Reference:
Carleton, R. N., Mulvogue, M. K., Thibodeau, M. A., McCabe, R. E., Antony,
M. M., & Asmundson, G. J. G. (2012). Increasingly
certain about uncertainty: Intolerance of uncertainty across anxiety and
depression. Journal of Anxiety
Disorders, 26, 468-479. doi:10.1016/j.janxdis.2012.01.011
Aims of the Current Study
·
This
study is the first systematic attempt to examine intolerance of uncertainty (IU)
endorsement rates and response patters across undergraduate, community, and
clinical samples. IU is a potentially important transdiagnostic construct involved
in the development and maintenance of anxiety and mood disorders.
Introduction and Literature Review
·
Identifying
and understanding constructs common to anxiety and depression, such as IU, may
provide directions for investigating transdiagnostic vulnerabilities and for developing
transdiagnostic treatment protocols.
·
IU
is defined as a negative response to ambiguity/uncertainty, beliefs about
uncertainty as threatening, and the inability to cope with ambiguity and change
·
Two
dimensions of IU
o
Prospective
IU = the cognitively focused dimension of IU (e.g., “Unforeseen events upset me
greatly”) à expected to be
more related to worry and obsessive compulsive symptoms
o
Inhibitory
IU = the behaviorally focused dimension of IU (e.g., “The smallest doubt can
stop me from acting”) àexpected to be
more related to social anxiety, panic, agoraphobia, and depression.
·
Growing
evidence that IU may be a transdiagnostic cognitive construct across
undergraduate, community, and clinical populations
o
Especially
GAD, but also OCD, social anxiety disorder (SAD), panic disorder with or
without agoraphobia (PDA), and major depressive disorder (MDD)
Hypotheses
·
Endorsement
rates:
o
IU
endorsement is expected to be higher in clinical sample relative to both the
undergraduate and community samples
o
Within
the clinical sample: OCD and GAD > MDD, PDA, and SAD
·
2-factor
solution of the IUS-12 was expected
·
Prospective
IU was hypothesized to be more related to worry and OCD symptoms
·
Inhibitory
IU was hypothesized to be more related to SAD, PDA, and MDD
Method
·
Participants
o
376
outpatients: SAD (n = 120, 32%), PDA
(n = 89, 24%), GAD (n = 63, 17%), OCD (n = 60, 16%), and MDD (n =
26, 7%)
o
428
undergraduates
o
571
community members
·
Measures
o
Intolerance
of Uncertainty Scale, short form (IUS-12)
o
Structured
Clinical Interview for DSM-IV (SCID)
·
Analyses
o
Empirical
distributions of the IUS-12 scores across diagnostic, community, and
undergraduate groups were studied using Kernel density estimation curves
o
Two
ANOVAs comparing total and subscale means of the IUS-12 across groups
§ ANOVA 1: primary
GAD vs. primary OAD + co-occurring GAD vs. primary OAD (w/o GAD) vs. primary
MDD vs. undergraduates vs. community (Tukey post-hoc comparisons, α = .01)
§ ANOVA 2: SAD vs.
PDA vs. GAD vs. OCD vs. MDD vs. undergraduates vs. community (Tukey post-hoc
comparisons)
o
Confirmatory
factor analysis (CFA) for 3 purposes:
§ (1) Assess the
fit of the presumed 2-factor structure for each of the clinical, undergraduate,
and community samples
§ (2) Assess if
the IUS-12 factor structure, measurement weights, and structural covariances
differed for men vs. women
§ Assess if the
IUS-12 factor structure, measurement weights, and structural covariances
differed for diagnostic groups
Results
·
Some
demographic differences between groups (e.g., age, gender)
·
Items
and summed scale alternatives demonstrated acceptable skew and kurtosis
·
Almost
no statistically significant differences between men and women on the total or
subscale scores of the IUS-12 in any sample
·
Kernel
distribution estimations: 3 general patterns
o
SAD,
GAD, OCD, and MDD demonstrated very similar distributions: high range of IUS-12
scores, normal to negatively skewed
o
Undergraduate
and community samples demonstrated very similar distributions to each other:
lower range of IUS-12 scores, disparate from the clinical groups, positively
skewed
o
PDA
wider range of IUS-12 scores
·
ANOVA
1
o
Primary
GAD, primary OAD + co-occurring GAD, primary OAD (w/o GAD), primary MDD >
undergraduates, community
·
ANOVA
2
o
SAD,
PDA, GAD, OCD, MDD > undergraduates, community
o
Re-ran
ANOVA excluding participants with a comorbid diagnosis à still no statistically
significant differences between clinical groups
·
CFA
o
2-factor
structure was statistically superior to a unitary structure for men and women
in all 3 samples
·
Invariance
analyses
o
No
differences between men and women based on measurement weights or structural
covariances for any of the 3 samples (clinical, undergraduate, community),
suggesting response patterns for men and women were comparable
o
No
differences between undergraduate and community samples based on measurement
weights suggesting response patterns were largely similar; however, the
structural covariances were significant different
o
Significant
and substantial differences in response patterns based on measurement weights
or structural covariances between the clinical sample and each of the
undergraduate and community samples
o
No
differences across the diagnostic groups based on measurement weights or
structural covarainces
Discussion
·
Three
important contributions
o
First
direct comparative analyses of IU response patterns and empirical
distributions, as measured by IUS-12, across clinical, undergraduate, and
community samples
§ Empirical
distributions of IU for those with principal SAD, GAD, OCD, and MDD very
similar (although PDA had relatively large variance of scores)
§ No statistically
significant differences between any diagnostic groups
§ IU appears to
not be specific to any given disorder (e.g., OCD or GAD) but instead seems to
represent a broad transdiagnostic cognitive vulnerability
o
First
presentation of normative IUS-12 data for several clinical samples and further
assessment of the proposed IUS-12 factor structure
§ 2-factor
structure was supported and superior to unitary alternative for all three
samples
o
Further
psychometric support for the IUS-12 as being invariant across sex with a robust
factor structure
§ Response
patterns of undergraduate and community participants were largely comparable;
clinical response patterns were also comparable to one another but were
substantially different from undergraduate/community samples
·
Limitations
o
Samples
sizes for each diagnostic group within the clinical sample are insufficient for
robust CFA (preliminary analyses)
o
No
inter-rater reliability information for SCID diagnoses
o
Clinical
sample had high levels of comorbidity (not diagnostically “pure”)
o
Undergraduate
and community samples were not diagnostically assessed
o
The
causality of IU and the development of anxiety/depressive disorders cannot be
determined
o
Unable
to determine mechanisms or manner in which IU relates to each disorder
o
Sample
primarily Caucasian
·
Future
directions
o
Do
individuals with anxiety and depression experience greater IU in general or IU specific
only to their disorder (e.g., to bodily sensations in panic)
o
Incorporating
IU-specific treatment components into therapy (e.g., in vivo exposure to
uncertainty)
o
Further
taxometric investigation of IU as measured by the IUS-12
o
Further
studies directly comparing IUS-27 and IUS-12
Discussion Questions
·
Based
on the results reported in this study (and reviewed from previous studies),
does it seem to you that IU is indeed a transdiagnostic construct across
anxiety and depression (vs. unique to OCD and/or GAD)?
o
If
so what evidence do you find most compelling?
o
If
not, what other information would you need in order to make your decision?
·
What
is the next study in this area that you think needs to be done?
·
Based
on your research knowledge and clinical experiences, what are your preliminary
thoughts/hypotheses about the empirical question raised in the future
directions section about whether individuals with anxiety and depression
experience greater IU in general or IU specific only to their disorder (e.g.,
to bodily sensations in panic)?
·
Do
any of the limitations mentioned above (e.g., small sample sizes, no diagnostic
inter-rater reliability) particularly concern you?
·
For
those of you who research disorders/problems outside of anxiety and depression,
are there ways that you can see this work on IU extending to other
concerns/populations?
Sorry for the delay in response, thanks so much for sending your review of this article, I think this is a really interesting area and construct. A few thoughts on some of the specific questions you raised:
ReplyDelete· Based on the results reported in this study (and reviewed from previous studies), does it seem to you that IU is indeed a transdiagnostic construct across anxiety and depression (vs. unique to OCD and/or GAD)?
o If so what evidence do you find most compelling?
o If not, what other information would you need in order to make your decision?
I do think that IU appears to be more of a transdiagnostic construct rather than specific to any diagnosis. For me, the elevated scores across all diagnostic groups relative to community/student groups, and the similarity in distribution for all diagnostic groups was compelling evidence to suggest IU does not only show up in certain sets of patients. That the IU construct may also be multifactorial, and the factors relate differentially to diagnostic groups further supports its applicability to a range of diagnoses, allowing for some specificity of relations within the broader construct. Other information I’d be interested in would be results from treatment outcome studies: does targeting IU in each of these disorders lead to similar symptom change? In addition, studies investigating how IU functions within each diagnostic group would be useful – for instance does IU function as an etiology, or a symptom of, disorders? And is it the same across all groups or function differently in different diagnoses?
I also wonder what consequences some of the changes in DSM-5 would have on this model. For instance, OCD is moving to the Obsessive Compulsive and Related Disorders category and PTSD is moving to the Trauma category. If these are no longer classified as Anxiety disorders, but have a core component of IU, the theory that IU links mood and anxiety disorders is incomplete. Future studies could examine the role of IU in other disorders in these new categories, potentially supporting even greater transdiagnostic applicability of IU.
What other constructs do you think might fit this transdiagnostic model?
I definitely agree that a great next step in this area would be investigating IU as it relates to treatment outcome studies. Specifically I'd be interested in whether incorporating individualized information about IU dimensional vulnerabilities into IU-specific treatments is beneficial for treatment outcomes (and whether IU is a mechanism of treatment change in these treatments). I am most familiar with the research on IU as it pertains to OCD, and some IU-specific
ReplyDeletetreatments that come to mind that could be examined include in vivo or imaginal exposure to IU (Jon Grayson has written a lot in this area) and cognitive restructuring about the need to be certain (Sabine Wilhelm and Gail Steketee published a 2006 manual about cognitive therapy for OCD with an entire chapter devoted to "Desire for Certainty").
I also agree with your points about DSM-5. Although for me this research on IU as a transdiagnostic construct simply provides more questions as to why OCRDs and trauma-related disorders are being separated from the anxiety disorders category in the first place (but that is probably an entire other journal club discussion!).
Another transdiagnostic construct I have been coming across a lot is psychological flexibility (also sometimes written about as "distress tolerance"), which seems central to a lot of psychological concerns. But I would love to hear if there are others that people have noted!