DSM-5 field survey: Skin picking disorder
South African Medical Research Council, Research Unit on Anxiety and Stress Disorders, Department of Psychiatry, Stellenbosch University, Stellenbosch, South Africa
Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA
Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL, USA, Department of Public Health, University of Copenhagen, Copenhagen, DenmarkDan J. Stein, MD, PhD
South African Medical Research Council, Research Unit on Anxiety and Stress Disorders, Department of Psychiatry, Stellenbosch University, Stellenbosch, South Africa, Department of Psychiatry and Mental Health, University of Cape Town, Rondebosch, Cape Town, South Africa
BACKGROUND: Pathologic skin picking (skin picking disorder [SPD]) is a prevalent and disabling condition, which has received increasing study. It is timely to consider including SPD in DSM-5. The aim of this field survey was to investigate possible diagnostic criteria for SPD.
METHODS: Patients age >10 with skin-picking symptoms were recruited. Patients were assessed with 2 modules based on the Structured Clinical Interview for DSM, which addressed proposed DSM-5 diagnostic criteria for SPD. Additional questions were included to test other possible diagnostic criteria.
RESULTS: Thirty-eight patients had SPD. All had recurrent skin picking that resulted in skin lesions. Skin picking persisted despite repeated attempts to decrease or stop. “Urges” or “needs” to pull were not endorsed by all patients, but did correlate with severity of skin picking. “Resistance” to picking also was not universally endorsed.
CONCLUSIONS: These data support the proposed DSM-5 diagnostic criteria for SPD. Although most patients have urges to pick or a sense of relief when picking, such phenomena are not universal and should not be included in the diagnostic criteria set. An additional criterion of repeated attempts to decrease or stop skin picking seems warranted.
KEYWORDS: skin picking disorder, diagnostics, DSM-5
ANNALS OF CLINICAL PSYCHIATRY 2012;24(4):300-304
Pathologic skin picking, or skin picking disorder (SPD), is characterized by repetitive picking of skin, leading to tissue damage.1,2 This condition has been described in the literature, using various labels, such as, neurotic excoriation, compulsive picking, and dermatillomania. Recent data have pointed to the high prevalence3 and morbidity4 of SPD, and there has been growing interest in its underlying psychobiology5 and treatment.2
SPD would seem to meet criteria for a mental disorder,6 and the DSM-5 Work Group on Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorders has recommended its inclusion into DSM-5. Several proposed diagnostic criteria for this phenomenon have been presented;3,6-8 however, specific criteria have not been formally studied.
We developed a series of questions that addresses each of the proposed diagnostic criteria for SPD. Earlier proposals included diagnostic criteria focused on concepts of “urge” and “resistance,” mirroring the diagnostic criteria established for impulse-control disorder not otherwise specified (NOS).9 Based on arguments that in trichotillomania, or hair-pulling disorder (HPD), not all individuals demonstrate impulse-control disorder NOS symptoms, DSM-5 proposals for both HPD and SPD did not include these criteria. The following diagnostic criteria have, for example, been proposed for SPD6: A) recurrent skin picking resulting in skin lesions; B) the skin picking causes clinically significant distress or impairment in social, occupational, or other important areas of functioning; C) the skin picking is not due to the direct physiological effects of a substance (eg, cocaine) or a general medical condition (eg, scabies); and D) the skin picking is not restricted to the symptoms of another mental disorder (eg, skin picking due to fixed beliefs about skin infestation in delusional disorder, preoccupation with appearance in body dysmorphic disorder [BDD]). Nevertheless, we included questions to address related constructs such as “impulse,” “drive,” and “need” in an effort to ascertain their importance in SPD.
The study was reviewed and approved by the DSM-5 Work Group on Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorders. Two sites took part in the field survey: Stellenbosch University (Stellenbosch, South Africa) and the University of Minnesota Medical Center (Minneapolis, MN, USA). Both sites are involved in ongoing studies on SPD and HPD (trichotillomania), and are part of an established consortium for clinical collaboration.
Subjects were recruited from a cohort of patients presenting to the outpatient psychiatric clinics at each site for evaluation of SPD, and individuals from existing patient groups who continue to have skin picking symptoms. Patients were included if they were age >10, with primary pathological skin picking, or presented with prominent skin picking symptoms in the last 4 weeks.
All patients signed informed consent prior to questioning. Psychiatric comorbidity was allowed, but patients with a primary Axis I disorder other than SPD were excluded. Other exclusion criteria were current or past psychosis and inability to understand the study’s purpose and provide written informed consent.
All patients with skin picking symptoms were interviewed using questions based on the proposed DSM-5 criteria for SPD. Additional questions were based on other proposals, as well as to test other possible criteria addressing recurrent urges, needs, drives, or impulses to pick, repeated attempts to resist skin picking, and persistence of skin picking despite attempts to decrease or stop. The 3 clinicians taking part in the field survey reported on the acceptability of each criterion, using selected items of the DSM-5’s Clinical Utility Questionnaire.
Measures to assess skin picking severity in the last 4 weeks or month were the Florida Obsessive-Compulsive Inventory (FOCI; adapted for SPD)10 and the Skin Picking Scale (SPS).11 The Milwaukee Inventory for the Dimensions of Adult Skin Picking was administered to assess aspects of skin picking in the last 4 weeks or month.12
We determined the frequency with which different criteria were endorsed in our sample of patients with skin picking symptoms. In addition, we studied the association between these criteria and scores on the skin picking symptom severity scales.
We obtained written, informed consent from all patients. The study procedures were explained in lay terminology to all patients. The patients were informed that all data are kept strictly confidential and the results of the study will be made public and published without compromising confidentiality. All data were delinked from patient-identifying information. Patients were informed that they are free to withhold or to withdraw participation in this trial without compromising future care. There was no cost to participate in the study. The institutional review boards of the 2 participating sites approved the study protocol and consent procedures.
Forty (35 female; 87.5%) patients with skin picking symptoms were included in the field survey. The sample consisted of 19 South African (16 female; 84.2%) and 21 American (19 female; 90.5%) patients. All patients were white. Mean age at the time of the interview was 36.7±12.3 (range 18 to 67).
Mean age of skin picking onset and skin picking severity scores are depicted in the TABLE.
Age of onset of skin picking symptoms and severity scores (N = 40)
|Age of onset of skin pickinga
|FOCI total score
|SPS total score
Proposed DSM-5 diagnostic criteria
All 40 patients reported recurrent skin picking resulting in skin lesions that were not due to the direct physiological effects of substance use or a general medical condition. A comprehensive clinical interview established that skin picking was not restricted to the symptoms of another mental disorder, such as BDD. Thirty-eight (95%) patients had skin picking that caused clinically significant distress or impairment in social, occupational, or other important areas of functioning.
The clinical utility of the proposed DSM-5 diagnostic criteria ranged from slightly useful to extremely useful. Clinicians found these criteria very useful or extremely useful (n = 33; 82.5%) or very easy or extremely easy (n = 33; 82.5%) to apply when deciding whether SPD was present.
Proposed additional diagnostic criteria
Most patients (n = 37; 92.5%) reported recurrent urges to pick skin. Slightly more than one-half of the sample (n = 21; 52.5%) reported skin picking was in response to recurrent “needs” to pick. Three items evaluated “drives” to pick: 20 (50%) patients reported “recurrent drives to pick,” 18 (45%) reported their picking “is seemingly driven,” and 21 (52.5%) patients reported their skin picking is “…in response to drives to pick….”
Thirty-nine (97.5%) patients reported repeated attempts to resist skin picking. The 1 patient who did not report resisting skin picking qualified for a DSM-5 diagnosis of SPD, but had relatively low symptom severity. All patients had skin picking that persisted despite repeated attempts to decrease or stop. In most cases (n = 39; 97.5%), the clinician determined that skin picking was not due to the direct physiological effects of a substance.
Clinicians were asked which of the proposed “additional” diagnostic criteria were most useful in its application to the 40 skin picking cases included in this survey. In sequence, from the most helpful criterion, clinicians reported that in 17 cases (42.5%) the fact that skin picking persisted despite attempts to decrease or stop was the most useful diagnostic criterion. In 13 cases (32.5%), recurrent urges to pick or engage in skin picking in response to an urge was seen as the most useful criterion. Resistance to skin picking was noted as the most useful diagnostic criterion for 6 patients (15%).
In the majority of cases (n = 31; 77.5%), the clinicians found the additional criteria very to extremely useful, helpful, or easy (n = 24; 60%) to apply in their decision about whether SPD was present. For 31 (77.5%) patients, clinicians found the proposed diagnostic criteria to fit (moderately to extremely) with the presentations they have seen in other patients with problematic skin picking.
Based on the proposed DSM-5 criteria, there were only 2 patients who did not report functional impairment due to skin picking. The severity of the skin picking in these 2 cases was significantly less than the rest of the sample (SPS total score: t = -2.6; P = .012; FOCI total score: t = -2.6; P = .013). Analyses of the data excluding these 2 cases did not alter other reported findings.
Patients who reported recurrent urges to pick or skin picking in response to these urges had more severe skin picking than those without (SPS and FOCI: P < .05). Similarly, participants who reported that their skin picking was “seemingly driven” had significantly more severe skin picking than those without (SPS and FOCI: P < .05).
This field trial’s main finding was that the data endorse the proposed DSM-5 diagnostic criteria. All participants had recurrent skin picking resulting in a skin lesion that was not due to the direct physiological effects of a substance or a general medical condition and was not restricted to the symptoms of another mental disorder. Skin picking severity varies among the population, and those who did not meet the clinical significance criterion had significantly less severe skin picking symptoms.
In addition, skin picking among all participants was noted to persist despite repeated attempts to decrease or stop. Such resistance to skin picking seems to be a key feature of SPD, and a diagnostic criterion addressing this should be added. However, a criterion that incorporates the term “resist” is not universally endorsed, and clinicians did not find this criterion particularly useful in making the diagnosis. The simpler construct of “attempts to decrease or stop skin picking” should be used.
Diagnostic criteria focused on “need,” “drive,” or “impulse” are endorsed by one-half of participants and should not be included in the diagnostic criteria set. It is notable that participants who do endorse these criteria may have more severe skin picking symptoms. Therefore these features of SPD should be described in the accompanying text.
We propose that the diagnostic criteria for SPD in DSM-5 include A) a criterion referring to recurrent skin picking resulting in skin lesions, B) a criterion referring to repeated attempts to decrease or stop skin picking, C) a substance and medical disorder exclusion criterion, D) a mental disorder diagnostic hierarchy criterion, and E) a clinical significance criterion.
These diagnostic criteria for SPD mirror those of HPD (trichotillomania) and are consistent with previous work documenting similarities in the symptomatology of clinically significant hair pulling and skin picking.12,13
Limitations of this field study include the relatively small sample size. SPD appears to be a relatively homogenous condition, and a larger sample is unlikely to reveal significantly different findings. Also, it could be argued that the sample is not representative of SPD patients because the 2 trial sites are specialist research sites. Nevertheless, the sample included participants with skin picking that ranged in severity from mild to severe. The majority of the sample was female and all participants were age ≥18; further work is needed to assess these diagnostic criteria in children and adolescents. It is noteworthy that English was not the first language of many participants from South Africa; critical words such as “urge,” “need,” “drive,” and “impulse” do not have precise equivalents in local languages, although we suspect that the proposed diagnostic criteria are more easily translated, work in additional languages is needed to confirm this.
The DSM-5 Work Group on Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorders has argued that based on accumulating evidence on prevalence, morbidity, psychobiology, and treatment response, it is timely to include SPD in DSM-5.6 The current data support the proposed DSM-5 criteria, and suggest 1 additional criterion. Inclusion of this condition as a discrete disorder in DSM-5 would create greater awareness of this condition and arguably allow and encourage further studies of its phenomenology, psychobiology, and treatment, as occurred with HPD.6 The data here indicate that the proposed criteria can be implemented in a typical clinical interview and operationalized or assessed for research purposes; clinicians noted that the proposed diagnostic criteria were moderately to extremely useful or easy to apply.
In summary, this was a dual-site field survey designed to examine proposed diagnostic criteria in patients with SPD. We believe that the criteria proposed here are evidence-based and clinically useful. Additional work to assess interrater reliability and test-retest reliability of the proposed criteria, as well as to assess their applicability to children and adolescents with SPD, may be valuable.
DISCLOSURES: Dr. Lochner reports no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products. Dr. Grant receives grant or research support from Forest Pharmaceuticals, the National Center for Responsible Gaming, and the National Institute on Drug Abuse. Mr. Odlaug has received grant or research support from the Trichotillomania Learning Center and has received honoraria from Oxford University Press. Dr. Stein has received research grants and/or consultancy honoraria from Abbott, AstraZeneca, Eli Lilly and Company, GlaxoSmithKline, Jazz Pharmaceuticals, Johnson & Johnson, Lundbeck, Orion, Pfizer, Pharmacia, Roche, Servier, Solvay, Sumitomo, Takeda, Tikvah, and Wyeth.
ACKNOWLEDGEMENTS: This article was generated as part of the DSM-5 Work Group activities, ©2012 by the American Psychiatric Association.
The authors thank the Trichotillomania Learning Center (Santa Cruz, CA, USA) for support for clinical collaboration. We also wish to thank the DSM-5 Anxiety, Obsessive-Compulsive Spectrum, Posttraumatic, and Dissociative Disorders Work Group and its chair, Dr. Katharine Phillips, for their helpful inputs.
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