Disgust Theory Through the Lens of Psychiatric Medicine

Abstract

The elicitors of disgust are heterogeneous, which makes attributing one function to disgust challenging. Theorists have proposed that disgust solves multiple adaptive problems and comprises multiple functional domains. However, theories conflict with regard to what the domains are and how they should be delineated. In this article, we examine clinical evidence of aberrant disgust symptoms in the contamination subtype of obsessive-compulsive disorder, blood-injury-injection phobia, and posttraumatic stress disorder to adjudicate between two prevailing theories of disgust. We argue that the pattern of disgust sensitivities in these psychiatric disorders sheds new light on the domain structure of disgust. Specifically, the supported domain structure of disgust is likely similar to an adaptationist model of disgust, with more subdivisions of the domain of pathogen disgust. We discuss the implications of this approach for the prevention and treatment of psychiatric disorders relevant to disgust.

Keywords

disgust emotion evolutionary psychology psychiatry psychopathology

Get full access to this article

View all access options for this article.

References

American Psychiatric Association. (1968). Diagnostic and statistical manual of mental disorders (2nd ed.). Washington, DC: Author.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.

Arocho

J. M.

(2015). Moral disgust as a transdiagnostic feature in obsessive-compulsive disorder and posttraumatic stress disorder. Retrieved from ETD Collection for Fordham University database. (AAI3728444)

Athey

A. J.

Elias

J. A.

Crosby

J. M.

Jenike

M. A.

Pope

H. G.

Hudson

J. I.

Brennan

B. P.

(2015). Reduced disgust propensity is associated with improvement in contamination/washing symptoms in obsessive compulsive disorder. Journal of Obsessive Compulsive Related Disorders, 4, 20–24.

Badour

C. L.

Feldner

M. T.

(2016). Disgust and imaginal exposure to memories of sexual trauma: Implications for the treatment of posttraumatic stress. Psychological Trauma: Theory, Research, Practice and Policy, 8, 267–275. doi:10.1037/tra0000079.Disgust

Badour

C. L.

Feldner

M. T.

Blumenthal

Bujarski

S. J.

(2013). Examination of increased mental contamination as a potential mechanism in the association between disgust sensitivity and sexual assault-related posttraumatic stress. Cognitive Therapy and Research, 37, 697–703. doi:10.1007/s10608-013-9529-0

Berle

Starcevic

Brakoulias

Sammut

Milicevic

Hannan

Moses

(2012). Disgust propensity in obsessive-compulsive disorder: Cross-sectional and prospective relationships. Journal of Behavior Therapy and Experimental Psychiatry, 43, 656–663. doi:10.1016/j.jbtep.2011.09.002

Bianchi

K. N.

Carter

M. M.

(2012). An experimental analysis of disgust sensitivity and fear of contagion in spider and blood injection injury phobia. Journal of Anxiety Disorders, 26, 753–761. doi:10.1016/j.janxdis.2012.06.004

Bomyea

Amir

(2012). Disgust propensity as a predictor of intrusive cognitions following a distressing film. Cognitive Therapy and Research, 36, 190–198. doi:10.1007/s10608-010-9331-1

10.

Bomyea

Risbrough

Lang

A. J.

(2012). A consideration of select pre-trauma factors as key vulnerabilities in PTSD. Clinical Psychology Review, 32, 630–641. doi:10.1016/j.cpr.2012.06.008

11.

Brake

C. A.

Rojas

S. M.

Badour

C. L.

Dutton

C. E.

Feldner

M. T.

(2017). Self-disgust as a potential mechanism underlying the association between PTSD and suicide risk. Journal of Anxiety Disorders, 47, 1–9. doi:10.1016/j.janxdis.2017.01.003

12.

Capestany

B. H.

Harris

L. T.

(2014). Disgust and biological descriptions bias logical reasoning during legal decision-making. Social Neuroscience, 9, 265–277. doi:10.1080/17470919.2014.892531

13.

Chapman

H. A.

Anderson

A. K.

(2014). Trait physical disgust is related to moral judgments outside of the purity domain. Emotion, 14, 341–348. doi:10.1037/a0035120

14.

Cisler

J. M.

Olatunji

B. O.

(2010). Components of attentional bias in contamination fear: evidence for difficulty in disengagement. Behaviour Research and Therapy, 48, 74–78.

15.

Connolly

Hallam

R. S.

Marks

I. M.

(1976). Selective association of fainting with blood-injury-illness fear. Behavior Therapy, 7, 8–13. doi:10.1016/S0005-7894(76)80214-6

16.

Coyle

Karatzias

Summers

Power

(2014). Emotions and emotion regulation in survivors of childhood sexual abuse: The importance of “disgust” in traumatic stress and psychopathology. European Journal of Psychotraumatology, 5, Article 23306. doi:10.3402/ejpt.v5.23306

17.

Curtis

(2011). Why disgust matters. Philosophical Transactions of the Royal Society B: Biological Sciences, 366, 3478–3490. doi:10.1098/rstb.2011.0165

18.

Curtis

de Barra

(2018). The structure and function of pathogen disgust. Philosophical Transactions of the Royal Society B: Biological Sciences, 373(1751). doi:10.1098/rstb.2017.0208

19.

Curtis

de Barra

Aunger

(2011). Disgust as an adaptive system for disease avoidance behaviour. Philosophical Transactions of the Royal Society B: Biological Sciences, 366, 389–401. doi:10.1098/rstb.2010.0117

20.

de Jong

P. J.

Merckelbach

. (1998). Blood-injection-injury phobia and fear of spiders: Domain specific individual differences in disgust sensitivity. Personality and Individual Differences, 24, 153–158. doi:10.1016/S0191-8869(97)00178-5

21.

Dewey

Schuldberg

Madathil

(2014). Do peritraumatic emotions differentially predict PTSD symptom clusters? Initial evidence for emotion specificity. Psychological Reports, 115, 1–12. doi:10.2466/16.02.PR0.115c11z7

22.

Ekman

(1992). An argument for basic emotions. Cognition & Emotion, 6, 169–200. doi:10.1080/02699939208411068

23.

Ekman

Friesen

W. V.

(1975). Unmasking the face: A guide to recognizing emotions from facial clues. Los Altos, CA: Malor Books.

24.

Ekman

Friesen

W. V.

O’Sullivan

Chan

Diacoyanni-Tarlatzis

Heider

. . . Tzavaras

(1987). Universals and cultural differences in the judgments of facial expressions of emotion. Journal of Personality and Social Psychology, 53, 712–717. doi:10.1037/0022-3514.53.4.712

25.

Engelhard

I. M.

Olatunji

B. O.

de Jong

P. J.

(2011). Disgust and the development of posttraumatic stress among soldiers deployed to Afghanistan. Journal of Anxiety Disorders, 25, 58–63. doi:10.1016/j.janxdis.2010.08.003

26.

Fairbrother

Newth

S. J.

Rachman

(2005). Mental pollution: Feelings of dirtiness without physical contact. Behaviour Research and Therapy, 43, 121–130. doi:10.1016/j.brat.2003.12.005

27.

Fairbrother

Rachman

(2004). Feelings of mental pollution subsequent to sexual assault. Behaviour Research and Therapy, 42, 173–189. doi:10.1016/S0005-7967(03)00108-6

28.

Feldner

M. T.

Fraia

Badour

Leen-Feldner

E. W.

Olatunji

B. O.

(2010). An empirical test of the association between disgust and sexual assault. International Journal of Cognitive Therapy, 3, 11–22.

29.

Foy

D. W.

Sipprelle

R. C.

Rueger

D. B.

Carroll

E. M.

(1984). Etiology of posttraumatic stress disorder in Vietnam veterans: Analysis of premilitary, military, and combat exposure influences. Journal of Consulting and Clinical Psychology, 52, 79–87.

30.

Garcia

Kimeldorf

D. J.

Koelling

R. A.

(1955). Conditioned aversion to saccharin resulting from exposure to gamma radiation. Science, 122, 157–158.

31.

Gould

S. J.

(1997). The exaptive excellence of spandrels as a term and prototype. Proceedings of the National Academy of Sciences, USA, 94, 10750–10755.

32.

Haidt

McCauley

Rozin

(1994). Individual differences in sensitivity to disgust: A scale sampling seven domains of disgust elicitors. Personality and Individual Differences, 16, 701–713. doi:10.1016/0191-8869(94)90212-7

33.

Haidt

Rozin

McCauley

C. R.

(1997). Body, psyche, and culture: The relationship between disgust and morality. Psychology and Developing Societies, 9, 107–131.

34.

Harris

A. A.

Romer

A. L.

Hanna

E. K.

Keeling

L. A.

LaBar

K. S.

Sinnott-Armstrong

. . . Zucker

N. L.

(2019). The central role of disgust in disorders of food avoidance. International Journal of Eating Disorders, 52, 543–553.

35.

Harris

L. T.

Fiske

S. T.

(2007). Social groups that elicit disgust are differentially processed in mPFC. Social Cognitive and Affective Neuroscience, 2, 45–51. doi:10.1093/scan/nsl037

36.

Harrison

N. A.

Gray

M. A.

Gianaros

P. J.

Critchley

H. D.

(2010). The embodiment of emotional feelings in the brain. The Journal of Neuroscience, 30, 12878–12884. doi:10.1523/JNEUROSCI.1725-10.2010

37.

Hathaway

L. M.

Boals

Banks

J. B.

(2009). PTSD symptoms and dominant emotional response to a traumatic event: An examination of DSM–IV Criterion A2. Anxiety, Stress, & Coping, 23, 119–126. doi:10.1080/10615800902818771

38.

Insel

Cuthbert

Garvey

Heinssen

Pine

Quinn

. . . Wang

(2010). Research Domain Criteria (RDoC): Toward a new classification framework for research on mental disorders. American Journal of Psychiatry, 167, 748–751. doi:10.1176/appi.ajp.2010.09091379

39.

Kelly

D. R.

(2011). Yuck! The nature and moral significance of disgust. Cambridge, MA: MIT Press.

40.

Krzanowska

Kuleta

(2017). From anxiety to compulsivity—A review of changes to OCD classification in DSM-5 and ICD-11. Archives of Psychiatry and Psychotherapy, 19, 7–15. doi:10.12740/APP/76150

41.

Kupfer

(2018). Why are injuries disgusting? Comparing pathogen avoidance and empathy accounts. Emotion, 18, 959–970.

42.

Lieberman

Patrick

(2018). Objection: Disgust, morality, and the law. New York, NY: Oxford University Press.

43.

McKay

(2006). Treating disgust reactions in contamination-based obsessive-compulsive disorder. Journal of Behavior Therapy and Experimental Psychiatry, 37, 53–59. doi:10.1016/j.jbtep.2005.09.005

44.

McKay

Moretz

M. W.

(2009). The intersection of disgust and contamination fear. In Olatunji

B. O.

McKay

(Eds.), Disgust and its disorders: Theory, assessment, and treatment implications (pp. 211–227). Washington, DC: American Psychological Association.

45.

McKeever

V. M.

Huff

M. E.

(2003). A diathesis-stress model of posttraumatic stress disorder: Ecological, biological, and residual stress pathways. Review of General Psychology, 7, 237–250. doi:10.1037/1089-2680.7.3.237

46.

Meehl

P. E.

(1962). Schizotaxia, schizotypy, schizophrenia. American Psychologist, 17, 827–838.

47.

Melli

Gremigni

Elwood

L. S.

Stopani

Bulli

Carraresi

(2015). The relationship between trait guilt, disgust propensity, and contamination fear. International Journal of Cognitive Therapy, 8, 193–205.

48.

Moretz

M. W.

McKay

(2008). Disgust sensitivity as a predictor of obsessive-compulsive contamination symptoms and associated cognitions. Journal of Anxiety Disorders, 22, 707–715. doi:10.1016/j.janxdis.2007.07.004

49.

Nesse

R. M.

(1990). Evolutionary explanations of emotions. Human Nature, 1, 261–289.

50.

Nesse

R. M.

(2001). How is Darwinian medicine useful? Western Medicine Journal, 174, 358–359.

51.

Nesse

R. M.

Williams

G. C.

(1994). Why we get sick: The new science of Darwinian medicine. New York, NY: Vintage Books.

52.

Nussbaum

M. C.

(2010). From disgust to humanity: Sexual orientation and constitutional law. New York, NY: Oxford University Press.

53.

O’Donnell

M. L.

Creamer

McFarlane

A. C.

Silove

Bryant

R. A.

(2010). Should A2 be a diagnostic requirement for posttraumatic stress disorder in DSM-V? P sychiatry Research, 176, 257–260. doi:10.1016/j.psychres.2009.05.012

54.

Ojserkis

McKay

Badour

C. L.

Feldner

M. T.

Arocho

Dutton

(2014). Alleviation of moral disgust, shame, and guilt in posttraumatic stress reactions: An evaluation of comprehensive distancing. Behavior Modification, 38, 801–836. doi:10.1177/0145445514543465

55.

Olatunji

B. O.

Armstrong

Elwood

(2017). Is disgust proneness associated with anxiety and related disorders? A qualitative review and meta-analysis of group comparison and correlational studies. Perspectives on Psychological Science, 12, 613–648. doi:10.1177/1745691616688879

56.

Olatunji

B. O.

Babson

K. A.

Smith

R. C.

Feldner

M. T.

Connolly

K. M.

(2009). Gender as a moderator of the relation between PTSD and disgust: A laboratory test employing individualized script-driven imagery. Journal of Anxiety Disorders, 23, 1091–1097. doi:10.1016/j.janxdis.2009.07.012

57.

Olatunji

B. O.

Ebesutani

Haidt

Sawchuk

C. N.

(2014). Specificity of disgust domains in the prediction of contamination anxiety and avoidance: A multimodal examination. Behavior Therapy, 45, 469–481. doi:10.1016/j.beth.2014.02.006

58.

Olatunji

B. O.

Ebesutani

Kim

E. H.

(2015). Examination of a bifactor model of the Three Domains of Disgust Scale: Specificity in relation to obsessive-compulsive symptoms. Psychological Assessment, 27, 102–113. doi:10.1037/pas0000039

59.

Olatunji

B. O.

Ebesutani

Kim

E. H.

(2016). Does the measure matter? On the association between disgust proneness and OCD symptoms. Journal of Anxiety Disorders, 44, 63–72. doi:10.1016/j.janxdis.2016.10.010

60.

Olatunji

B. O.

Haidt

McKay

David

(2008). Core, animal reminder, and contamination disgust: Three kinds of disgust with distinct personality, behavioral, physiological, and clinical correlates. Journal of Research in Personality, 42, 1243–1259. doi:10.1016/j.jrp.2008.03.009

61.

Olatunji

B. O.

Lohr

J. M.

Sawchuk

C. N.

Tolin

D. F.

(2007). Multimodal assessment of disgust in contamination-related obsessive-compulsive disorder. Behaviour Research and Therapy, 45, 263–276. doi:10.1016/j.brat.2006.03.004

62.

Olatunji

B. O.

McKay

(2007). Disgust and psychiatric illness: Have we remembered? British Journal of Psychiatry, 190, 457–459. doi:10.1192/bjp.bp.106.032631

63.

Olatunji

B. O.

McKay

(2009). Disgust and its disorders: Theory, assessment, and treatment implications. Washington, DC: American Psychological Association.

64.

Olatunji

B. O.

Moretz

M. W.

Wolitzky-Taylor

K. B.

McKay

McGrath

P. B.

Ciesielski

B. G.

(2010). Disgust vulnerability and symptoms of contamination-based OCD: Descriptive tests of incremental specificity. Behavior Therapy, 41, 475–490. doi:10.1016/j.beth.2009.11.005

65.

Olatunji

B. O.

Sawchuk

C. N.

(2005). Disgust: Characteristic features, social manifestations, and clinical implications. Journal of Social and Clinical Psychology, 24, 932–962. doi:10.1521/jscp.2005.24.7.932

66.

Olatunji

B. O.

Sawchuk

C. N.

de Jong

P. J.

Lohr

J. M.

(2006). The structural relation between disgust sensitivity and blood-injection-injury fears: A cross-cultural comparison of US and Dutch data. Journal of Behavior Therapy and Experimental Psychiatry, 37, 16–29. doi:10.1016/j.jbtep.2005.09.002

67.

Olatunji

B. O.

Sawchuk

C. N.

de Jong

P. J.

Lohr

J. M.

(2007). Disgust sensitivity and anxiety disorder symptoms: Psychometric properties of the Disgust Emotion Scale. Journal of Psychopathology and Behavioral Assessment, 29, 115–124. doi:10.1007/s10862-006-9027-8

68.

Olatunji

B. O.

Sawchuk

C. N.

Lohr

J. M.

de Jong

P. J.

(2004). Disgust domains in the prediction of contamination fear. Behaviour Research and Therapy, 42, 93–104. doi:10.1016/S0005-7967(03)00102-5

69.

Olatunji

B. O.

Tolin

D. F.

Huppert

J. D.

Lohr

J. M.

(2005). The relation between fearfulness, disgust sensitivity and religious obsessions in a non-clinical sample. Personality and Individual Differences, 38, 891–902. doi:10.1016/j.paid.2004.06.012

70.

Olatunji

B. O.

Williams

N. L.

Lohr

J. M.

Sawchuk

C. N.

(2005). The structure of disgust: Domain specificity in relation to contamination ideation and excessive washing. Behaviour Research and Therapy, 43, 1069–1086. doi:10.1016/j.brat.2004.08.002

71.

Olatunji

B. O.

Williams

N. L.

Sawchuk

C. N.

Lohr

J. M.

(2006). Disgust, anxiety and fainting symptoms associated with blood-injection-injury fears: A structural model. Journal of Anxiety Disorders, 20, 23–41. doi:10.1016/j.janxdis.2004.11.009

72.

Olatunji

B. O.

Williams

N. L.

Tolin

D. F.

Abramowitz

J. S.

Sawchuk

C. N.

Lohr

J. M.

Elwood

L. S.

(2007). The Disgust Scale: Item analysis, factor structure, and suggestions for refinement. Psychological Assessment, 19, 281–297. doi:10.1037/1040-3590.19.3.281

73.

Ost

L. G.

(1992). Blood and injection phobia: Background and cognitive, physiological, and behavioral variables. Journal of Abnormal Psychology, 101, 68–74. doi:10.1037/0021-843X.101.1.68

74.

Page

A. C.

(1994). Blood-injury phobia. Clinical Psychology Review, 14, 443–461.

75.

Page

A. C.

(2003). The role of disgust in faintness elicited by blood and injection stimuli. Anxiety Disorders, 17, 45–58.

76.

Phillips

M. L.

Fahy

David

A. S.

Senior

(1998). Disgust: The forgotten emotion of psychiatry. British Journal of Psychiatry, 172, 373–375.

77.

Poli

Melli

Radomsky

A. S.

(2019). Different disgust domains specifically relate to mental and contact contamination fear in obsessive-compulsive disorder: Evidence from a path analytic model in an Italian clinical sample. Behavior Therapy, 50, 380–394.

78.

Power

M. J.

Fyvie

(2013). The role of emotion in PTSD: Two preliminary studies. Behavioural and Cognitive Psychotherapy, 41, 162–172. doi:10.1017/S1352465812000148

79.

Rottman

(2018). The social origins of disgust. In Strohminger

Kumar

(Eds.), The moral psychology of disgust (pp. 27–52). London, England: Rowman & Littlefield International.

80.

Rozin

Fallon

A. E.

(1987). A perspective on disgust. Psychological Review, 94, 23–41. doi:10.1037/0033-295X.94.1.23

81.

Rozin

Haidt

(2013). The domains of disgust and their origins: Contrasting biological and cultural evolutionary accounts. Trends in Cognitive Sciences, 17, 367–368. doi:10.1016/j.tics.2013.06.001

82.

Rozin

Haidt

McCauley

C. R.

(2008). Disgust. In Lewis

Haviland-Jones

J. M.

Feldman Barrett

(Eds.), Handbook of emotions (2nd ed., pp. 757–776). New York, NY: Guilford Press.

83.

Sawchuk

C. N.

Lohr

J. M.

Tolin

D. F.

Lee

T. C.

Kleinknecht

R. A.

(2000). Disgust sensitivity and contamination fears in spider and blood-injection-injury phobias. Behaviour Research and Therapy, 38, 753–762. doi:10.1016/S0005-7967(99)00093-5

84.

Sawchuk

C. N.

Lohr

J. M.

Westendorf

D. H.

Meunier

S. A.

Tolin

D. F.

(2002). Emotional responding to fearful and disgusting stimuli in specific phobics. Behaviour Research and Therapy, 40, 1031–1046. doi:10.1016/S0005-7967(01)00093-6

85.

Schnall

Haidt

Clore

G. L.

Jordan

A. H.

(2008). Disgust as embodied moral judgment. Personality and Social Psychology Bulletin, 34, 1096–1109. doi:10.1177/0146167208317771

86.

Shin

L. M.

McNally

R. J.

Kosslyn

S. M.

Thompson

W. L.

Rauch

S. L.

Alpert

N. M.

. . . Pitman

R. K.

(1999). Regional cerebral blood flow during script-driven imagery in childhood sexual abuse-related PTSD: A PET investigation. American Journal of Psychiatry, 156, 575–584.

87.

Simon

Meuret

A. E.

Ritz

(2017). Sympathetic and parasympathetic cardiac responses to phobia-relevant and disgust-specific emotion provocation in blood-injection-injury phobia with and without fainting history. Psychophysiology, 54, 1512–1527. doi:10.1111/psyp.12900

88.

Tolin

D. F.

Lohr

J. M.

Sawchuk

C. N.

Lee

T. C.

(1997). Disgust and disgust sensitivity in blood-injection-injury and spider phobia. Behaviour Research and Therapy, 35, 949–953. doi:10.1016/S0005-7967(97)00048-X

89.

Tolin

D. F.

Woods

C. M.

Abramowitz

J. S.

(2006). Disgust sensitivity and obsessive–compulsive symptoms in a non-clinical sample. Journal of Behaviour Therapy and Experimental Psychiatry, 37, 30–40. doi:10.1016/j.jbtep.2005.09.003

90.

Tolin

D. F.

Worhunsky

Maltby

(2004). Sympathetic magic in contamination-related OCD. Journal of Behavior Therapy and Experimental Psychiatry, 35, 193–205.

91.

Tooby

(1985). The emergence of evolutionary psychology. In Pines

(Ed.), Emerging syntheses in science (pp. 1–5). Santa Fe, NM: Santa Fe Institute. doi:10.1109/LMWC.2010.2104138

92.

Tooby

Cosmides

(2008). The evolutionary psychology of the emotions and their relationship to internal regulatory variables. In Lewis

Haviland-Jones

J. M.

Feldman Barrett

(Eds.), Handbook of emotions (3rd ed., pp. 114–137). New York, NY: Guilford Press.

93.

Tybur

J. M.

Lieberman

Griskevicius

(2009). Microbes, mating, and morality: Individual differences in three functional domains of disgust. Journal of Personality and Social Psychology, 97, 103–122. doi:10.1037/a0015474

94.

Tybur

J. M.

Lieberman

Kurzban

DeScioli

(2013). Disgust: Evolved function and structure. Psychological Review, 120, 65–84. doi:10.1037/a0030778

95.

Van Delft

Finkenauer

Tybur

J. M.

Lamers-Winkelman

. (2016). Disgusted by sexual abuse: Exploring the association between disgust sensitivity and posttraumatic stress symptoms among mothers of sexually abused children. Journal of Traumatic Stress, 29, 237–244. doi:10.1002/jts

96.

Van Overveld

W. J. M.

de Jong

P. J.

Peters

M. L.

Cavanagh

Davey

G. C. L

. (2006). Disgust propensity and disgust sensitivity: Separate constructs that are differentially related to specific fears. Personality and Individual Differences, 41, 1241–1252. doi:10.1016/j.paid.2006.04.021

97.

Viar

M. A.

Etzel

E. N.

Ciesielski

B. G.

Olatunji

B. O.

(2010). Disgust, anxiety, and vasovagal syncope sensations: A comparison of injection-fearful and nonfearful blood donors. Journal of Anxiety Disorders, 24, 941–945. doi:10.1016/j.janxdis.2010.06.021

98.

Vrana

S. R.

(1993). The psychophysiology of disgust: Differentiating negative emotional contexts with facial EMG. Psychophysiology, 30, 279–286. doi:10.1111/j.1469-8986.1993.tb03354.x

99.

Weidmann

Conradi

Gröger

Fehm

Fydrich

(2009). Using stressful films to analyze risk factors for PTSD in analogue experimental studies—Which film works best? Anxiety, Stress, and Coping, 22, 549–569. doi:10.1080/10615800802541986

100.

Woody

S. R.

Tolin

D. F.

(2002). The relationship between disgust sensitivity and avoidant behavior: Studies of clinical and nonclinical samples. Anxiety Disorders, 16, 543–559.