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The validity of DSM-IV-TR criteria B and C of hair-pulling disorder (trichotillomania): Evidence from a clinical study
Psychiatry Research 189 (2011) 276–280
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Psychiatry Research j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / p s yc h r e s
The validity of DSM-IV-TR criteria B and C of hair-pulling disorder (trichotillomania): Evidence from a clinical study Christine Lochner a,⁎, Dan J. Stein a, b, Douglas Woods c, David L. Pauls d, e, Martin E. Franklin f, Elizabeth H. Loerke d, e, Nancy J. Keuthen e a
MRC Unit on Anxiety & Stress Disorders, Department of Psychiatry, University of Stellenbosch, Tygerberg, South Africa Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA d Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA e Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA f Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA b c
a r t i c l e
i n f o
Article history: Received 12 January 2011 Received in revised form 6 July 2011 Accepted 11 July 2011 Keywords: Trichotillomania Diagnostic criteria DSM Hair-pulling
a b s t r a c t In both DSM-IV-TR and the ICD-10, hair-pulling disorder (trichotillomania, or TTM) is described as hairpulling, with a rising urge or tension prior to pulling or when attempting to resist, and pleasure, relief or gratification during or after pulling. However, it has been questioned whether all patients with hair-pulling experience these other phenomena, and whether they occur with all pulling episodes. The objective of this study was to examine the DSM-IV-TR requirement of criteria B and C for a diagnosis of TTM in a sample of people with hair-pulling. A multi-site sample of adults with hair-pulling who met both DSM-IV-TR diagnostic criteria B and C (n = 82, 89.13%) were compared to those who failed to satisfy both B and C (n = 10, 10.87%) on a number of clinical variables. There were no differences in hair-pulling severity, levels of comorbid depressive and anxiety symptoms, number of comorbid body-focused repetitive behaviors, or impairment between those patients who did and did not meet criteria B and C. Our study does not provide convincing support for the inclusion of the current diagnostic criteria B and C for TTM in DSM-5. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Hair-pulling disorder (trichotillomania, or TTM) is increasingly recognized as a serious condition, given its relatively high prevalence (Duke et al., 2010), significant comorbidity with psychiatric disorders such as depression, obsessive–compulsive disorder and Tourette's syndrome, and associated impairment (Woods et al., 2006). The medical complications of TTM are relatively uncommon but can be serious; these include gastrointestinal obstruction and even death (Muller, 1987; O'Sullivan et al., 1996; Bouwer and Stein, 1998). In 1987, TTM was included in the Diagnostic and Statistical Manual of Mental Disorders 3rd edition (revised version, or DSM-III-R) (American Psychiatric Association, 1987) as an impulse control disorder not elsewhere classified. TTM remained in this category in DSM-IV and DSM-IV-TR but the diagnostic criteria included a revised version of criterion B (i.e. the experience of tension prior to hair-pulling or when
⁎ Corresponding author. PO Box 19063, Tygerberg, 7505, South Africa. Tel.: + 27 21 938 9179; fax: + 27 21 933 5790. E-mail address: [email protected] (C. Lochner). 0165-1781/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2011.07.022
attempting to resist the behavior) and E (clinically significant distress and/or impairment) (American Psychiatric Association, 1994; American Psychiatric Association, 2000) (Appendix 1). In the 10th edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) (World Health Organization, 1992), TTM was included in the section on disorders of adult personality and behavior, where it was classified as one of the habit and impulse disorders (Appendix 2). Research on TTM has increased significantly in the last 20 years. It has been argued recently (Stein et al., 2010) that it is timely to assess whether the reliability, validity, and clinical utility of current diagnostic criteria for TTM can be improved, and whether the categorization of TTM as an impulse control disorder is optimal. In particular, the validity and utility of criteria B and C of DSM-IV-TR (i.e. rising tension prior to or when attempting to resist pulling, and pleasure, relief or gratification during or subsequent to pulling) have been questioned. These criteria were originally intended to be consistent with TTM's grouping in the Impulse Control Disorders category. Troubling, however, is the research suggesting that approximately 20% of patients with clinically meaningful hair-pulling do not report either an increasing sense of tension or a sense of pleasure/gratification/relief related to hair-pulling (Christenson and Mansueto, 1999; du Toit et al., 2001). In the more recent
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Trichotillomania Impact Project-Adults (TIP-A), an internet survey of 2268 persons with self-reported hair-pulling (Woods et al., 2006), it was found that the symptoms of tension before pulling or accompanying efforts to resist, and subsequent pleasure/relief/gratification, were quite common in people with hair-pulling. However, these internal experiences were not reported by all individuals with impairment-producing hair-pulling and, when they were present, did not necessarily occur prior to and/or after all pulling episodes. Very few studies have compared individuals meeting full criteria for DSM-IV TTM and those not meeting B and C. In a preliminary study at the MRC Unit on Anxiety and Stress Disorders (South Africa) including 47 participants with hair-pulling, few significant differences between those who met criteria B and C and those without these symptoms were found (du Toit et al., 2001). In a recent follow-up study, Lochner et al. found that 27.5% of 80 participants with chronic hair-pulling did not meet either criteria B or C (Lochner et al., 2010). A few differences were noted between participants meeting both criteria B and C and those not meeting these criteria, but none seemed clinically significant. There also were no significant differences between the two groups in terms of age, gender, age of onset, duration and severity of hair-pulling. Similarly, the TIP-A study (which did not analyze differences in hair-pulling sites and behaviors related to hair-pulling) found that subjects who met criteria B and C (endorsing both symptoms at least “a little of the time”; n = 1616) vs. those not meeting both B and C (n = 92) did not differ in hair-pulling severity, levels of depression and anxiety and impairment (Woods et al., unpublished data; Stein et al., 2010). Thus, while present at some level in most people with hair pulling, TIP-A data suggest criteria B and C are not indicative of increased pulling severity, impairment or psychological symptoms of depression and anxiety. Given the above findings, inclusion of B and C as required diagnostic criteria for the disorder can be questioned. The large TIP-A study, however, suffers the limitations associated with an internet survey, the most prominent of which is the lack of faceto-face diagnostic ascertainment. In the present study, we aimed to overcome these limitations. We used some of the questionnaires from the TIP-A study and conducted a similar analysis but used a combined sample of patients with hair-pulling from South Africa and the USA that had in-person clinical assessments. We compared patients meeting TTM criteria B and C, and those who did not satisfy both B and C, on a number of relevant clinical variables, including hair-pulling severity, levels of depression, anxiety and stress, number of comorbid body-focused repetitive behaviors and functional impairment.
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2.2. Interview measures For our study analyses, we used data obtained from questions on the Trichotillomania Impact Survey (TIS: Woods et al., 2006); i.e. more specifically, whether patients experienced an increased physical tension or an “urge” immediately before pulling or when attempting to resist pulling and whether they experienced a sense of pleasure/ gratification/relief after pulling. The Trichotillomania Diagnostic Interview-Revised (TDI-R) is an updated version of the TDI (Rothbaum and Ninan, 1994), a clinician-based, semi-structured interview modeled after the SCID. The TDI consists of 3-point ratings of responses to items assessing the DSM-III R diagnostic criteria for TTM and the TDI-R includes revisions to ensure conformity with DSM-IV-TR updated criteria for TTM. The TDI-R was utilized to determine if study participants satisfied full DSM-IV-TR diagnostic criteria for TTM. In addition, three other measures with acceptable psychometric properties were used to assess severity of hair-pulling (i.e. the Massachusetts General Hospital Hairpulling Scale (MGH-HPS) (Keuthen et al., 1995)), severity of depression and anxiety symptoms (i.e. the Depression Anxiety Stress Scale-21-Item version (DASS-21) (Lovibond and Lovibond, 1995)), and impairment (i.e. the Sheehan Disability Scale (SDS) (Sheehan et al., 1996)), respectively. The MGH-HPS is a seven-item patient-rated scale used as the primary measure of hair-pulling symptom severity. MGH-HPS items focus on respondents' ratings of the frequency and intensity of their urges to pull, their ability to control these urges, the frequency of actual hair-pulling, the frequency of attempts to resist pulling, their ability to control their pulling, and their level of associated distress. The MGH-HPS demonstrates good internal consistency (Keuthen et al., 1995), excellent test–retest reliability, strong convergent and divergent validity and sensitivity to change in hairpulling symptoms (O'Sullivan et al., 1995). The DASS-21 is a 21-item scale designed to measure symptoms of depression, anxiety, and stress in clinical and non-clinical populations. The measure provides separate scores for the empirically derived factors. Each of the three factors consists of seven items measured on a 4-point Likert scale ranging from 0 (“did not apply to me at all”) to 3 (“applied to me very much, or most of the time”). Scores on each subscale are calculated by summing the scores on the seven items and multiplying this by two; thus, each scale has a minimum score of 0 and a maximum score of 42, with higher scores indicative of more frequent symptoms in a given domain. Each subscale has demonstrated good psychometric properties (Brown et al., 1997). The SDS is a three-item self-report scale assessing current impairment in work activities, social life and leisure activities, and family life and home responsibilities due to emotional symptoms (Sheehan et al., 1996). On the SDS, individuals rate the degree to which their symptoms have impaired each area of life on a scale from 0 to 10 (0 = not at all, 1–3 = mildly, 4–6 = moderately, 7–9 = markedly, 10 = very severely), and the three item ratings are added together to create a total disability score (range = 0–30). The SDS demonstrates good internal consistency (alpha coefficients ranging from 0.56 to 0.86 in untreated and treated patients with panic disorder (Leon et al., 1992) and social phobia (Olfson et al., 1996)). The number of comorbid body-focused repetitive behaviors (BFRBs) were measured based on one of the TIS questions which assesses whether the individual engaged in skin-picking, nose-picking, nail-biting, lip-/cheek-biting or any other damaging BFRBs. The number of BFRBs each individual endorsed was entered into the analyses, and not the specific BFRB. For example, if an individual endorsed skin-picking and nail-biting, the figure ‘2’ would have been entered as the BFRB data point for that individual.
2. Methods
2.3. Data analyses
This project was a joint venture between researchers from the Massachusetts General Hospital/Harvard Medical School, Boston (USA) and the MRC Unit on Anxiety & Stress Disorders, University of Stellenbosch (South Africa). The study was approved by the Institutional Review Boards of the participating sites and conducted in accordance with the guidelines of the Declaration of Helsinki (Edinburgh 2000) on the ethical conduct of research studies in humans. All patients gave written informed consent for research participation.
Patients endorsing criteria B and C (i.e. those endorsing both symptoms at least “a little of the time” according to the TIS questions) were compared to those not endorsing both B and C, using chi-square for categorical variables (e.g. gender), and student t-tests and Mann–Whitney U tests for continuous variables (e.g. severity scores). Z scores were used to identify possible outliers on interview measures. Analyses were run for each variable, both with and without outliers (if applicable). The presence/absence of outliers, and the respective scores were reported for each measure. P-values less than 0.05 were considered to be significant.
2.1. Participants
3. Results
Patients interviewed at the MRC Unit on Anxiety and Stress Disorders were recruited by physician referral, media advertisements and the Mental Health Information Centre of South Africa. Interviews were done by a clinical psychologist or other mental health practitioner (i.e. a psychiatric nurse, general medical practitioner, or psychiatrist) with expertise in the field. All participants reported hair-pulling and fulfilled at least criteria A, D and E of DSM-IV and DSM-IV-TR for TTM on the Structured Clinical Interview for Axis I Disorders–Patient version (SCID-I/P) (First et al., 1998) (MRC Unit). Patients interviewed at Massachusetts General Hospital were recruited for a genetics research project by clinician referral, flyers, and the Trichotillomania Learning Center. Interviews were conducted by study staff who were trained to an acceptable reliability criterion level on all clinician-administered interviews/scales. All participants reported hair-pulling and fulfilled at least criteria A, D, and E of DSM-IV/DSM-IVTR for TTM. Individuals diagnosed with mental retardation, autism spectrum disorders, or psychotic disorders were excluded.
3.1. Demographics The total sample consisted of 28 South African and 64 sex- and age-matched American hair-pullers. The demographic characteristics of participants are summarized in Table 1. Ninety-two (n = 92) participants completed the TIS questions addressing whether they experienced an increased physical tension or an “urge” immediately before pulling or when attempting to resist pulling (B) and whether they experienced a sense of pleasure/ gratification/relief after pulling (C). There were 86 (93.48%) individuals who reported increased physical tension or an “urge” immediately
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Table 1 Demographic characteristics of each group. Variables
Gender
Participants
Male Female
Mean age (S.D.) a
Statistic
Meeting criteria B and C for TTM at least “a little of the time”a (n = 82; 89.13%)
Not meeting criteria B and C for TTMa (n = 10; 10.87%)
p-value
5 77 (86.5%) 34.6 (12.6) years
0 10 35.2 (9.0) years
χ2 = 1.2, p = 0.3 t = 0.1, p = 0.9
From the TIS.
before pulling or when trying to resist pulling at least a little of the time. Six (6.52%) individuals reported that they never/almost never experienced these symptoms. Almost all of the participants (n = 87, 94.57%) indicated that they experienced a sense of pleasure/gratification/relief after pulling at least a little of the time. Four (4.35%) participants reported never/almost never experiencing these emotions after pulling. According to responses to the TIS, there were 82 (89.1%) participants who met both criteria B and C, and 10 (10.87%) who did not meet both these criteria. There was one (1.1%) participant who reported that she “did not know” whether or not he/she experienced a sense of pleasure/gratification/relief after pulling. Although the comparison groups were created based on the TIS, participants' responses to the TDI-R yielded similar data regarding endorsement of criteria B and C. Eighty-nine of the 92 that completed the TIS questions also completed this scale. There were 77 (86.52%) participants who met both criteria B and C of DSM-IV-TR TTM and 12 (13.48%) who did not meet both these criteria. 3.2. Clinical variables Not all participants that were interviewed completed all of the study scales. We include the numbers of participants who completed each of the MGH-HPS, DASS, and the SDS, respectively, in Table 2. Also see Table 2 for a comparison of those who did (n = 82) and those who did not (n = 10) meet Criteria B and C on these measures (according to the TIS) including outlier data points. 3.2.1. Hair-pulling severity MGH-HPS total scores ranged from 0 to 24 with a mean (S.D.) of 14.8 (4.37). Comparison of the two groups (both with and without the
one outlier) revealed no significant group difference in hair-pulling severity. 3.2.2. Depression, anxiety and stress In the total sample, depression scores on the DASS ranged from 0 to 36 and the mean score was 8.03 (S.D. = 9.0). The anxiety scores ranged from 0 to 24 and the mean was 4.17 (S.D. = 5.69). Stress scores on the DASS ranged from 0 to 38 with a mean score of 10.89 (S.D. = 9.46). The DASS anxiety subscale had two outliers. Analyses of DASS subscale scores both with and without the outliers revealed no significant differences between participants meeting both DSM-IV-TR TTM criteria B and C vs. those who did not satisfy both B and C. In a subsequent analysis, DASS anxiety subscale scores were transformed to correct for skewness; comparison analyses still failed to show group differences. 3.2.3. Other body-focused repetitive behaviors (BFRBs) Participants meeting DSM-IV-TR TTM criteria B and C (n = 68; mean = 0.81, S.D. = 0.87) did not differ significantly from those without B and C (n = 11; mean = 0.91, S.D. = 1.04) regarding the number of BFRBs that were endorsed (t = − 0.345, p = 0.731). 3.2.4. Functional impairment SDS disability scores for the entire sample ranged from 1 to 10 for work and social domains and from 1 to 8 for the home domain. Mean scores (S.D.) were 2.64 (1.93), 3.84 (2.26) and 2.41 (1.81) on the work, social and home domains, respectively. The SDS work subscale had one outlier. No significant group differences were reported on any of the SDS subscale scores for analyses with and without outliers when comparing those who did and did not meet criteria B and C.
Table 2 Comparison of TTM patients who did and did not meet DSM-IV-TR criteria B and C for TTM on several measures of clinical phenomenology. Variables
Participants
Statistics
Meeting criteria B and C for TTM “at least a little of the time”a Not meeting criteria B and C for TTMa MGH-HPS—total mean (S.D.)
n = 71: 15.08 (4.13) (no outliers)
DASS—depression mean (S.D.) n = 63: 8.31 (9.07) (no outliers) DASS—anxiety mean (S.D.) n = 63: 4.22 (5.74) (with outliers); n = 61: 3.57 (4.53) (without outliers) DASS—stress mean (S.D.) n = 63: 11.05 (9.62) (no outliers) SDS—work mean (S.D.) n = 69: 2.74 (1.97) (with outlier); n = 68: 2.63 (1.77) (without outlier) SDS—social mean (S.D.) n = 69: 3.91 (2.32) (no outliers) SDS—home mean (S.D.) n = 69: 2.48 (1.88) (no outliers) a
From the TIS.
n = 12: 13.08 (5.45) (with outlier); n = 11: 14.27 (3.74) (without outlier) n = 9: 6.0 (8.77) (no outliers) n = 9: 3.78 (5.70) (no outliers)
t = 1.5, p = 0.1 (with one outlier); t = 0.6, p = 0.5 (without outlier)
n = 9: 9.78 (8.74) (no outliers) n = 11: 2.0 (1.61) (no outliers)
t = 0.4; p = 0.7
n = 11: 3.36 (1.91) (no outliers) n = 11: 2.0 (1.34) (no outliers)
t = 0.7, p = 0.5
t = 0.7, p = 0.5 t = 0.2, p = 0.8 (with two outliers); t = − 0.1 p = 0.9 (without outliers)
t = 1.2, p = 0.2 (with outlier); t = 1.1, p = 0.3 (without outlier)
t = 0.8, p = 0.4
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Similar to the DASS analyses, we transformed the SDS work subscale to correct for the skewness; analyses with the corrected score also did not render significant differences between the two groups in terms of work impairment. 4. Discussion Examination of the DSM-IV-TR requirement of criteria B and C for a diagnosis of TTM in a large sample of hair-pullers who underwent structured clinical interviews indicated that most individuals reported increased physical tension or an “urge” immediately before pulling or when trying to resist pulling, and a sense of pleasure/gratification/ relief after pulling at least a little of the time. However, comparison of hair-pullers endorsing DSM-IV-TR TTM criteria B and C with those not endorsing both B and C revealed no significant group differences on any of the clinical variables assessed. The findings here suggest that in adult patients with current hairpulling, meeting criteria B and C does not appear to influence hairpulling severity, comorbid symptom severity, number of comorbid body-focused repetitive behaviors or impairment. The present study focused on one aspect of a previous investigation aimed at identifying key TTM subtypes (Lochner et al., 2010). However, the present study included patients from more sites, was done in a larger sample of individuals with hair-pulling, and implemented a different way of splitting the sample. Nevertheless, both studies reported similar findings — i.e. no significant group differences. The present findings are also similar to those found in the TIP-A study. In addition, keeping criteria B and C in the diagnostic set for hair-pulling disorder (TTM) may mean that 10% or more of affected cases may be “missed” or not diagnosed. Taken together, these data thus seem to suggest that criteria B and C for TTM should be omitted from DSM-5. However, there are some ideas for the replacement of criteria B and C in DSM-5 that merit consideration. In particular, criteria B and C convey the characteristic driven nature of pulling, i.e. that the person keeps pulling and is unable to stop, and so may be useful in a differential diagnosis. A monothetic criteria set, without criteria B and C, and focused only on hair-pulling per se, might create the impression of TTM as a single symptom, ignoring the fact that TTM is a syndrome with typical features. Further research to determine whether words such as “urge”, or alternative phrases such as “seemingly driven” are reliable and useful additions to the criteria set, is needed. Literature on other disorders of impulse-control, and addictive or body-focused stereotypic disorders with urge/tension and pleasure/relief/gratification “symptoms” similar to those seen in TTM, may also be useful in the search for suitable alternatives to the current diagnostic criteria. Future studies that include a comparison between patients with and without criterion B, and then between those meeting and those not meeting criterion C, may also contribute to the debate. There are a few limitations to this investigation that need consideration. The current study was done in a relatively small sample of patients. Future studies may benefit from inclusion of a larger sample, particularly in the group not meeting criteria B and C in particular. The unequal sample size of the comparison groups (more specifically, the small size of the one group) may have led to low statistical power and a subsequent lack of significant group differences. Instances where the pvalues were small but failed to denote significant group differences may thus have been the result of low statistical power. A type II error, or false negative, can thus not be ruled out here. Second, it is possible that meaningful differences between the groups would have emerged with different dependent variables. For example, variables not measured in this study such as family data, genetic data, or comprehensive treatment response data may have been predicted by those who did and did not meet criteria B and C for TTM. Although the samples from the USA and SA were age- and sex-matched, not analyzing other possible differences (e.g. in terms of psychiatric comorbidity) can be considered a limitation. While we compared patients from the combined sample with/out
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criteria B and C on their levels of depression, anxiety and stress, and on the number of comorbid body-focused repetitive behaviors, a more detailed comorbidity assessment and comparison of comorbid Axis Idisorders between the groups would have been useful to this investigation. Finally, the presence of outliers is another complicating factor that may have influenced statistical power. In summary, our findings do not provide convincing support for the inclusion of the current diagnostic criteria B and C for hair-pulling disorder (TTM) in DSM-5. Field trials to test the validity of proposed DSM-5 diagnostic criteria would be useful, as would the examination of other descriptors of hair-pulling urges and ‘failure to control’ symptoms. In addition, future research including monitoring of hair-pulling and associated symptoms moment by moment (i.e. exploring the specific phenomenological experiences occurring within each pulling episode) and longitudinally (i.e. exploring the typical phenomenological experiences occurring across hair-pulling episodes) may be useful to describe the nature of hair-pulling symptoms. Acknowledgments We would like to express our appreciation for the Trichotillomania Learning Center's assistance in data collection and financial support for this project.
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Psychiatry Research j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / p s yc h r e s
The validity of DSM-IV-TR criteria B and C of hair-pulling disorder (trichotillomania): Evidence from a clinical study Christine Lochner a,⁎, Dan J. Stein a, b, Douglas Woods c, David L. Pauls d, e, Martin E. Franklin f, Elizabeth H. Loerke d, e, Nancy J. Keuthen e a
MRC Unit on Anxiety & Stress Disorders, Department of Psychiatry, University of Stellenbosch, Tygerberg, South Africa Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA d Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA e Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA f Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA b c
a r t i c l e
i n f o
Article history: Received 12 January 2011 Received in revised form 6 July 2011 Accepted 11 July 2011 Keywords: Trichotillomania Diagnostic criteria DSM Hair-pulling
a b s t r a c t In both DSM-IV-TR and the ICD-10, hair-pulling disorder (trichotillomania, or TTM) is described as hairpulling, with a rising urge or tension prior to pulling or when attempting to resist, and pleasure, relief or gratification during or after pulling. However, it has been questioned whether all patients with hair-pulling experience these other phenomena, and whether they occur with all pulling episodes. The objective of this study was to examine the DSM-IV-TR requirement of criteria B and C for a diagnosis of TTM in a sample of people with hair-pulling. A multi-site sample of adults with hair-pulling who met both DSM-IV-TR diagnostic criteria B and C (n = 82, 89.13%) were compared to those who failed to satisfy both B and C (n = 10, 10.87%) on a number of clinical variables. There were no differences in hair-pulling severity, levels of comorbid depressive and anxiety symptoms, number of comorbid body-focused repetitive behaviors, or impairment between those patients who did and did not meet criteria B and C. Our study does not provide convincing support for the inclusion of the current diagnostic criteria B and C for TTM in DSM-5. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Hair-pulling disorder (trichotillomania, or TTM) is increasingly recognized as a serious condition, given its relatively high prevalence (Duke et al., 2010), significant comorbidity with psychiatric disorders such as depression, obsessive–compulsive disorder and Tourette's syndrome, and associated impairment (Woods et al., 2006). The medical complications of TTM are relatively uncommon but can be serious; these include gastrointestinal obstruction and even death (Muller, 1987; O'Sullivan et al., 1996; Bouwer and Stein, 1998). In 1987, TTM was included in the Diagnostic and Statistical Manual of Mental Disorders 3rd edition (revised version, or DSM-III-R) (American Psychiatric Association, 1987) as an impulse control disorder not elsewhere classified. TTM remained in this category in DSM-IV and DSM-IV-TR but the diagnostic criteria included a revised version of criterion B (i.e. the experience of tension prior to hair-pulling or when
⁎ Corresponding author. PO Box 19063, Tygerberg, 7505, South Africa. Tel.: + 27 21 938 9179; fax: + 27 21 933 5790. E-mail address: [email protected] (C. Lochner). 0165-1781/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2011.07.022
attempting to resist the behavior) and E (clinically significant distress and/or impairment) (American Psychiatric Association, 1994; American Psychiatric Association, 2000) (Appendix 1). In the 10th edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) (World Health Organization, 1992), TTM was included in the section on disorders of adult personality and behavior, where it was classified as one of the habit and impulse disorders (Appendix 2). Research on TTM has increased significantly in the last 20 years. It has been argued recently (Stein et al., 2010) that it is timely to assess whether the reliability, validity, and clinical utility of current diagnostic criteria for TTM can be improved, and whether the categorization of TTM as an impulse control disorder is optimal. In particular, the validity and utility of criteria B and C of DSM-IV-TR (i.e. rising tension prior to or when attempting to resist pulling, and pleasure, relief or gratification during or subsequent to pulling) have been questioned. These criteria were originally intended to be consistent with TTM's grouping in the Impulse Control Disorders category. Troubling, however, is the research suggesting that approximately 20% of patients with clinically meaningful hair-pulling do not report either an increasing sense of tension or a sense of pleasure/gratification/relief related to hair-pulling (Christenson and Mansueto, 1999; du Toit et al., 2001). In the more recent
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Trichotillomania Impact Project-Adults (TIP-A), an internet survey of 2268 persons with self-reported hair-pulling (Woods et al., 2006), it was found that the symptoms of tension before pulling or accompanying efforts to resist, and subsequent pleasure/relief/gratification, were quite common in people with hair-pulling. However, these internal experiences were not reported by all individuals with impairment-producing hair-pulling and, when they were present, did not necessarily occur prior to and/or after all pulling episodes. Very few studies have compared individuals meeting full criteria for DSM-IV TTM and those not meeting B and C. In a preliminary study at the MRC Unit on Anxiety and Stress Disorders (South Africa) including 47 participants with hair-pulling, few significant differences between those who met criteria B and C and those without these symptoms were found (du Toit et al., 2001). In a recent follow-up study, Lochner et al. found that 27.5% of 80 participants with chronic hair-pulling did not meet either criteria B or C (Lochner et al., 2010). A few differences were noted between participants meeting both criteria B and C and those not meeting these criteria, but none seemed clinically significant. There also were no significant differences between the two groups in terms of age, gender, age of onset, duration and severity of hair-pulling. Similarly, the TIP-A study (which did not analyze differences in hair-pulling sites and behaviors related to hair-pulling) found that subjects who met criteria B and C (endorsing both symptoms at least “a little of the time”; n = 1616) vs. those not meeting both B and C (n = 92) did not differ in hair-pulling severity, levels of depression and anxiety and impairment (Woods et al., unpublished data; Stein et al., 2010). Thus, while present at some level in most people with hair pulling, TIP-A data suggest criteria B and C are not indicative of increased pulling severity, impairment or psychological symptoms of depression and anxiety. Given the above findings, inclusion of B and C as required diagnostic criteria for the disorder can be questioned. The large TIP-A study, however, suffers the limitations associated with an internet survey, the most prominent of which is the lack of faceto-face diagnostic ascertainment. In the present study, we aimed to overcome these limitations. We used some of the questionnaires from the TIP-A study and conducted a similar analysis but used a combined sample of patients with hair-pulling from South Africa and the USA that had in-person clinical assessments. We compared patients meeting TTM criteria B and C, and those who did not satisfy both B and C, on a number of relevant clinical variables, including hair-pulling severity, levels of depression, anxiety and stress, number of comorbid body-focused repetitive behaviors and functional impairment.
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2.2. Interview measures For our study analyses, we used data obtained from questions on the Trichotillomania Impact Survey (TIS: Woods et al., 2006); i.e. more specifically, whether patients experienced an increased physical tension or an “urge” immediately before pulling or when attempting to resist pulling and whether they experienced a sense of pleasure/ gratification/relief after pulling. The Trichotillomania Diagnostic Interview-Revised (TDI-R) is an updated version of the TDI (Rothbaum and Ninan, 1994), a clinician-based, semi-structured interview modeled after the SCID. The TDI consists of 3-point ratings of responses to items assessing the DSM-III R diagnostic criteria for TTM and the TDI-R includes revisions to ensure conformity with DSM-IV-TR updated criteria for TTM. The TDI-R was utilized to determine if study participants satisfied full DSM-IV-TR diagnostic criteria for TTM. In addition, three other measures with acceptable psychometric properties were used to assess severity of hair-pulling (i.e. the Massachusetts General Hospital Hairpulling Scale (MGH-HPS) (Keuthen et al., 1995)), severity of depression and anxiety symptoms (i.e. the Depression Anxiety Stress Scale-21-Item version (DASS-21) (Lovibond and Lovibond, 1995)), and impairment (i.e. the Sheehan Disability Scale (SDS) (Sheehan et al., 1996)), respectively. The MGH-HPS is a seven-item patient-rated scale used as the primary measure of hair-pulling symptom severity. MGH-HPS items focus on respondents' ratings of the frequency and intensity of their urges to pull, their ability to control these urges, the frequency of actual hair-pulling, the frequency of attempts to resist pulling, their ability to control their pulling, and their level of associated distress. The MGH-HPS demonstrates good internal consistency (Keuthen et al., 1995), excellent test–retest reliability, strong convergent and divergent validity and sensitivity to change in hairpulling symptoms (O'Sullivan et al., 1995). The DASS-21 is a 21-item scale designed to measure symptoms of depression, anxiety, and stress in clinical and non-clinical populations. The measure provides separate scores for the empirically derived factors. Each of the three factors consists of seven items measured on a 4-point Likert scale ranging from 0 (“did not apply to me at all”) to 3 (“applied to me very much, or most of the time”). Scores on each subscale are calculated by summing the scores on the seven items and multiplying this by two; thus, each scale has a minimum score of 0 and a maximum score of 42, with higher scores indicative of more frequent symptoms in a given domain. Each subscale has demonstrated good psychometric properties (Brown et al., 1997). The SDS is a three-item self-report scale assessing current impairment in work activities, social life and leisure activities, and family life and home responsibilities due to emotional symptoms (Sheehan et al., 1996). On the SDS, individuals rate the degree to which their symptoms have impaired each area of life on a scale from 0 to 10 (0 = not at all, 1–3 = mildly, 4–6 = moderately, 7–9 = markedly, 10 = very severely), and the three item ratings are added together to create a total disability score (range = 0–30). The SDS demonstrates good internal consistency (alpha coefficients ranging from 0.56 to 0.86 in untreated and treated patients with panic disorder (Leon et al., 1992) and social phobia (Olfson et al., 1996)). The number of comorbid body-focused repetitive behaviors (BFRBs) were measured based on one of the TIS questions which assesses whether the individual engaged in skin-picking, nose-picking, nail-biting, lip-/cheek-biting or any other damaging BFRBs. The number of BFRBs each individual endorsed was entered into the analyses, and not the specific BFRB. For example, if an individual endorsed skin-picking and nail-biting, the figure ‘2’ would have been entered as the BFRB data point for that individual.
2. Methods
2.3. Data analyses
This project was a joint venture between researchers from the Massachusetts General Hospital/Harvard Medical School, Boston (USA) and the MRC Unit on Anxiety & Stress Disorders, University of Stellenbosch (South Africa). The study was approved by the Institutional Review Boards of the participating sites and conducted in accordance with the guidelines of the Declaration of Helsinki (Edinburgh 2000) on the ethical conduct of research studies in humans. All patients gave written informed consent for research participation.
Patients endorsing criteria B and C (i.e. those endorsing both symptoms at least “a little of the time” according to the TIS questions) were compared to those not endorsing both B and C, using chi-square for categorical variables (e.g. gender), and student t-tests and Mann–Whitney U tests for continuous variables (e.g. severity scores). Z scores were used to identify possible outliers on interview measures. Analyses were run for each variable, both with and without outliers (if applicable). The presence/absence of outliers, and the respective scores were reported for each measure. P-values less than 0.05 were considered to be significant.
2.1. Participants
3. Results
Patients interviewed at the MRC Unit on Anxiety and Stress Disorders were recruited by physician referral, media advertisements and the Mental Health Information Centre of South Africa. Interviews were done by a clinical psychologist or other mental health practitioner (i.e. a psychiatric nurse, general medical practitioner, or psychiatrist) with expertise in the field. All participants reported hair-pulling and fulfilled at least criteria A, D and E of DSM-IV and DSM-IV-TR for TTM on the Structured Clinical Interview for Axis I Disorders–Patient version (SCID-I/P) (First et al., 1998) (MRC Unit). Patients interviewed at Massachusetts General Hospital were recruited for a genetics research project by clinician referral, flyers, and the Trichotillomania Learning Center. Interviews were conducted by study staff who were trained to an acceptable reliability criterion level on all clinician-administered interviews/scales. All participants reported hair-pulling and fulfilled at least criteria A, D, and E of DSM-IV/DSM-IVTR for TTM. Individuals diagnosed with mental retardation, autism spectrum disorders, or psychotic disorders were excluded.
3.1. Demographics The total sample consisted of 28 South African and 64 sex- and age-matched American hair-pullers. The demographic characteristics of participants are summarized in Table 1. Ninety-two (n = 92) participants completed the TIS questions addressing whether they experienced an increased physical tension or an “urge” immediately before pulling or when attempting to resist pulling (B) and whether they experienced a sense of pleasure/ gratification/relief after pulling (C). There were 86 (93.48%) individuals who reported increased physical tension or an “urge” immediately
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Table 1 Demographic characteristics of each group. Variables
Gender
Participants
Male Female
Mean age (S.D.) a
Statistic
Meeting criteria B and C for TTM at least “a little of the time”a (n = 82; 89.13%)
Not meeting criteria B and C for TTMa (n = 10; 10.87%)
p-value
5 77 (86.5%) 34.6 (12.6) years
0 10 35.2 (9.0) years
χ2 = 1.2, p = 0.3 t = 0.1, p = 0.9
From the TIS.
before pulling or when trying to resist pulling at least a little of the time. Six (6.52%) individuals reported that they never/almost never experienced these symptoms. Almost all of the participants (n = 87, 94.57%) indicated that they experienced a sense of pleasure/gratification/relief after pulling at least a little of the time. Four (4.35%) participants reported never/almost never experiencing these emotions after pulling. According to responses to the TIS, there were 82 (89.1%) participants who met both criteria B and C, and 10 (10.87%) who did not meet both these criteria. There was one (1.1%) participant who reported that she “did not know” whether or not he/she experienced a sense of pleasure/gratification/relief after pulling. Although the comparison groups were created based on the TIS, participants' responses to the TDI-R yielded similar data regarding endorsement of criteria B and C. Eighty-nine of the 92 that completed the TIS questions also completed this scale. There were 77 (86.52%) participants who met both criteria B and C of DSM-IV-TR TTM and 12 (13.48%) who did not meet both these criteria. 3.2. Clinical variables Not all participants that were interviewed completed all of the study scales. We include the numbers of participants who completed each of the MGH-HPS, DASS, and the SDS, respectively, in Table 2. Also see Table 2 for a comparison of those who did (n = 82) and those who did not (n = 10) meet Criteria B and C on these measures (according to the TIS) including outlier data points. 3.2.1. Hair-pulling severity MGH-HPS total scores ranged from 0 to 24 with a mean (S.D.) of 14.8 (4.37). Comparison of the two groups (both with and without the
one outlier) revealed no significant group difference in hair-pulling severity. 3.2.2. Depression, anxiety and stress In the total sample, depression scores on the DASS ranged from 0 to 36 and the mean score was 8.03 (S.D. = 9.0). The anxiety scores ranged from 0 to 24 and the mean was 4.17 (S.D. = 5.69). Stress scores on the DASS ranged from 0 to 38 with a mean score of 10.89 (S.D. = 9.46). The DASS anxiety subscale had two outliers. Analyses of DASS subscale scores both with and without the outliers revealed no significant differences between participants meeting both DSM-IV-TR TTM criteria B and C vs. those who did not satisfy both B and C. In a subsequent analysis, DASS anxiety subscale scores were transformed to correct for skewness; comparison analyses still failed to show group differences. 3.2.3. Other body-focused repetitive behaviors (BFRBs) Participants meeting DSM-IV-TR TTM criteria B and C (n = 68; mean = 0.81, S.D. = 0.87) did not differ significantly from those without B and C (n = 11; mean = 0.91, S.D. = 1.04) regarding the number of BFRBs that were endorsed (t = − 0.345, p = 0.731). 3.2.4. Functional impairment SDS disability scores for the entire sample ranged from 1 to 10 for work and social domains and from 1 to 8 for the home domain. Mean scores (S.D.) were 2.64 (1.93), 3.84 (2.26) and 2.41 (1.81) on the work, social and home domains, respectively. The SDS work subscale had one outlier. No significant group differences were reported on any of the SDS subscale scores for analyses with and without outliers when comparing those who did and did not meet criteria B and C.
Table 2 Comparison of TTM patients who did and did not meet DSM-IV-TR criteria B and C for TTM on several measures of clinical phenomenology. Variables
Participants
Statistics
Meeting criteria B and C for TTM “at least a little of the time”a Not meeting criteria B and C for TTMa MGH-HPS—total mean (S.D.)
n = 71: 15.08 (4.13) (no outliers)
DASS—depression mean (S.D.) n = 63: 8.31 (9.07) (no outliers) DASS—anxiety mean (S.D.) n = 63: 4.22 (5.74) (with outliers); n = 61: 3.57 (4.53) (without outliers) DASS—stress mean (S.D.) n = 63: 11.05 (9.62) (no outliers) SDS—work mean (S.D.) n = 69: 2.74 (1.97) (with outlier); n = 68: 2.63 (1.77) (without outlier) SDS—social mean (S.D.) n = 69: 3.91 (2.32) (no outliers) SDS—home mean (S.D.) n = 69: 2.48 (1.88) (no outliers) a
From the TIS.
n = 12: 13.08 (5.45) (with outlier); n = 11: 14.27 (3.74) (without outlier) n = 9: 6.0 (8.77) (no outliers) n = 9: 3.78 (5.70) (no outliers)
t = 1.5, p = 0.1 (with one outlier); t = 0.6, p = 0.5 (without outlier)
n = 9: 9.78 (8.74) (no outliers) n = 11: 2.0 (1.61) (no outliers)
t = 0.4; p = 0.7
n = 11: 3.36 (1.91) (no outliers) n = 11: 2.0 (1.34) (no outliers)
t = 0.7, p = 0.5
t = 0.7, p = 0.5 t = 0.2, p = 0.8 (with two outliers); t = − 0.1 p = 0.9 (without outliers)
t = 1.2, p = 0.2 (with outlier); t = 1.1, p = 0.3 (without outlier)
t = 0.8, p = 0.4
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Similar to the DASS analyses, we transformed the SDS work subscale to correct for the skewness; analyses with the corrected score also did not render significant differences between the two groups in terms of work impairment. 4. Discussion Examination of the DSM-IV-TR requirement of criteria B and C for a diagnosis of TTM in a large sample of hair-pullers who underwent structured clinical interviews indicated that most individuals reported increased physical tension or an “urge” immediately before pulling or when trying to resist pulling, and a sense of pleasure/gratification/ relief after pulling at least a little of the time. However, comparison of hair-pullers endorsing DSM-IV-TR TTM criteria B and C with those not endorsing both B and C revealed no significant group differences on any of the clinical variables assessed. The findings here suggest that in adult patients with current hairpulling, meeting criteria B and C does not appear to influence hairpulling severity, comorbid symptom severity, number of comorbid body-focused repetitive behaviors or impairment. The present study focused on one aspect of a previous investigation aimed at identifying key TTM subtypes (Lochner et al., 2010). However, the present study included patients from more sites, was done in a larger sample of individuals with hair-pulling, and implemented a different way of splitting the sample. Nevertheless, both studies reported similar findings — i.e. no significant group differences. The present findings are also similar to those found in the TIP-A study. In addition, keeping criteria B and C in the diagnostic set for hair-pulling disorder (TTM) may mean that 10% or more of affected cases may be “missed” or not diagnosed. Taken together, these data thus seem to suggest that criteria B and C for TTM should be omitted from DSM-5. However, there are some ideas for the replacement of criteria B and C in DSM-5 that merit consideration. In particular, criteria B and C convey the characteristic driven nature of pulling, i.e. that the person keeps pulling and is unable to stop, and so may be useful in a differential diagnosis. A monothetic criteria set, without criteria B and C, and focused only on hair-pulling per se, might create the impression of TTM as a single symptom, ignoring the fact that TTM is a syndrome with typical features. Further research to determine whether words such as “urge”, or alternative phrases such as “seemingly driven” are reliable and useful additions to the criteria set, is needed. Literature on other disorders of impulse-control, and addictive or body-focused stereotypic disorders with urge/tension and pleasure/relief/gratification “symptoms” similar to those seen in TTM, may also be useful in the search for suitable alternatives to the current diagnostic criteria. Future studies that include a comparison between patients with and without criterion B, and then between those meeting and those not meeting criterion C, may also contribute to the debate. There are a few limitations to this investigation that need consideration. The current study was done in a relatively small sample of patients. Future studies may benefit from inclusion of a larger sample, particularly in the group not meeting criteria B and C in particular. The unequal sample size of the comparison groups (more specifically, the small size of the one group) may have led to low statistical power and a subsequent lack of significant group differences. Instances where the pvalues were small but failed to denote significant group differences may thus have been the result of low statistical power. A type II error, or false negative, can thus not be ruled out here. Second, it is possible that meaningful differences between the groups would have emerged with different dependent variables. For example, variables not measured in this study such as family data, genetic data, or comprehensive treatment response data may have been predicted by those who did and did not meet criteria B and C for TTM. Although the samples from the USA and SA were age- and sex-matched, not analyzing other possible differences (e.g. in terms of psychiatric comorbidity) can be considered a limitation. While we compared patients from the combined sample with/out
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criteria B and C on their levels of depression, anxiety and stress, and on the number of comorbid body-focused repetitive behaviors, a more detailed comorbidity assessment and comparison of comorbid Axis Idisorders between the groups would have been useful to this investigation. Finally, the presence of outliers is another complicating factor that may have influenced statistical power. In summary, our findings do not provide convincing support for the inclusion of the current diagnostic criteria B and C for hair-pulling disorder (TTM) in DSM-5. Field trials to test the validity of proposed DSM-5 diagnostic criteria would be useful, as would the examination of other descriptors of hair-pulling urges and ‘failure to control’ symptoms. In addition, future research including monitoring of hair-pulling and associated symptoms moment by moment (i.e. exploring the specific phenomenological experiences occurring within each pulling episode) and longitudinally (i.e. exploring the typical phenomenological experiences occurring across hair-pulling episodes) may be useful to describe the nature of hair-pulling symptoms. Acknowledgments We would like to express our appreciation for the Trichotillomania Learning Center's assistance in data collection and financial support for this project.
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