Download A Comparison of Lifelong and Posttrauma Nightmares

A Comparison of Lifelong and Posttrauma Nightmares
in a Civilian Trauma Sample: Nightmare Characteristics,
Psychopathology, and Treatment Outcome
Joanne L. Davis, Kristi E. Pruiksma, Jamie L. Rhudy, and Patricia Byrd
University of Tulsa
Nightmares and sleep disturbances are thought to play a key role in the development of posttrauma problems. Research efforts have increased in an attempt to
understand this association. The present study examined differences in nightmare
characteristics, related psychopathology, treatment outcome, and trauma history
among trauma-exposed individuals whose nightmares began before a traumatic
event and those whose nightmares began after a traumatic event, while controlling for posttraumatic stress disorder status. Individuals whose nightmares began
following a trauma experienced more depression and posttraumatic stress symptoms and poorer sleep quality, reported a higher number of traumatic events, and
were more likely to report nightmares replicative of or similar to the trauma than
those whose nightmares began before the trauma. No other between-groups
differences were found for nightmare characteristics or response to treatment.
This study is an important step in understanding the nature of nightmares and
their relationship to traumatic events and consequences, but additional research
is warranted.
Keywords: nightmares, trauma, posttraumatic stress disorder, sleep disturbance
Nightmares and sleep disturbances are increasingly viewed as potential key
factors in the development and maintenance of long-term problems after exposure
to a traumatic event. Two types of nightmares are discussed in the literature.
Idiopathic or lifelong nightmares (LLNM) essentially arise from an unknown
etiology, although certain medications, physical conditions, or life stressors may be
associated with these nightmares (e.g., Nielsen & Zadra, 2005). Posttrauma nightmares (PTNM) arise after the experience of a traumatic event. To date, limited
information is available regarding trauma-exposed individuals who experienced
nightmares before the traumatic event (LLNM) and whether, and to what extent,
these individuals differ from those whose nightmares began following a traumatic
event (PTNM) with regards to characteristics of the nightmares, sleep, related
psychopathology, and trauma history. It is unclear from the previous literature
Joanne L. Davis, Kristi E. Pruiksma, Jamie L. Rhudy, and Patricia Byrd, Department of Psychology, University of Tulsa.
Correspondence concerning this article should be addressed to Joanne L. Davis, 800 South Tucker
Drive, 308G Lorton Hall, Department of Psychology, University of Tulsa, Tulsa, OK 74104. E-mail:
[email protected]
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Dreaming
2011, Vol. 21, No. 1, 70 – 80
© 2011 American Psychological Association
1053-0797/11/$12.00 DOI: 10.1037/a0022862
Comparison of Lifelong and Posttrauma Nightmares
71
whether differences found can be attributed to the nightmares themselves, as
studies typically compare individuals with nightmares and trauma and posttraumatic stress disorder (PTSD) with individuals with nightmares but without trauma
and PTSD. This study sought to assess differences in nightmare characteristics,
psychopathology, and treatment response in a sample of trauma-exposed individuals whose nightmares began either before or following a traumatic event.
To date, many studies have evaluated the dreams of people exposed to trauma;
however, few have differentiated between those whose nightmares started before the
trauma and those whose nightmares started after the trauma. Van der Kolk, Blitz, Burr,
Sherry, and Hartmann (1984) compared 15 combat veterans with PTSD and chronic,
frequent nightmares (PTNM) with 10 noncombat veterans without PTSD but with
LLNM. All participants completed a semistructured interview. Results indicated that
PTNMs tended to occur earlier in the night (between 1 a.m. and 3 a.m.), although this
was not a statistically significant difference. Statistically significant differences included
that those with PTNMs had more frequent and repetitive nightmares, were more likely
to have content that replicated an actual event, and were more likely to be accompanied by gross body movement. Limitations of this study included a lack of evaluation
of other types of trauma. Furthermore, it is unclear whether differences were related
specifically to the different types of nightmares or to differences in combat experience
or the presence of PTSD.
Germain and Nielsen (2003b) compared individuals with LLNMs and no
PTSD with trauma-exposed individuals with nightmares and PTSD (PTNMs) and
a healthy control group on subjective psychopathology questionnaires and objective laboratory-recorded sleep parameters. Four of the 11 individuals in the LLNM
group and one control participant reported a trauma, although they did not meet
criteria for current or past PTSD. Nine individuals with PTNMs, 11 individuals with
LLNMs, and 12 individuals with no sleep or dream disturbances (control) underwent in-home polysomnography over 2 consecutive nights. Only data from the
second night were included in analyses. Results indicated that those with PTNMs
reported more distress on all measures than the control group and more depression,
nightmare distress, and posttraumatic symptom severity than the LLNM group.
The LLNM group differed significantly from the control group on nightmare
distress. Polysomnography results indicated that the PTNM group exhibited more
nocturnal awakenings, more wake time after sleep onset, and worse sleep efficiency
than the control group and more nocturnal awakenings and more wake time after sleep
onset than the LLNM group. The two nightmare groups did not differ in periodic limb
movements but exhibited more movements than the control group, and there were no
differences among the three groups on REM sleep and sleep stage measures. As with
the van der Kolk et al. (1984) study, it is unclear whether psychopathology and sleep
problems are more closely associated with the trauma, PTSD, or the nightmares.
Thus, there is some evidence of differences in characteristics and related
psychopathology for LLNMs and PTNMs, although nightmares have been confounded with trauma exposure and PTSD in previous studies. If such differences do
exist, controlling for PTSD and trauma exposure, another important line of inquiry
is to determine whether different treatment approaches may be warranted. Research suggests that cognitive– behavioral approaches are effective in diminishing
the frequency and intensity of nightmares, as well as related sleep problems and
psychopathology (Davis & Wright, 2007; Krakow et al., 2001). Few studies have
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Davis, Pruiksma, Rhudy, and Byrd
examined this efficacy by type of nightmare, however. Van der Kolk and colleagues
(1984) found a trend ( p ⫽ .056) in that 67% of individuals with PTNMs reported
their nightmares responded to various medications compared with 22% of LLNMs.
Germain and Nielsen (2003a) examined the effect of a single session of imagery
rehearsal therapy on the frequency of nightmares and bad dreams, psychological
distress, and objectively measured sleep quality among six individuals with PTNM
and PTSD and six LLNM sufferers without PTSD. Treatment led to statistically
significant reductions in anxiety and PTSD severity for the PTNM group and in
depression for the LLNM group. Effect sizes were large in a number of nonsignificant comparisons, such as retrospective estimation of nightmare frequency, prospective estimations of bad dreams and sleep terrors, anxiety, depression, and
nightmare distress. It remains unclear, however, whether differences observed in
these studies were due to trauma exposure, PTSD, or the type of nightmares.
The purpose of the present study was to examine differences between traumaexposed individuals whose nightmares began before a traumatic event (LLNM) and
those whose nightmares began after a traumatic event (PTNM) while controlling
for PTSD status. Data for this study were drawn from a larger study (Rhudy et al.,
2010) of a cognitive– behavioral treatment for nightmares: exposure, relaxation, and
rescripting therapy (ERRT; Davis, 2009; Davis & Wright, 2006, 2007). We examined
possible differences in three areas: nightmare characteristics (e.g., frequency, severity,
number of different nightmares, panic symptoms on wakening, similarity to trauma),
psychopathology (e.g., PTSD symptoms, depression, sleep problems), and treatment
response. We also explored the trauma histories of each group.
We hypothesized that individuals with PTNMs would exhibit the following characteristics of nightmares compared with those with LLNMs: more frequent and severe
nightmares, greater number of different nightmares experienced, shorter duration of
nightmare suffering (controlling for participant age), and greater number of panic
symptoms on waking from a nightmare. In terms of content, we hypothesized that
those with PTNMs would be more likely to report nightmares that are replicative or
similar to the traumatic event compared with those with LLNMs.
We also hypothesized that individuals with PTNMs would report greater
related psychopathology, including more depression, more frequent and severe
PTSD symptoms, poorer sleep quality, greater fear of going to sleep, and feeling
more depressed and less rested on waking.
We hypothesized that the LLNM and PTNM groups would differ in treatment
response, although the nature of these differences was not specified.
Finally, we compared the trauma histories of individuals in the LLNM and
PTNM groups. Specifically, we investigated overall number of traumas, and
whether the LLNM group reported more traumatic events before the age of 18 than
did the trauma-related nightmare group.
METHOD
Procedure
All procedures were approved by the university Institutional Review Board.
Participants were included in the treatment study if they were at least 18 years old,
Comparison of Lifelong and Posttrauma Nightmares
73
had experienced a traumatic event (as defined in Diagnostic and Statistical Manual
of Mental Disorders [4th ed., text rev.]; DSM–IV–TR; American Psychiatric Association, 2000), and had experienced at least one nightmare per week for the past 3
months. Participants were excluded if they exhibited apparent psychosis, mental
retardation, substance dependence, suicidal ideation, or recent parasuicidal behavior. Participants were recruited through radio ads, fliers, and referrals from therapists in the community. Individuals interested in the study completed a brief phone
screen for inclusion and exclusion criteria and were invited to complete a more
thorough initial assessment. Participants were randomized to a treatment or waitlist
control group, and were assessed at 1 week, 3 months, and 6 months posttreatment.
Data from the initial and 6-month assessments were used for the purposes of this
study. Participants who indicated that their nightmares began after a trauma were
included in the PTNM group, whereas participants who indicated their nightmares
began before exposure to trauma were included in the LLNM group.
Participants
Four participants indicated that they were unsure when their nightmares began
and were excluded from analyses. A total of 54 participants were included in the
study, with 75.9% (n ⫽ 41) reporting PTNMs and 24.1% (n ⫽ 13) reporting
LLNMs. With regard to demographic information, participants were 77.8% women
(n ⫽ 42), 81.5% Caucasian (n ⫽ 44), 51.9% married or living with a significant other
(n ⫽ 28), 70.4% employed or students, with a mean age of 38.28 years (SD ⫽ 12.16)
and a mean of 14.37 (SD ⫽ 2.45) years of schooling. Participants reported a mean
of 5.55 (SD ⫽ 2.66, range ⫽ 2–10) traumas, with the most frequent types of trauma
reported being unwanted sexual contact (59.3%), being attacked with a weapon
(59.3%), and car accident (57.4%).
Measures
A self-report demographic questionnaire was used to obtain information about
age, relationship status, years of education, ethnicity, and vocational status.
The Trauma Assessment for Adults: Self-Report Version (TAA; Resnick,
Best, Kilpatrick, Freedy, & Falsetti, 1993) assesses lifetime history of potentially
traumatic events. The TAA consists of 13 items and includes follow-up questions to
assess perceived threat. For the present study, the TAA was modified to include an
additional five items to assess for hate crimes. Ages at first and most recent
occurrence were determined for multiple incidents of a given type.
The Clinician-Administered PTSD Scale (Blake et al., 1990) is a semistructured clinical interview and was used to determine current and lifetime PTSD
diagnoses. It consists of 17 items assessing frequency and severity of PTSD symptoms (0 ⫽ none/never to 4 ⫽ daily or almost daily/extreme). The “F1/I2” rule
(frequency coded at least 1 and intensity coded at least 2 for the past month) was
used to determine symptom presence and diagnosis.
The Modified PTSD Symptom Scale—Self-Report (Resick, Falsetti, Resnick,
& Kilpatrick, 1991) is a modification of the PTSD Symptom Scale (Foa, Riggs,
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Davis, Pruiksma, Rhudy, and Byrd
Dancu, & Rothbaum, 1993) developed to assess both frequency and severity of 17
PTSD symptoms corresponding to criteria in DSM–IV–TR. Each symptom is rated
for frequency on a 4-point Likert scale (0 ⫽ not at all to 3 ⫽ 5 or more times per
week/very much/almost always) and a 5-point Likert scale for severity (0 ⫽ not at all
distressing to 4 ⫽ extremely distressing). The internal consistency of the full scale
has been reported at levels of .96 and .97 in treatment and community samples,
respectively (Falsetti, Resick, Resnick, & Kilpatrick, 1992, as cited in Falsetti,
Resnick, Resick, & Kilpatrick, 1993). The total score for symptom frequency and
severity was used in the current study.
The Beck Depression Inventory—Second Edition (BDI–II; Beck, Steer, &
Brown, 1996) is a 21-item self-report measure of depressive symptomatology. Each
item has four optional responses ranging from not present to severe. The BDI–II
yields scores ranging from 0 to 63, with higher scores reflecting greater symptomatology.
The Pittsburgh Sleep Quality Index (PSQI; Buysse, Reynolds, Monk, Berman, & Kupfer, 1989) is a self-report measure designed to assess certain
qualities and problems associated with sleep. Participants rate quality of sleep
and degree of sleep difficulties for a set period preceding the assessment. A
global sleep quality score is obtained by summing the seven component scores,
and higher scores reflect poorer sleep quality. The global score may range
from 0 to 21. Buysse and colleagues (1989) identified a cutoff score of 5 to
distinguish “good” sleepers from “poor” sleepers, with a diagnostic sensitivity
of 89.6% and specificity of 86.5%. The present study examined the global sleep
quality index.
The Trauma-Related Nightmare Survey (Davis, Wright, & Borntrager, 2001)
was used to assess characteristics of chronic nightmares. Likert-type, categorical,
and open-ended questions assess the frequency, severity, and duration of nightmares, as well as cognitions, emotions, and behaviors related to nightmares. Davis
and Wright (2007) reported convergent validity with daily behavioral records of
sleep and nightmares: nights with nightmares (r ⫽ .82) and number of nightmares
(r ⫽ .81) and the Modified PTSD Symptom Scale—Self-Report nightmare frequency (r ⫽ .64) and severity (r ⫽ .45).
Treatment
ERRT is a cognitive– behavioral treatment for trauma-related nightmares and
is described in detail elsewhere (Davis, 2009; Davis & Wright, 2006). ERRT is
conducted for 2 hours once a week for 3 consecutive weeks and may be used in
either an individual or group format. Treatment consists of psychoeducation about
trauma, PTSD, and nightmares, relaxation training, modification of sleep habits,
exposure to the nightmare, and rescription of the nightmare based on traumarelated themes. Previous findings demonstrated decreased nightmare frequency,
depression, and PTSD symptoms, improvement in sleep quality (Davis & Wright,
2007) as well as physiological indices of nightmare-related fear (Rhudy et al., 2010)
following ERRT.
Comparison of Lifelong and Posttrauma Nightmares
75
Data Analysis
Chi-square analyses (with Yates continuity correction) were conducted to
examine differences between LLNMs and PTNMs on demographic variables,
similarity between the nightmare and the traumatic event, current PTSD diagnosis, and childhood trauma (trauma before 18 years of age). Fisher’s exact test
of significance was used for chi-square analyses not meeting assumptions because of cell frequency less than 5. General linear model one-way analyses of
covariance were conducted to examine the association of type of nightmare with
nightmare characteristics, related psychopathology, and treatment response
using change scores, while controlling for PTSD diagnosis. Two-tailed tests were
used for all analyses.
RESULTS
Preliminary Analyses
As shown in Table 1, analyses indicated that there were no differences between
participants with LLNMs and PTNMs on demographic variables. Chi-square analyses for gender, race, and vocation did not meet chi-square assumptions because of
low cell frequency in the LLNM group, so Fisher’s exact test of significance was
used. PTSD diagnosis did not differ between the PTNM (n ⫽ 24, 58.5%) and the
LLNM (n ⫽ 5, 38.5%) groups, ␹2(1, N ⫽ 54) ⫽ 1.60, ns.
Table 1. Demographics of Study Participants
Demographic
Gender, n (%)
Male
Female
Race, n (%)
Caucasian
Not Caucasian
Relationship status, n (%)
Married/cohabitating
Single/divorced/widowed
Employment status, n (%)
Employed/student
Unemployed/retired
Mean (SD) age (years)
Mean (SD) education (years)
Pretrauma
nightmares
(n ⫽ 13)
Posttrauma
nightmares
(n ⫽ 41)
3 (23.1)
10 (76.9)
9 (22.0)
32 (78.0)
12 (92.3)
1 (7.7)
32 (78.00
9 (22.0)
8 (61.5)
5 (38.5)
20 (48.8)
21 (51.2)
10 (76.9)
3 (23.1)
28 (68.3)
13 (31.7)
39.85 (13.47)
15.31 (2.59)
37.78 (11.85)
14.07 (2.36)
␹2 (1)
␾
0.00
.01
0.55
.16
0.23
–.11
0.06
.08
F (2, 55)
␩p2
0.28
2.58
.01
.05
Note. Effect sizes for analyses of variance were calculated using partial eta-squared (␩p2). According to
Cohen (1988), .01 ⫽ small effect, .06 ⫽ medium effect, and .14 ⫽ large effect. Effect sizes for chi-square
were calculated using phi coefficient (␾). According to Cohen (1988), .10 ⫽ small effect, .30 ⫽ medium
effect, and .50 ⫽ large effect.
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Davis, Pruiksma, Rhudy, and Byrd
Nightmare Characteristics
See Table 2 for statistical data for all hypotheses. Controlling for PTSD status,
hypotheses regarding nightmare characteristics mostly were not supported as only
one difference was found between nightmare groups. The percentages of individuals with LLNMs reporting similarity of their nightmare content to a traumatic
Table 2. Differences Among Lifelong Nightmare Sufferers and Posttrauma Nightmare Sufferers
Lifelong
Nightmares
Variable
Nightmare characteristics
Number of nightmares (past week)
Nights with nightmares (past week)
Nights with multiple nightmares
(past week)
Severity of nightmares (range: 0–4)
Panic symptoms on waking
(range: 0–13)
How long having nightmares
(months)
Related psychopathology
Depression (BDI–II; range: 0–63)
PTSD symptoms (MPSS; range:
0–119)
Sleep quality (PSQI; range: 0–21)
Feeling depressed on waking
(range: 0–4)
Fear of sleep (range: 0–4)
Restfulness on waking (range: 0–4)
Treatment response
Change in nightmares per week
Change in nights with nightmares per
week
Change in nightmare severity
Change in total PTSD symptoms past
week (CAPS)
Change in total PTSD symptoms past
month (CAPS)
Change in total depression
Change in total sleep quality
Trauma exposure
Number of traumas
Posttrauma
nightmares
F (2, 55)
␩p2
1.71
1.78
1.88
2.03
.04
.04
1.73
3.12
1.76
0.75
3.71
0.39
.07
.01
39
5.59
3.22
1.02
.02
164.21
36
174.46
139.29
0.36
.008
14.92
11.52
41
23.00
10.80
4.35ⴱ
.08
12
13
26.50
10.27
27.96
4.81
40
38
57.58
13.84
20.02
4.07
15.27ⴱⴱ
4.30ⴱ
.24
.08
13
13
13
0.85
1.38
1.23
1.21
1.44
1.01
40
41
40
2.00
1.51
1.05
1.13
1.12
0.85
7.98ⴱ
0.03
0.13
.14
.00
.00
6
2.25
2.32
13
1.73
4.12
0.03
.00
6
6
1.67
1.67
1.03
1.21
15
14
2.60
1.86
3.40
1.29
1.63
0.38
.08
.03
6
27.67
31.15
13
43.08
20.59
1.87
.10
6
6
6
28.00
0.58
–0.33
32.92
3.38
2.16
12
15
13
45.17
⫺2.73
⫺1.23
24.91
14.07
4.38
1.66
0.30
0.16
.10
.02
.01
12
3.83
2.72
35
6.14
2.38
3.31ⴱ
.12
n
Mean
13
12
3.73
2.29
13
13
n
Mean
3.70
1.10
41
41
2.91
3.18
0.65
2.92
1.07
0.64
37
41
13
4.46
1.98
12
230.50
13
Nightmare content: Replicative/similar to trauma
Trauma before age 18
SD
SD
n
%
n
%
␹ (1)
␾
3
9
33.3
69.2
28
32
71.8
78.0
4.73ⴱ
.08
.10
.09
2
Note. All Fs reported except for number of traumas are after controlling for posttraumatic stress
disorder (PTSD) diagnosis. All variables assessed with the Trauma-Related Nightmare Scale except
where specified. BDI–II ⫽ Beck Depression Inventory; PSQI ⫽ Pittsburgh Sleep Quality Index;
MPSS ⫽ Modified PTSD Symptom Scale; CAPS ⫽ Clinician-Administered PTSD Scale. Effect sizes for
analyses of covariances were calculated using partial eta-squared (␩p2). According to Cohen (1988), .01 ⫽
small effect, .06 ⫽ medium effect, and .14 ⫽ large effect. Effect sizes for chi-square were calculated using
phi coefficient (␾). According to Cohen (1988), .10 ⫽ small effect, .30 ⫽ medium effect, and .50 ⫽ large
effect.
ⴱ
p ⬍ .05. ⴱⴱ p ⬍ .001.
Comparison of Lifelong and Posttrauma Nightmares
77
event were 0% exactly like the trauma, 33% similar to the trauma, and 67%
unrelated to the trauma. For PTNM individuals, the percentages were 33% exactly
like the trauma, 39% similar to the trauma, and 28% unrelated to the trauma. For
the analyses, individuals with replicative, similar, and dissimilar nightmares were
collapsed into two groups: replicative (replicative and similar) and not replicative
(dissimilar) because of low cell frequencies. Fisher’s two-tailed test was significant
and indicated that the PTNM group was more likely to report replicative or similar
nightmares than the LLNM group.
Related Psychopathology
Hypotheses regarding related psychopathology were partially supported. The
PTNM group reported greater depression on waking, greater global depression,
greater PTSD symptom severity, and poorer sleep quality. The groups did not
differ, however, on fear of sleep or feeling rested on waking. PTSD diagnosis
contributed to global sleep quality, F(1, 48) ⫽ 10.98, p ⬍ .01, ␩p2 ⫽ .19, and PTSD
symptom severity, F(1, 49) ⫽ 4.98, p ⬍ .05, ␩p2 ⫽ .09.
Treatment Response
Contrary to the hypothesis, the LLNM and PTNM groups exhibited similar
patterns of response to treatment. Regardless of whether PTSD status was controlled, there were no differences between the PTNM group and the LLNM group
in terms of baseline to 6-month assessment change in nightmares per week, nights
with nightmares per week, nightmare severity, change in total past-week and
past-month PTSD symptoms, depression, or sleep quality.
Trauma Exposure
Chi-square assumptions for cell frequency were not met, so Fisher’s exact test
of significance was used. The LLNM and PTNM groups did not differ with respect
to the number of individuals who experienced a trauma before the age of 18.
However, PTNM sufferers reported significantly more traumas.
DISCUSSION
The present study examined differences between trauma-exposed persons with
LLNMs and trauma-exposed persons with PTNMs. Few studies have investigated
such differences to date, and none have controlled for the influence of PTSD.
Consistent with previous research comparing nightmares between individuals with
and without trauma exposure or PTSD, the present study found that the PTNM
group reported greater psychopathology. Moderate effect sizes were found for
global depression and sleep quality, and large effect sizes were found for PTSD
symptom severity and depression on waking, while controlling for PTSD diagnosis.
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Davis, Pruiksma, Rhudy, and Byrd
It is possible that those who experienced nightmares prior to trauma may have
found ways to cope with the sleep disturbances and the lower quality and quantity
of sleep; thus, they were less vulnerable to related pathology after experiencing a
trauma. This finding is inconsistent, however, with results reported by Mellman,
David, Kulick-Bell, Hebding, and Nolan (1995), who found that individuals with
sleep disturbances before the traumatic event were more vulnerable to posttrauma
problems. Future research is needed to determine whether pretrauma nightmares
and sleep problems provide a degree of protection or vulnerability to posttrauma
difficulties.
PTSD diagnosis was controlled in each analysis and was found to be significantly associated only with initial global sleep quality and PTSD symptom severity.
Given the cross-sectional nature of the present study, it is unclear how sleep quality
and PTSD may be associated. Nightmares and poor sleep quality may increase
one’s risk for developing PTSD. Indeed, Wang, Wilson, and Mason (1996) suggested that sleep problems often precede other difficulties and may exacerbate
symptomatology. Furthermore, prospective studies have found that acute posttrauma nightmares and sleep problems are associated with difficulties, including
PTSD, over time (e.g., Koren, Arnon, Lavie, & Klein, 2002). Another possibility is
that aspects of PTSD, sleep problems, and nightmares may develop and be maintained in concert with the rest of the PTSD symptoms. More prospective studies are
needed to determine when particular symptoms develop posttrauma and how they
relate to the development or maintenance of other indices of distress.
In terms of nightmare characteristics, the only difference found between
LLNMs and PTNMs was that the PTNM group was more likely to report nightmares similar to or replicative of the trauma. Indeed, whereas no one in the LLNM
group reported experiencing replicative nightmares, one third of the PTNM group
did. It is interesting that one third of those with LLNMs reported that their
nightmares were similar to the traumatic event. This finding provides some evidence that nightmares may change in content following a trauma, as discussed by
Hartmann (1998). Longitudinal studies would be helpful in further elucidating the
nature and course of nightmares.
We examined the response of individuals to a treatment for chronic nightmares
in trauma-exposed persons. Results indicated that despite differences in associated
psychopathology, the treatment was successful in treating both types of nightmares
in terms of changes in nightmare frequency, severity, PTSD symptoms, depression,
and sleep quality. PTSD diagnosis was not associated with change in any variable.
This suggests that cognitive– behavioral therapy for nightmares is effective regardless of the type of nightmare or degree of psychopathology and can have generalized effects beyond nightmare symptoms to other areas of psychopathology (e.g.,
PTSD, depression).
We examined whether there were important differences in the trauma histories
between individuals with LLNMs and individuals with PTNMs. Those with PTNMs
reported experiencing a greater number of traumas, but the groups did not differ in
terms of the length of time they had experienced nightmares or in experiencing
trauma before the age of 18. However, future research should further examine this
question using differing age ranges, traumas experienced, and the nature and extent
of the trauma.
Comparison of Lifelong and Posttrauma Nightmares
79
Limitations
Several limitations exist in the present study. Small sample sizes of those
reporting LLNMs limited the power to detect differences that may have existed. In
addition, trauma was examined as one general variable. Future research should
examine whether differences in characteristics of nightmares exist between interpersonal, environmental, or combat-related traumatic experiences. Finally, the
present study was part of a larger study evaluating the impact of a treatment
designed for chronic nightmares in trauma-exposed persons. As such, participants
were required to experience at least one nightmare per week for at least 3 months.
Our participants reported a mean duration for nightmares of 16 years. Furthermore, all participants were seeking treatment specifically for nightmares. As such,
this was a sample experiencing severe difficulties with nightmares. This degree of
severity may be not be representative of trauma-exposed individuals at large;
however, that remains to be determined.
Conclusions
Overall, these findings suggest that, although most nightmare characteristics
and treatment response do not differ between individuals with LLNMs or PTNMs,
individuals who experience LLNMs experience fewer disturbances than individuals
with PTNMs. Additional research is warranted to determine whether these findings
generalize to other samples and to determine whether experiencing nightmares
prior to a trauma may provide some protection against long-term problems.
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