Clinical importance of nightmare disorder in patients with dissociative disorders

Authors


Dr Mehmet Yucel Agargun, Yuzuncu Yil University School of Medicine, Department of Psychiatry and Neuroscience Research Unit, Van 65200, Turkey. Email: myagargun@kure.com.tr

Abstract

Abstract  In the present study the prevalence of nightmare disorder (ND) was examined in patients with dissociative disorders (DD), and comparison was made between those with ND and those without nightmares in terms of clinical characteristics. The 30 patients with DD (5 male and 25 female) were recruited over 12 months in the Yüzüncü Yil University Research Hospital Department of Psychiatry. The subjects were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (4th edn) criteria for ND. The Dissociative Experiences Scale, Beck Depression Inventory, and a semistructured interview schedule for childhood traumatic events were administered to the subjects. A 57% prevalence of ND was found among patients with DD. Among patients with DD, those with ND had a higher rate of self-mutilative behavior, a history of suicide attempt in the last year, and comorbidity with borderline personality disorder than those without ND. Nightmares or dreams should be considered in the therapy of DD patients.

INTRODUCTION

Nightmares are long frightening dreams involving threats to survival or security, from which the sleeper awakens, and should be distinguished from sleep terrors, narcolepsy, sleep panic attacks, and other awakenings. Nightmares typically occur later in the night during rapid eye movement (REM) sleep and produce vivid dream imagery, complete awakenings, autonomic arousal, and detailed recall of the event and may cause psychological distress and social or occupational dysfunction. Although lifetime prevalence for a nightmare experience in the general population is unknown, there is a significant increase in prevalence of nightmares during the developmental course from childhood to adult life.1

Recurrent nightmares may be associated with a high comorbidity of mood and anxiety disorder, in particular in young adults and adults. Interestingly, in depressive patients, nightmares often occur during the illness and dramatically decrease in the treatment period. Moreover, a significant association between repetitive and frightening dreams and suicidal tendency was found in patients with major depression in a recent study.2 Nightmares were also reported to be associated with personality disorders,3 schizotipy,4 alexithymia5 and drug and alcohol dependence,6 and acute and post-traumatic stress disorders.7 The association of dream disturbances with flashbacks related to the trauma suggests that nightmares appear to be an effective coping mechanism in trauma victims.7

Recently, we suggested an association between nightmares and dissociative states or experiences.8 We examined the relationship of nightmares to dissociative experiences in a large group of adolescents. We demonstrated a relationship between dream anxiety and dissociative experiences and the causal role of childhood traumatic events in this relationship. In the present study, we examined prevalence of nightmare disorder (ND) in patients with dissociative disorders (DD), and compared those with ND with those without nightmares in terms of clinical characteristics including depression, borderline personality disorder, suicide attempts, self-mutilative behavior, and the history of childhood traumatic events.

METHODS

Subjects

We recruited patients over 12 months in the Yüzüncü Yil University Research Hospital Department of Psychiatry. The 30 patients with DD (5 male and 25 females) participated in the study. The subjects were interviewed using Structured Clinical Interview for Dissociative Disorders (SCID-D).9 All subjects gave written informed consent prior to their participation in the study. Subjects with organic mental disorders, mental retardation, alcohol and substance abuse, psychotic disorders, and mood disorders were not included in the study.

Instruments

We used Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM-IV) diagnostic criteria for ND,10 as follows.

(1) ‘Repeated awaking from the major sleep period or naps with detailed recall of extended and extremely frightening dreams, usually involving threats to survival, security, or self-esteem. The awakening generally occurs during the second half of the sleep period’ (criterion A).

(2) ‘On awakening from the frightening dreams, the person rapidly becomes oriented and alert (in contrast to the confusion and disorientation seen in sleep terror and some forms of epilepsy)’ (criterion B).

(3) ‘The dream experience, or sleep disturbance resulting from the awakening, causes clinically significant distress or impairment in social, occupational, or other important areas of functioning’ (criterion C).

(4) ‘Do not occur exclusively in the course of another mental disorder and are not due to the direct physiological effects of a substance or a general medical population’ (criterion D).

According to these criteria we also diagnosed 17 patients (57%; 3 male, 14 female) as having ND. The remaining 13 patients (2 male, 11 female) were not classified as having ND.

The subjects were also interviewed for childhood traumatic events including childhood physical or sexual abuse, maternal loss, and maternal separation. Characteristics of childhood physical and sexual abuse were obtained from a structured life-events interview. As part of our structured interview, subjects were queried about their childhood relationships with parents, relatives and others. We defined physical abuse as threatened, attempted, or actual infliction of physical harm and defined sexual abuse as threatened, attempted, or actual infliction of sexual harm. Severity of physical and sexual abuse was categorized into three levels: mild, moderate, and severe. Mild abuse was characterized as the subjects’ experience or fear of being: pushed, grabbed, or shoved; kicked, bitten, or punched; spanked; choked or burned; hit by an object or individual; physically attacked in any other way; or fear of witnessing other people experience any type of abuse, with a frequency of a few times or less, or being spanked more than a few times. Moderate abuse was defined as the subjects’ experience or fear of all types of mild abuse (apart from being spanked) with a frequency of more than a few times, or of being the victim of sexual exposure a few times or less. We defined severe abuse as the subjects’ experience or fear of: being choked or burned; being physically attacked in any other way; being the victim of sexual exposure more than a few times; or that someone would sexually assault them, be sexual with them against their will, or kill someone they loved, at any frequency. The methodology was similar to two previous studies.8,11 All subjects whose abuse was described as mild, moderate or severe were included in the study.

Dissociative Experiences Scale

The Dissociative Experiences Scale (DES) was administered to all subjects. The DES was developed by Bernstein and Putnam.12 The DES is a 28-item self-report instrument that can be completed in 10 min and scored in less than 5 min. It is easy to understand and the questions are framed in a normative way that does not stigmatize the respondent for positive responses. The respondent then slashes the line, which is anchored at 0% on the left and 100% on the right, to show how often he or she has this experience. The overall DES score is obtained by adding up the 28 item scores and dividing by 28; this yields an overall score ranging from 0 to 100. The scale contains a variety of dissociative experiences, many of which are normal experiences. The DES has very good validity and reliability, and good overall psychometric properties. The Turkish version of the scale has a reliability and validity13 as high as its original form.

Beck Depression Inventory

The Beck Depression Inventory (BDI)14 was used to assess severity of depressive symptoms in the subjects.

Statistical analyses

Comparisons of clinical characteristics and the scale scores  were  compared  using  the  χ2 test  and  Student's t-test. Analyses were performed the statistical package for the social sciences (SPSS) for Windows ver. 9.01.

RESULTS

Clinical characteristics of the patients are shown in Tables 1 and 2. As shown, there was no difference between groups in the history of childhood traumatic events. The patients with ND also had a higher rate of self-mutilative behavior, a history of suicide attempt in the last year, and a diagnosis of borderline personality disorder than those without ND (χ2 = 6.11, P = 0.013; χ2 = 4.47, P = 0.034; and χ2 = 3.75, P = 0.05, respectively). The groups of patients were not different from each other in terms of age, age at onset, and BDI and DES scores.

Table 1.  Clinical characteristics of DD patients with and without ND
 Patients with
ND (n = 17)
Patients without
ND (n = 13)
χ2P
  1. DD, dissociative disorders; ND, nightmare disorder; NS, not significant.

Sexual abuse1290.06NS
Physical abuse 220.08NS
Parental loss 110.04NS
Self-mutilative behavior1456.110.013
Suicide 924.470.034
Depression 831.820.17
Borderline personality disorder 823.750.05
Table 2.  More clinical characteristics of DD patients with and without ND
 Patients with
ND (n = 17)
Patients without
ND (n = 13)
tP
  1. DD, dissociative disorders; ND, nightmare disorder; NS, not significant; DES, Dissociative Experiences Scale; BDI, Beck Depression Inventory.

Age (years)23.4 ± 5.822.5 ± 5.10.45NS
Onset age
(years)
19.4 ± 4.618.4 ± 4.90.54NS
DES48.8 ± 20.536.5 ± 18.91.28NS
BDI29.7 ± 12.632.6 ± 10.50.37NS

DISCUSSION

We examined the frequency of ND in patients with DD, and compared those patients with ND also with those without nightmares in terms of presence of depression, borderline personality disorder, suicide attempts, self-mutilative behavior, and the history of childhood traumatic events. We found a 57% prevalence of ND among patients with DD. This shows that more than half of DD patients are also diagnosed as having ND. This is the first study, to our knowledge, that examines frequency of ND in these patients. In a recent study our group examined the co-occurrence of nightmares with dissociative experiences in an adolescent population.8 The Van Dream Anxiety Scale (VDAS)15 and DES were administered to 292 college students. We found a 7.5% prevalence of ‘often’ nightmares ‘and a 58.2% prevalence of ‘sometimes’ nightmares in this sample. Nightmare prevalence was higher in female than in male subjects. In addition, the mean DES scores of the subjects with nightmares was higher than those who never reported nightmares. The present study, together with the previous study, suggests that nightmares are associated with dissociative experiences or DD.

There is no systematic study that examines dream characteristics of patients with DD in the sleep laboratory in the literature. A recent study examined dreams in dissociative disorders using dream questionnaire.16 In that study it was reported that DD persons experience much more of a dreamlike state in their waking life. In a recent study, Cartwright et al. suggested that dreaming patterns occurred depending on waking personality variables such as differences in defense styles.17 Their findings were supportive of there being individual differences in an ability to form dreams that connect present affect related to a disturbing event, to other  images.  A  high  level  of  this  ability  is  predictive of improvement in waking functioning. Moreover, dreams may possibly be thought of as dissociative phenomena of a particular type that reflect a monitoring of and reaction to internal and external conditions within the dreamer.18 In our previous study we discussed neuroanatomic correlates of underlying mechanisms of nightmares and dissociative phenomena.8 In summary, neuroanatomic functions in traumatic events are similar to traumatic dreams, particularly amigdala and frontoorbital structures.

In the present study we did not find an association between nightmare disorder and childhood traumatic events. This result is unexpectedly different from our previous results.8 Previously, we found an association among nightmares, dissociative experiences, and a history of childhood physical, psychological, and sexual trauma. We suggested that dreams, particularly those that focus on an emotionally disturbing event, are necessary to emotional adaptation in childhood traumatic events, and nightmares have an adaptive function in this process. However, the subject population consisted of college students in the previous study, while the present study examined a patient population, and this may cause differences in the results. Further studies are needed to show the key role of traumatic childhood events in terms of the relationship between dissociative mechanisms and nightmare disorder.

In the present study, among patients with DD, those with ND also had a higher rate of self-mutilative behavior, a history of suicide attempt in the last year, and comorbidity with borderline personality disorder than those without ND. We have previously suggested a close relationship between violent behavior during sleep or during the day and dissociative phenomena.19 We found that persons with self-mutilating behaviors had higher DES scores than those without. Self-mutilation reflects a pathological dissociation. A high incidence of a variety of self-injury behaviors, including cutting, hitting, burning, stabbing, hair pulling, and neurotic excoriations was reported among persons with DD.20 In addition to daytime behaviour, self-mutilation behaviors such as genital cutting, self-burning, and punching through windows were documented in patients with nocturnal DD during sleep.21 Dysphoria is a hallmark of borderline personality disorder, and this is often associated with the initiation of self-mutilating and suicidal behaviors. Comorbidity with borderline features is high in patients with DD, particularly dissociative identity disorder.22 In a recent study we demonstrated a strong association between nightmares and suicidal behavior in major depression.2 This is the first study reporting an association of ND with suicidal behavior in DD patients.

In conclusion, ND is common among patients with DD. Nightmare disorder seems to be associated with self-mutilation, suicidal behavior, and borderline personality. It may be reasonable to attribute a role to nightmares as an adaptive coping strategy in DD. The dreams reduce the intensity of the emotional distress by juxtaposing the current trauma with various other events  in  the  person's  life,  making  connections  to other similar or not-so-similar events. When trauma is dreamt about it is no longer uniquely distressing; it gradually becomes part of a fabric or network. Thus, dreaming has an adaptive function and nightmares are common following a trauma.23 Nightmares or dreams of DD patients can be used to facilitate the therapy of these disorders. Future research is needed to demonstrate the usage of nightmares or dreams in the psychotherapy of these patients.

Ancillary