction in symptoms, including PTSD, depression, and complicated grief, at follow-up than TAU. Relative to TAU, CBT had stronger effect sizes at follow-up for PTSD, depression, and complicated grief. More patients in the CBT condition (75%) achieved high end-state functioning than participants in the TAU (33%). This preliminary evidence suggests that PTSD, depression, and complicated grief can be effectively treated despite ongoing threats of terrorism. Further, it demonstrates that non-specialist mental health workers in a non-western setting can be efficiently trained in using CBT, and this training can translate into successful treatment gains in trauma-affected individuals.     

Restoration of Vagal Tone: A Possible Mechanism for Functional Abdominal Pain

Functional abdominal pain (FAP) causes disruption of daily activities/missed school days, over utilization of healthcare, unnecessary surgeries, and anxiety in 10–15% of children. Its etiology is not clearly understood, however the success of several clinical protocols suggests that autonomic dysregulation is a factor. In this study autonomic activity, including heart rate variability (HRV), was compared between children with FAP and a comparison group. Twenty children with FAP and 10 children without FAP between the ages of 5 and 17 years old were compared on autonomic regulation using an ambulatory system at baseline and 8 weeks later. Children with FAP participated in 6 sessions of HRV biofeedback aimed at normalizing autonomic balance. At baseline, children with FAP appear to have more autonomic dysregulation than children without FAP. After completing HRV biofeedback, the FAP group was able to significantly reduce their symptoms in relation to significantly increasing their autonomic balance. In a sample of children with FAP, it appears that HRV biofeedback treatment improved their symptoms and that a change in vagal tone was a potential mediator for this improvement. The present study appears to point to excessive vagal withdrawal as an underlying mechanism of FAP.     

Use of Paced Respiration to Alleviate Intractable Hiccups (Singultus): A Case Report

Heart rate variability (HRV) biofeedback is an emerging treatment for many health conditions involving dysregulation of the autonomic nervous system including hypertension, gastric pain, anxiety, and depression. Hiccups are frequently considered an annoyance. However, when intractable (lasting over 1 month), they can become debilitating, with some patients resorting to invasive treatments that often involve the phrenic nerve. Theoretically, HRV biofeedback should also provide a means to stimulate the phrenic nerve and could be an alternative option. We report the successful treatment of a 5 year-long case of intractable hiccups with one session of HRV biofeedback training. These results suggest that biofeedback may be a useful, non-invasive means of relieving intractable hiccups. No clear causality can be inferred from a single case, and further study is needed to determine if this finding has wider applicability.     

Systematic Review of Biofeedback Interventions for Addressing Anxiety and Depression in Children and Adolescents with Long-Term Physical Conditions

Children and adolescents with long-term physical conditions are at increased risk of psychological problems, particularly anxiety and depression, and they have limited access to evidence-based treatment for these issues. Biofeedback interventions may be useful for treating symptoms of both psychological and physical conditions. A systematic review of studies of biofeedback interventions that addressed anxiety or depression in this population was undertaken via MEDLINE, EMBASE, PsycINFO, CINAHL and the Cochrane Central Register of Controlled Trials databases. Primary outcomes included changes in anxiety and depression symptoms and ‘caseness’. Secondary outcomes included changes in symptoms of the associated physical condition and acceptability of the biofeedback intervention. Of 1876 identified citations, 9 studies (4 RCTs, 5 non-RCTs; of which all measured changes in anxiety and 3 of which measured changes in depression) were included in the final analysis and involved participants aged 8–25 years with a range of long-term physical conditions. Due to the heterogeneity of study design and reporting, risk of bias was judged as unclear for all studies and meta-analysis of findings was not undertaken. Within the identified sample, multiple modalities of biofeedback including heart rate variability (HRV), biofeedback assisted relaxation therapy and electroencephalography were found to be effective in reducing symptoms of anxiety. HRV was also found to be effective in reducing symptoms of depression in two studies. A range of modalities was effective in improving symptoms of long-term physical conditions. Two studies that assessed acceptability provided generally positive feedback. There is currently limited evidence to support the use of biofeedback interventions for addressing anxiety and depression in children and adolescents with long-term physical conditions. Although promising, further research using more stringent methodology and reporting is required before biofeedback interventions can be recommended for clinical use instead or in addition to existing evidence-based modalities of treatment.     

A Pilot Study on the Effects of Heart Rate Variability Biofeedback in Patients with Depression and in Healthy Subjects

Decreased vagal activity and increased sympathetic arousal have been proposed as major contributors to the increased risk of cardiovascular mortality in patients with depression. It was aim of the present study to assess the feasibility of using heart rate variability (HRV) biofeedback to treat moderate to severe depression. This was an open-label study in which 14 patients with different degrees of depression (13 f, 1 m) aged 30 years (18–47; median; range) and 12 healthy volunteers attended 6 sessions of HRV biofeedback over two weeks. Another 12 healthy subjects were observed under an active control condition. At follow up BDI was found significantly decreased (BDI 6; 2–20; median 25%–75% quartile) as compared to baseline conditions (BDI 22;15–29) in patients with depression. In addition, depressed patients had reduced anxiety, decreased heart rate and increased HRV after conduction of biofeedback (p < 0.05). By contrast, no changes were noted in healthy subjects receiving biofeedback nor in normal controls. In conclusion, HRV biofeedback appears to be a useful adjunct for the treatment of depression, associated with increases in HRV.     

Effects of Pharmacotherapy on Combat-Related PTSD,Anxiety, and Depression: A Systematic Review and Meta-Regression Analysis

ObjectivesTo estimate the effect of pharmacotherapy on PTSD, anxiety, and depression among combat veterans; to determine whether the effects varied according to patient and intervention characteristics; and to examine differential effects of pharmacotherapy on outcomes.ResultsPharmacotherapy significantly reduced (Δ, 95%CI) PTSD (0.38, 0.23-0.52), anxiety (0.42, 0.30-0.54), and depressive symptoms (0.52, 0.35-0.70). The effects of SSRIs and tricyclic antidepressants on PTSD were greater than other medications independent of treatment duration. The effect of SSRIs and tricyclic antidepressants were greater than other medications up to 5.2 and 13.6 weeks for anxiety and depression, respectively. The magnitude of the effect of pharmacotherapy on concurrently-measured PTSD, anxiety, and depression did not significantly differ.ConclusionsPharmacotherapy reduced PTSD, anxiety, and depressive symptoms in combat veterans. The effects of SSRIs and tricyclic antidepressants were greater for PTSD and occurred quicker for anxiety and depression than other medications.     

Social support and posttraumatic stress disorder in combat veterans in Croatia

Recent studies have shown that greater social support after combat stress is associated with better psychological posttraumatic outcomes. By comparison of a group of veterans (n = 71) who sought psychiatric help and were diagnosed with PTSD (clinical group) and a group of veterans (n = 43) without PTSD (control group) we examined various components of structural and functional social support in war veterans in Croatia. The measures of social support were assessed for two time periods: a) immediately after the war, and b) at the present time. Results of two-way analysis of variance indicate that veterans without PTSD tend to report significantly higher number of persons who provide them different forms of social support than veterans with PTSD. Perceived family and friends support is higher in veterans without PTSD than in veterans with PTSD. Support received from friends and fellow soldiers decreases over time in both groups, whereas for the clinical group support of friends decreases significantly more.     

Effectiveness of emWave Biofeedback in Improving Heart Rate Variability Reactivity to and Recovery from Stress

The current study examined the efficacy of heart rate variability (HRV) biofeedback using emWave, a publicly available biofeedback device, to determine whether training affected physiological tone and stress responses. Twenty-seven individuals aged 18–30 years were randomized to a treatment or no-treatment control group. Treatment participants underwent 4–8 sessions of emWave intervention, and all participants attended pre-treatment and post-treatment assessment sessions during which acute stressors were administered. Physiological data were collected at rest, during stress, and following stress. emWave treatment did not confer changes in tonic measures of HRV or in HRV recovery following stress. However, treatment participants exhibited higher parasympathetic responses (i.e., pNN50) during stress presentations at the post-treatment session than their control counterparts. No treatment effects were evident on self-reported measures of stress, psychological symptoms, or affect. Overall, results from the current study suggest that the emWave may confer some limited treatment effects by increasing HRV during exposure to stress. Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in clinical settings, including the determination of what physiological changes are clinically meaningful during HRV biofeedback training.     

An Exploratory Analysis of the Utility of Adding Cardiorespiratory Biofeedback in the Standard Care of Pregnancy-Induced Hypertension

This study examined the efficacy of a cardiorespiratory biofeedback intervention compared to bed rest in the treatment of 47 women diagnosed with pregnancy-induced hypertension (PIH). The investigation consisted of a historical control group with 31 PIH subjects receiving treatment as usual (TAU), bed rest and antihypertensive medications, and an experimental group with 16 PIH subjects receiving TAU and instruction on using a portable respiratory sinus arrhythmia (RSA) biofeedback device once daily until delivery. Results indicated that systolic and diastolic blood pressure levels were unchanged for either group. Failing to find the intended main effects, a series of exploratory analyses were performed. Findings of associated hypotheses revealed that the RSA BF group had a 35 % higher birth weight than the TAU group. The gestational age at delivery was 10 % greater in the RSA BF group than in the TAU group. A significant relationship was found between the StressEraser Total and the 1-min Apgar score. Eighty-one percent of the subjects stated that the device was relaxing. Fifty percent of the subjects believed that the device helped them fall asleep. Overall, these results suggest that portable RSA biofeedback may be effective in reducing stress during pregnancy and improving perinatal outcomes.     

A Pilot Study of the Efficacy of Heart Rate Variability (HRV) Biofeedback in Patients with Fibromyalgia

Fibromyalgia (FM) is a non-inflammatory rheumatologic disorder characterized by musculoskeletal pain, fatigue, depression, cognitive dysfunction and sleep disturbance. Research suggests that autonomic dysfunction may account for some of the symptomatology of FM. An open label trial of biofeedback training was conducted to manipulate suboptimal heart rate variability (HRV), a key marker of autonomic dysfunction. Methods: Twelve women ages 18–60 with FM completed 10 weekly sessions of HRV biofeedback. They were taught to breathe at their resonant frequency (RF) and asked to practice twice daily. At sessions 1, 10 and 3-month follow-up, physiological and questionnaire data were collected. Results: There were clinically significant decreases in depression and pain and improvement in functioning from Session 1 to a 3-month follow-up. For depression, the improvement occurred by Session 10. HRV and blood pressure variability (BPV) increased during biofeedback tasks. HRV increased from Sessions 1–10, while BPV decreased from Session 1 to the 3 month follow-up. Conclusions: These data suggest that HRV biofeedback may be a useful treatment for FM, perhaps mediated by autonomic changes. While HRV effects were immediate, blood pressure, baroreflex, and therapeutic effects were delayed. This is consistent with data on the relationship among stress, HPA axis activity, and brain function.     

Social rhythm regularity moderates the relationship between sleep disruption and depressive symptoms in veterans with post-traumatic stress disorder and major depressive disorder

ABSTRACT

Approximately 50% to 80% of individuals with posttraumatic stress disorder (PTSD) also meet criteria for major depressive disorder (MDD). Sleep disturbance is a major concern in both PTSD and MDD, and is associated with poor treatment response, poor functional outcome and increased suicide risk. Social rhythm regularity, or the consistency of daily habitual behaviors, is theoretically linked to circadian rhythms and may be disturbed in both PTSD and MDD. The present study examined the relationship between social rhythm regularity, sleep disruption and MDD and PTSD symptoms in a sample of veterans with comorbid PTSD and MDD. Baseline data were obtained from 56 male veterans who met DSM-IV criteria for PTSD and MDD. Veterans completed the Social Rhythm Metric (SRM), a self-report questionnaire that assesses the regularity of routines by determining how regularly individuals completed 17 different types of activities. In a linear regression model, increased minutes awake after sleep onset (WASO) was a significant predictor of increased depression scores on the Hamilton Rating Scale for Depression (p < .05). SRM scores did not significantly predict depressive symptoms, however the interaction of WASO and SRM significantly predicted depressive symptoms (p = <.05), with significant relationships found at SRM scores less than 3.62. Neither minutes awake after sleep onset, SRM scores, nor their interaction was associated with PTSD symptom severity. Social and possibly circadian rhythm regularity may represent a risk or resilience factor for individuals with comorbid PTSD and MDD. Findings highlight the importance of exploring the interactions of sleep and social/circadian rhythms in depression in order to inform continued treatment development.     

Effect of voluntary EEG α power increase training on heart rate variability

The following objectives were set out to study the effect of EEG α power increase training on the heart rate variability (HRV) as an index of the autonomic regulation of cognitive functions: (1) to establish the interrelation between a voluntary increase in the α power in the individual upper α band and the HRV and related characteristics of cognitive and emotional spheres; (2) to determine the nature of the relationship between the α-activity indices and HRV depending on the resting α-frequency EEG pattern; and (3) to study how the individual α-frequency EEG pattern is reflected in the HRV changes as a result of biofeedback training. Psychometric indices of cognitive performance and the characteristics of EEG α activity and HRV were recorded in 27 healthy men 18–34 years of age before, during, and after ten training sessions of a voluntary increase in α power in the individual upper α band with the eyes closed. To determine the biofeedback effect in the α power increase training, the data of two groups were compared: the experimental, with a real biofeedback (14 subjects), and the control, with a sham biofeedback (13 subjects). The follow-up effect of the training was assessed one month after its end. The results showed that α biofeedback training increased the resting α frequency, improved cognitive performance, reduced psychoemotional stress, and increased HRV only in the subjects with a low baseline α frequency. In the subjects with a high baseline resting α frequency, the α biofeedback training had no effect on the resting α power and cognitive performance but reduced the HRV (judging by the pNN ₅₀ parameter). The positive correlation between the α peak frequency and HRV in subjects with initially low α frequency and the negative correlation in the subjects with a high baseline α frequency explains the opposite biofeedback effects on HRV in subjects with low and high α frequency. From the theoretical standpoint, the results of this study contribute to understanding the mechanisms of heart-brain neurovisceral relationships and their effect on the cognitive performance. From the applied standpoint, they suggest that EEG biofeedback can be used for improving autonomic regulation in healthy subjects and the development of individual approaches to the development of the biofeedback technology, which can be used both in clinical practice for treatment and rehabilitation of psychosomatic syndromes and in educational training.     

Matter Over Mind: A Randomised-Controlled Trial of Single-Session Biofeedback Training on Performance Anxiety and Heart Rate Variability in Musicians

Background

Musical performance is a skilled activity performed under intense pressure, thus is often a profound source of anxiety. In other contexts, anxiety and its concomitant symptoms of sympathetic nervous system arousal have been successfully ameliorated with HRV biofeedback (HRV BF), a technique involving slow breathing which augments autonomic and emotional regulatory capacity. Objective: This randomised-controlled study explored the impact of a single 30-minute session of HRV BF on anxiety in response to a highly stressful music performance.

Methods

A total of 46 trained musicians participated in this study and were randomly allocated to a slow breathing with or without biofeedback or no-treatment control group. A 3 Group×2 Time mixed experimental design was employed to compare the effect of group before and after intervention on performance anxiety (STAI-S) and frequency domain measures of HRV.

Results

Slow breathing groups (n = 30) showed significantly greater improvements in high frequency (HF) and LF/HF ratio measures of HRV relative to control (n = 15) during 5 minute recordings of performance anticipation following the intervention (effect size: η² = 0.122 and η² = 0.116, respectively). The addition of biofeedback to a slow breathing protocol did not produce differential results. While intervention groups did not exhibit an overall reduction in self-reported anxiety, participants with high baseline anxiety who received the intervention (n = 15) displayed greater reductions in self-reported state anxiety relative to those in the control condition (n = 7) (r = 0.379).

Conclusions

These findings indicate that a single session of slow breathing, regardless of biofeedback, is sufficient for controlling physiological arousal in anticipation of psychosocial stress associated with music performance and that slow breathing is particularly helpful for musicians with high levels of anxiety. Future research is needed to further examine the effects of HRV BF as a low-cost, non-pharmacological treatment for music performance anxiety.     

The Effect of Biofeedback on Function in Patients with Heart Failure

Decreased HRV has been consistently associated with increased cardiac mortality and morbidity in HF patients. The aim of this study is to determine if a 6-week course of heart rate variability (HRV) biofeedback and breathing retraining could increase exercise tolerance, HRV, and quality of life in patients with New York Heart Association Class I-III heart failure (HF). Participants (N = 29) were randomly assigned to either the treatment group consisting of six sessions of breathing retraining, HRV biofeedback and daily practice, or the comparison group consisting of six sessions of quasi-false alpha-theta biofeedback and daily practice. Exercise tolerance, measured by the 6-min walk test (6MWT), HRV, measured by the standard deviation of normal of normal beats (SDNN), and quality of life, measured by the Minnesota Living with Congestive Heart Failure Questionnaire, were measured baseline (week 0), post (week 6), and follow-up (week 18). Cardiorespiratory biofeedback significantly increased exercise tolerance (p = .05) for the treatment group in the high (≥31%) left ventricular ejection fraction (LVEF) category between baseline and follow-up. Neither a significant difference in SDNN (p = .09) nor quality of life (p = .08), was found between baseline and follow-up. A combination of HRV biofeedback and breathing retraining may improve exercise tolerance in patients with HF with an LVEF of 31% or higher. Because exercise tolerance is considered a strong prognostic indicator, cardiorespiratory biofeedback has the potential to improve cardiac mortality and morbidity in HF patients.

Resting Heart Rate Variability and the Effects of Biofeedback Intervention in Women with Low-Risk Pregnancy and Prenatal Childbirth Fear

Anxiety about labor in women at the end of pregnancy sometimes reaches levels that are clinically concerning. We investigated whether low-risk pregnant women with childbirth fear during the last trimester demonstrate specific findings with regard to resting heart rate variability (HRV) and examined whether HRV biofeedback can reduce this fear and alter resting HRV. We measured the levels of childbirth fear (Wijma delivery expectancy/experience questionnaire, W-DEQ) and resting HRV indexes in 97 low-risk pregnant women in their 32nd–34th week of gestation and advised women with W-DEQ scores of ≥?66 (n?=?40) to practice HRV biofeedback (StressEraser) at home. We then reassessed these measures 3–4 weeks later in the 36th–37th week of gestation regardless of whether the women practiced the method. We found that childbirth fear had no significant effect on resting HRV indexes when the W-DEQ cutoff was conventionally set at ≥?66. However, women with W-DEQ scores of ≥?90 (n?=?5) had a significantly lower high-frequency power than their counterparts (p?=?0.028). The W-DEQ scores reduced significantly in women who performed HRV biofeedback (n?=?18, p?<?0.001), but there was no change in those who did not perform the method (n?=?20). These findings suggested that very high W-DEQ scores (≥?90), but not the conventional criteria (W-DEQ score?≥?66), of the fear of childbirth were associated with low parasympathetic activity among low-risk pregnant women and that HRV biofeedback intervention can effectively decrease the fear of childbirth in these women.     

Correlation of sleep disturbances, anxiety and depression in Croatian war veterans with posttraumatic stress disorder

The aim of the study was to examine the relationships between global sleep quality and its specific components and Posttraumatic Stress Disorder (PTSD) symptom severity questionnaire. We also researched whether sleep quality and sleep disturbances differed among groups of PTSD based on symptom severity categories. This study was conducted on the sample of 120 Croatian war veterans with PTSD. The following self-report instruments were used: Pittsburgh Sleep Quality Index, the Pittsburgh Sleep Quality Index Addendum for PTSD, the Mississippi Scale for Combat-Related PTSD, the Spielberger State and Trait Anxiety Inventory and the Beck Depression Inventory. There were statistically significant differences between the three PTSD severity groups on general nervousness (PSQI-A variable), where patients with extremely severe PTSD have more symptoms of general nervousness than groups with severe or moderate PTSD. Differences were found between PTSD severity groups in episodes of terror and acting-out dreams, where patients with extremely severe PTSD have more symptoms of episodes of terror and acting-out dreams than groups with severe or moderate PTSD. Sleep quality was significantly correlated with state anxiety, trait anxiety, and depression, indicating that with decrease of anxiety and depression, sleep quality improves. Sleep latency was positively correlated with both state and trait anxiety. There wasn't any significant correlation between sleep latency and depression. Study suggests that sleep disturbances are equally severe across groups of veterans based on PTSD severity and that the severity of sleep disturbances is significantly related to severity of anxiety and depression symptoms.