Evidence for reduced cerebellar volumes in trichotillomania

Exploring pharmacological treatment for trichotillomania: do we need better education?

BACKGROUND

Trichotillomania, also known as hair-pulling disorder, is a chronic psychiatric condition with a fluctuating course in which an individual pulls out their hair, leading to visible hair loss and psychosocial sequelae. Due to the unknown pathogenesis, the treatment of this disorder is complex and remains a challenge for dermatologists and psychiatrists. Since guidelines for treating trichotillomania are lacking and, consequently, no common treatment strategy exists, we decided to perform a large-scale, global retrospective cohort study to assess the characterized real-world prescription patterns in treating trichotillomania.

METHODS

The research used the TrinetX database for patients with trichotillomania (ICD 10 - F63.3) within the European and the United States Collaborative Network (EC and UC, respectively). After consulting with a psychodermatology expert, a list of 25 medications was investigated.

RESULTS

Data on the prescription drugs of 1,275 patients from the EC and 109,741 patients from the UC were collected. In both the EC and UC cohorts, benzodiazepine derivatives, particularly lorazepam and midazolam, were the most commonly prescribed sedatives/hypnotics. Antipsychotic prescriptions, primarily haloperidol, followed benzodiazepines. After the trichotillomania diagnosis, notable changes in drug prescriptions for the EC cohort, including an increased likelihood of receiving acetylcysteine, haloperidol, quetiapine, sertraline, olanzapine, and risperidone were observed. The UC cohort showed minimal changes. Overall, both cohorts leaned toward benzodiazepine prescriptions (37% UC, 21% EC) and had limited antidepressant usage. Haloperidol (19.3%) and quetiapine (15.1%) were commonly prescribed in both cohorts.

CONCLUSIONS

The results of our study indicate that the real-world prescription patterns for trichotillomania differ significantly from the expert-proposed therapeutic approach and point toward the necessity of creating standards of pharmacological care and better education.

MRI morphometry of the anterior and posterior cerebellar vermis and its relationship to sensorimotor and cognitive functions in children

INTRODUCTION

The human cerebellum emerges as a posterior brain structure integrating neural networks for sensorimotor, cognitive, and emotional processing across the lifespan. Developmental studies of the cerebellar anatomy and function are scant. We examine age-dependent MRI morphometry of the anterior cerebellar vermis, lobules I-V and posterior neocortical lobules VI-VII and their relationship to sensorimotor and cognitive functions.

METHODS

Typically developing children (TDC; n=38; age 9-15) and healthy adults (HAC; n=31; 18-40) participated in high-resolution MRI. Rigorous anatomically informed morphometry of the vermis lobules I-V and VI-VII and total brain volume (TBV) employed manual segmentation computer-assisted FreeSurfer Image Analysis Program [http://surfer.nmr.mgh.harvard.edu]. The neuropsychological scores (WASI-II) were normalized and related to volumes of anterior, posterior vermis, and TBV.

RESULTS

TBVs were age independent. Volumes of I-V and VI-VII were significantly reduced in TDC. The ratio of VI-VII to I-V (∼60%) was stable across age-groups; I-V correlated with visual-spatial-motor skills; VI-VII with verbal, visual-abstract and FSIQ.

CONCLUSIONS

In TDC neither anterior I-V nor posterior VI-VII vermis attained adult volumes. The "inverted U" developmental trajectory of gray matter peaking in adolescence does not explain this finding. The hypothesis of protracted development of oligodendrocyte/myelination is suggested as a contributor to TDC's lower cerebellar vermis volumes.

Comparing the 'When' and the 'Where' of Electrocortical Activity in Patients with Tourette Syndrome, Body-Focused Repetitive Behaviors, and Obsessive Compulsive Disorder

Background/Objectives: Tourette Syndrome (TS), Obsessive Compulsive Disorder (OCD), and Body-Focused Repetitive Behaviors (BFRB) are three disorders that share many similarities in terms of phenomenology, neuroanatomy, and functionality. However, despite the literature pointing toward a plausible spectrum of these disorders, only a few studies have compared them. Studying the neurocognitive processes using Event-Related Potentials (ERPs) offers the advantage of assessing brain activity with excellent temporal resolution. The ERP components can then reflect specific processes known to be potentially affected by these disorders. Our first goal is to characterize 'when' in the processing stream group differences are the most prominent. The second goal is to identify 'where' in the brain the group discrepancies could be. Methods: Participants with TS (n = 24), OCD (n = 18), and BFRB (n = 16) were matched to a control group (n = 59) and were recorded with 58 EEG electrodes during a visual counting oddball task. Three ERP components were extracted (i.e., P200, N200, and P300), and generating sources were modelized with Standardized Low-Resolution Electromagnetic Tomography. Results: We showed no group differences for the P200 and N200 when controlling for anxiety and depressive symptoms, suggesting that the early cognitive processes reflected by these components are relatively intact in these populations. Our results also showed a decrease in the later anterior P300 oddball effect for the TS and OCD groups, whereas an intact oddball effect was observed for the BFRB group. Source localization analyses with sLORETA revealed activations in the lingual and middle occipital gyrus for the OCD group, distinguishing it from the other two clinical groups and the controls. Conclusions: It seems that both TS and OCD groups share deficits in anterior P300 activation but reflect distinct brain-generating source activations.

Impulsivity in adolescent girls diagnosed with trichotillomania: an evaluation of clinical and neuropsychological characteristics

The aim of this study is to compare the clinical and neuropsychological features of impulsivity in adolescent girls with trichotillomania (TTM) and healthy controls, and to assess the relationships between the severity of TTM and the impulsivity/concomitant symptoms of anxiety and depression. The study sample consisted of 43 adolescent girls who were 12 to 18 years old. The Kiddie-Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version DSM-5 (K-SADS-PL) was administered to the adolescents and their parents. All of the participants completed a sociodemographic data form, the Revised Children's Anxiety and Depression Scale-Child Version (RCADS-CV), the Barratt Impulsiveness Scale-Brief (BIS-Brief), and the Massachusetts General Hospital Hairpulling Scale (MGH-HPS). The Eriksen Flanker task, the Stop Signal Reaction Time (SSRT) task, the Go/No-Go task, and the Balloon Analog Risk Task (BART) were used to assess behavioral impulsivity. The adolescents with TTM reported higher levels of impulsivity and anxiety/depression symptoms than the healthy controls, and they also performed worse on the behavioral tasks. While there were no relationships between clinical and behavioral impulsivity and TTM severity, social anxiety symptoms were the most important predictor of the severity of TTM. It seems important to better understand the role of impulsivity in the onset and persistence of TTM symptoms in adolescents.

Three-Dimensional Digital Reconstruction of the Cerebellar Cortex: Lobule Thickness, Surface Area Measurements, and Layer Architecture

The cerebellum is ontogenetically one of the first structures to develop in the central nervous system; nevertheless, it has been only recently reconsidered for its significant neurobiological, functional, and clinical relevance in humans. Thus, it has been a relatively under-studied compared to the cerebrum. Currently, non-invasive imaging modalities can barely reach the necessary resolution to unfold its entire, convoluted surface, while only histological analyses can reveal local information at the micrometer scale. Herein, we used the BigBrain dataset to generate area and point-wise thickness measurements for all layers of the cerebellar cortex and for each lobule in particular. We found that the overall surface area of the cerebellar granular layer (including Purkinje cells) was 1,732 cm2 and the molecular layer was 1,945 cm2. The average thickness of the granular layer is 0.88 mm (± 0.83) and that of the molecular layer is 0.32 mm (± 0.08). The cerebellum (both granular and molecular layers) is thicker at the depth of the sulci and thinner at the crowns of the gyri. Globally, the granular layer is thicker in the lateral-posterior-inferior region than the medial-superior regions. The characterization of individual layers in the cerebellum achieved herein represents a stepping-stone for investigations interrelating structural and functional connectivity with cerebellar architectonics using neuroimaging, which is a matter of considerable relevance in basic and clinical neuroscience. Furthermore, these data provide templates for the construction of cerebellar topographic maps and the precise localization of structural and functional alterations in diseases affecting the cerebellum.

Neurobiology of subtypes of trichotillomania and skin picking disorder

BACKGROUND

Trichotillomania (TTM) and skin picking disorder (SPD) are common and often debilitating mental health conditions, grouped under the umbrella term of body-focused repetitive behaviors (BFRBs). Recent clinical subtyping found that there were three distinct subtypes of TTM and two of SPD. Whether these clinical subtypes map on to any unique neurobiological underpinnings, however, remains unknown.

METHODS

Two hundred and fifty one adults [193 with a BFRB (85.5% [n = 165] female) and 58 healthy controls (77.6% [n = 45] female)] were recruited from the community for a multicenter between-group comparison using structural neuroimaging. Differences in whole brain structure were compared across the subtypes of BFRBs, controlling for age, sex, scanning site, and intracranial volume.

RESULTS

When the subtypes of TTM were compared, low awareness hair pullers demonstrated increased cortical volume in the lateral occipital lobe relative to controls and sensory sensitive pullers. In addition, impulsive/perfectionist hair pullers showed relative decreased volume near the lingual gyrus of the inferior occipital-parietal lobe compared with controls.

CONCLUSIONS

These data indicate that the anatomical substrates of particular forms of BFRBs are dissociable, which may have implications for understanding clinical presentations and treatment response.

Acceptance-enhanced behavior therapy for trichotillomania in adults: A randomized clinical trial

Given the limited treatment options for trichotillomania (TTM), or Hair Pulling Disorder, this large randomized clinical trial evaluated the efficacy of acceptance-enhanced behavior therapy for TTM (AEBT-TTM) in reducing TTM severity relative to psychoeducation and supportive therapy (PST). Eighty-five adults (78 women) with TTM received 10 sessions (over 12 weeks) of either AEBT-TTM or PST. Independent evaluators masked to treatment assignment assessed participants at baseline (week 0), midpoint (week 6), and endpoint (week 12). Consistent with a priori hypotheses, 64% of the adults treated with AEBT-TTM were classified as clinical responders at post-treatment relative to 38% treated with PST. Clinical responders were identified by a score of 1 or 2 on the Clinical Global Impressions-Improvement (CGI-I) scale. Relative to the PST group, the AEBT-TTM group demonstrated significantly greater pre-to post-treatment reductions on the self-report Massachusetts General Hospital-Hairpulling Scale (MGH-HS) and the evaluator-rated National Institute of Mental Health Trichotillomania Severity Scale (NIMH-TSS). There were no significant post-treatment group differences on the Clinical Global Impressions-Severity (CGI-S) scale, or rate of TTM diagnoses. Results suggest AEBT-TTM provides greater treatment benefit than PST. Future research should continue to investigate AEBT-TTM along with mediators and moderators of its efficacy.

Anatomically curated segmentation of human subcortical structures in high resolution magnetic resonance imaging: An open science approach

Magnetic resonance imaging (MRI)-based brain segmentation has recently been revolutionized by deep learning methods. These methods use large numbers of annotated segmentations to train algorithms that have the potential to perform brain segmentations reliably and quickly. However, training data for these algorithms are frequently obtained from automated brain segmentation systems, which may contain inaccurate neuroanatomy. Thus, the neuroimaging community would benefit from an open source database of high quality, neuroanatomically curated and manually edited MRI brain images, as well as the publicly available tools and detailed procedures for generating these curated data. Manual segmentation approaches are regarded as the gold standard for brain segmentation and parcellation. These approaches underpin the construction of neuroanatomically accurate human brain atlases. In addition, neuroanatomically precise definitions of MRI-based regions of interest (ROIs) derived from manual brain segmentation are essential for accuracy in structural connectivity studies and in surgical planning for procedures such as deep brain stimulation. However, manual segmentation procedures are time and labor intensive, and not practical in studies utilizing very large datasets, large cohorts, or multimodal imaging. Automated segmentation methods were developed to overcome these issues, and provide high data throughput, increased reliability, and multimodal imaging capability. These methods utilize manually labeled brain atlases to automatically parcellate the brain into different ROIs, but do not have the anatomical accuracy of skilled manual segmentation approaches. In the present study, we developed a custom software module for manual editing of brain structures in the freely available 3D Slicer software platform that employs principles and tools based on pioneering work from the Center for Morphometric Analysis (CMA) at Massachusetts General Hospital. We used these novel 3D Slicer segmentation tools and techniques in conjunction with well-established neuroanatomical definitions of subcortical brain structures to manually segment 50 high resolution T1w MRI brains from the Human Connectome Project (HCP) Young Adult database. The structural definitions used herein are associated with specific neuroanatomical ontologies to systematically interrelate histological and MRI-based morphometric definitions. The resulting brain datasets are publicly available and will provide the basis for a larger database of anatomically curated brains as an open science resource.

Trichotillomania and Skin-Picking Disorder: An Update

Trichotillomania (hair pulling disorder) and skin-picking (excoriation) disorder are common neuropsychiatric disorders (each with a point prevalence of around 2%) but are underrecognized by professionals. Affected individuals repeatedly pull out their own hair or pick at their skin, and these symptoms not only have a negative impact on these individuals because of the time they occupy but can also lead to considerable physical disfigurement, with concomitant loss of self-esteem and avoidance of social activities and intimate relationships. The behaviors may also have serious physical consequences. Trichotillomania and skin picking frequently co-occur, and both disorders commonly present with co-occurring depression, anxiety, impulsive, and obsessive-compulsive disorders. Behavioral therapy currently appears to be the most effective treatment for both. Pharmacotherapy, in the form of N-acetylcysteine or olanzapine, may also play a role in treatment.

Reward processing in trichotillomania and skin picking disorder

Trichotillomania (hair pulling disorder) and skin picking disorder are common and often debilitating mental health conditions, grouped under the umbrella term of body focused repetitive behaviors (BFRBs). Although the pathophysiology of BFRBs is incompletely understood, reward processing dysfunction has been implicated in the etiology and sustention of these disorders. The purpose of this study was to probe reward processing in BFRBs. 159 adults (125 with a BFRB [83.2% (n = 104) female] and 34 healthy controls [73.5% (n = 25) female]) were recruited from the community for a multi-center between-group comparison using a functional imaging (fMRI) monetary reward task. Differences in brain activation during reward anticipation and punishment anticipation were compared between BFRB patients and controls, with stringent correction for multiple comparisons. All group level analyses controlled for age, sex and scanning site. Compared to controls, BFRB participants showed marked hyperactivation of the bilateral inferior frontal gyrus (pars opercularis and pars triangularis) compared to controls. In addition, BFRB participants exhibited increased activation in multiple areas during the anticipation of loss (right fusiform gyrus, parahippocampal gyrus, cerebellum, right inferior parietal lobule; left inferior frontal gyrus). There were no significant differences in the win-lose contrast between the two groups. These data indicate the existence of dysregulated reward circuitry in BFRBs. The identified pathophysiology of reward dysfunction may be useful to tailor future treatments.

Hair-pulling disorder (Trichotillomania): Etiopathogenesis, diagnosis and treatment in a nutshell

Hair-pulling disorder (Trichotillomania) is a disabling mental disorder. Patient's behavior is characterized by the recurrent pulling of own hair with hair loss and a marked dysfunction in various areas of daily life. Trichotillomania is a relatively common disorder with pediatric onset, often associated with significant morbidity, comorbidity, and functional decline. Surprisingly, children or adolescents have been little studied in the research studies on the pathophysiology and psychopathology of trichotillomania. Furthermore, more evidences regarding the effective and evidence-based pharmacological interventions for the treatment of this condition are encouraged. This narrative review will report on the etiopathogenesis and clinical manifestations of trichotillomania including criteria for diagnosis and treatment issues of this complex mental disorder.

Drug Treatment of Trichotillomania (Hair-Pulling Disorder), Excoriation (Skin-picking) Disorder, and Nail-biting (Onychophagia)

BACKGROUND

Trichotillomania (TTM), excoriation (or skin-picking) disorder and some severe forms of onychophagia are classified under obsessive-compulsive and related disorders. There are different interacting neurotransmitter systems involved in the pathophysiology of impulse-control disorders, implicating noradrenaline, serotonin, dopamine, opioid peptides and glutamate, hence investigators focused on drugs able to act on these transmitters. Our aim was to critically review the efficacy of the drugs employed in impulse-control disorders.

METHODS

We searched for controlled drug trials to treat TTM, excoriation, and/or nail-biting six databases (PubMed, Cochrane, Scopus, CINAHL, PsycINFO/PsycARTICLES, and Web of Science), using the search strategy: (trichotillomania OR "excoriation disorder" OR "face picking" OR "skin picking" OR "hair pulling" OR onychophagia OR "nail-biting") AND drug treatment on 12 March 2018 for all databases. We followed in our method of identifying relevant literature the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

RESULTS

SSRIs and clomipramine are considered first-line in TTM. In addition, family members of TTM patients are often affected by obsessive-compulsive spectrum disorders. Other drugs used in the treatment of TTM are lamotrigine, olanzapine, N-Acetylcysteine, inositol, and naltrexone.

CONCLUSION

The treatment of TTM, excoriation disorder and nail-biting is still rather disappointing. Conjectures made from preclinical studies and the relative pathophysiological hypotheses found poor confirmations at a clinical level. There is a need for further studies and the integration of pharmacological and psychotherapeutic. Our results point to the need of integrating personalised medicine principles in the treatment of these patients.

Trichotillomania is more related to Tourette disorder than to obsessive-compulsive disorder

OBJECTIVE

Trichotillomania (TTM) is characterized by the pulling out of one's hair. TTM was classified as an impulse control disorder in DSM-IV, but is now classified in the obsessive-compulsive related disorders section of DSM-5. Classification for TTM remains an open question, especially considering its impact on treatment of the disorder. In this review, we questioned the relation of TTM to tic disorder and obsessive-compulsive disorder (OCD).

METHOD

We reviewed relevant MEDLINE-indexed articles on clinical, neuropsychological, neurobiological, and therapeutic aspects of trichotillomania, OCD, and tic disorders.

RESULTS

Our review found a closer relationship between TTM and tic disorder from neurobiological (especially imaging) and therapeutic standpoints.

CONCLUSION

We sought to challenge the DSM-5 classification of TTM and to compare TTM with both OCD and tic disorder. Some discrepancies between TTM and tic disorders notwithstanding, several arguments are in favor of a closer relationship between these two disorders than between TTM and OCD, especially when considering implications for therapy. This consideration is essential for patients.

White matter volume alterations in hair-pulling disorder (trichotillomania)

Trichotillomania (TTM) is a disorder characterized by repetitive hair-pulling resulting in hair loss. Key processes affected in TTM comprise affective, cognitive, and motor functions. Emerging evidence suggests that brain matter aberrations in fronto-striatal and fronto-limbic brain networks and the cerebellum may characterize the pathophysiology of TTM. The aim of the present voxel-based morphometry (VBM) study was to evaluate whole brain grey and white matter volume alteration in TTM and its correlation with hair-pulling severity. High-resolution magnetic resonance imaging (3 T) data were acquired from 29 TTM patients and 28 age-matched healthy controls (CTRLs). All TTM participants completed the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) to assess illness/pulling severity. Using whole-brain VBM, between-group differences in regional brain volumes were measured. Additionally, within the TTM group, the relationship between MGH-HPS scores, illness duration and brain volumes were examined. All data were corrected for multiple comparisons using family-wise error (FWE) correction at p < 0.05. Patients with TTM showed larger white matter volumes in the parahippocampal gyrus and cerebellum compared to CTRLs. Estimated white matter volumes showed no significant association with illness duration or MGH-HPS total scores. No significant between-group differences were found for grey matter volumes. Our observations suggest regional alterations in cortico-limbic and cerebellar white matter in patients with TTM, which may underlie deficits in cognitive and affective processing. Such volumetric white matter changes may precipitate impaired cortico-cerebellar communication leading to a reduced ability to control hair pulling behavior.

The Role of the Cerebellum in Skin-Picking Disorder

Previous research indicated that the cerebellum is involved in psychopathologies with body-focused repetitive behaviors. The present study investigated whether patients with a diagnosis of skin-picking disorder (SPD) also show altered cerebellar structure and function. Structural as well as functional MRI data from 30 SPD patients and 31 controls were analyzed. The fMRI approach compared cerebellar activity and connectivity between the two groups during scratching and caressing of a small skin area on the arm. Relative to controls, SPD patients were characterized by reduced gray matter volumes in the left cerebellar lobules V and VI. During picking (relative to caressing), SPD patients displayed increased activation of the left crus I, which showed enhanced coupling with the left ventrolateral prefrontal cortex (VLPFC). This study provides the first evidence that SPD patients display structural as well as functional abnormalities in specific subregions of the cerebellum related to motor (V) and affective-cognitive functions (VI, crus I). The SPD-related altered cerebellar connectivity with an area implicated in affect control (VLPFC) fits nicely to the model of pathological skin picking as a maladaptive emotion regulation strategy.

The relationship between microstructural alterations of the brain and clinical measurements in children and adolescents with hair pulling disorder

Several studies have evaluated gray matter abnormalities and white matter integrity in adults with hair pulling disorder (HPD). However, no prior studies have defined the relationship between neuroimaging parameters and clinical measurements in children and adolescents with HPD. The purposes of this study were to determine the correlation between magnetic resonance imaging (MRI) indices and clinical measurements in children and adolescents with HPD, and to compare HPD patients with age- and sex- matched healthy controls (HC). Pediatric HPD patients (n = 9) and HC subjects (n = 10), aged 9-17 years, were recruited. Three-dimensional T1-weighted structural MRI (3D T1W) and diffusion-tensor imaging (DTI) scans were obtained for each subject. Gray matter and white matter volumes were calculated from 3D T1W. Fractional anisotropy (FA) and average diffusion coefficients (D_av) were mapped from DTI. Voxel-based and region-of-interest correlations between MRI indices and clinical measurements were analyzed. In addition, two-sample t-tests were used to compare voxel-based tissue volumes, FA, and D_av maps between the two groups. Alterations in both brain tissue volume and white matter integrity were associated with symptom severity, especially in the precuneus, anterior cingulate, temporal cortex, and frontal cortex regions. FA values in HPD patients were significantly higher than those observed in HC subjects, particularly in the cerebellum and cuneus regions. Alterations of brain tissue volumes and microstructural changes are associated with severity of clinical symptoms in children and adolescents with HPD. Fractional anisotropy is the most sensitive method to distinguish pediatric HPD patients from healthy children. The results of this study can facilitate use of MRI indices to follow the transition from pediatric HPD to adult HPD.

Cortical thickness abnormalities in trichotillomania: international multi-site analysis

Trichotillomania is a prevalent but often hidden psychiatric condition, characterized by repetitive hair pulling. The aim of this study was to confirm or refute structural brain abnormalities in trichotillomania by pooling all available global data. De-identified MRI scans were pooled by contacting authors of previous studies. Cortical thickness and sub-cortical volumes were compared between patients and controls. Patients (n = 76) and controls (n = 41) were well-matched in terms of demographic characteristics. Trichotillomania patients showed excess cortical thickness in a cluster maximal at right inferior frontal gyrus, unrelated to symptom severity. No significant sub-cortical volume differences were detected in the regions of interest. Morphometric changes in the right inferior frontal gyrus appear to play a central role in the pathophysiology of trichotillomania, and to be trait in nature. The findings are distinct from other impulsive-compulsive disorders (OCD, ADHD, gambling disorder), which have typically been associated with reduced, rather than increased, cortical thickness. Future work should examine sub-cortical and cerebellar morphology using analytic approaches designed for this purpose, and should also characterize grey matter densities/volumes.

Computerized response inhibition training for children with trichotillomania

Evidence suggests that trichotillomania is characterized by impairment in response inhibition, which is the ability to suppress pre-potent/dominant but inappropriate responses. This study sought to test the feasibility of computerized response inhibition training for children with trichotillomania. Twenty-two children were randomized to the 8-session response inhibition training (RIT; n = 12) or a waitlisted control (WLT; n = 10). Primary outcomes were assessed by an independent evaluator, using the Clinical Global Impression-Improvement (CGI-I), and the NIMH Trichotillomania Severity (NIMH-TSS) and Impairment scales (NIMH-TIS) at pre, post-training/waiting, and 1-month follow-up. Relative to the WLT group, the RIT group showed a higher response rate (55% vs. 11%) on the CGI-I and a lower level of impairment on the NIMH-TIS, at post-training. Overall symptom reductions rates on the NIMH-TSS were 34% (RIT) vs. 21% (WLT) at post-training. The RIT's therapeutic gains were maintained at 1-month follow-up, as indicated by the CGI-I responder status (= 66%), and a continuing reduction in symptom on the NIMH-TSS. This pattern of findings was also replicated by the 6 waitlisted children who received the same RIT intervention after post-waiting assessment. Results suggest that computerized RIT may be a potentially useful intervention for trichotillomania.

Systematic Review of Published Primary Studies of Neuropsychology and Neuroimaging in Trichotillomania

OBJECTIVES

Existing models of trichotillomania (TTM; hair pulling disorder) rely heavily on a biological predisposition or biological pathogenesis of the disorder, but fail to capture the specific neuropsychological mechanisms involved. The present systematic review aims to scope existing neuropsychological studies of TTM to explore gaps in current models.

METHODS

A systematic literature search was conducted to detect all published primary studies using neuropsychological and neuroimaging measures in a cohort of individuals experiencing TTM. Studies addressing neuropsychological function were divided into domains. Findings from imaging studies were considered within brain regions and across methodology.

RESULTS

Thirty studies with a combined 591 participants with TTM, 372 healthy controls and 225 participants in other types of control group were included. Sixteen studies investigated neuropsychological parameters, and 14 studies pursued neuroimaging technologies. Available studies that used neuropsychological assessments and reported a statistically significant difference between those with TTM and controls ranged in effect size from 0.25 to 1.58. All domains except verbal ability and visual ability reported a deficit. In neuroimaging studies, several structural and functional brain changes were reported that might be of significance to TTM. Only tentative conclusions can be made due to the use of multiple methodologies across studies, a major limitation to meaningful interpretations.

CONCLUSIONS

Positive neuropsychological and neuroimaging results require replication, preferably with multi-site studies using standardized methodology. Increased standardized testing and analyses across the literature, as a whole, would improve the utility and interpretability of knowledge in this field. (JINS, 2018, 24, 188-205).

“Pulling hair out of the head” - the importance of traumatic family events in the development and maintenance of trichotillomania symptoms - case report

Introduction: Trichotillomania is a mental disorder characterized by a repetitive and compulsive hair pulling, classified in ICD-10 to a group of habit and impulse disorders, and in the DSM-5 to the group of obsessive-compulsive disorders.

Aim: The aim of the study is to present on the basis of case study:1). the importance of traumatic family experiences in releasing as well as maintaining the symptoms of Trichotillomania, 2). comprehensive medical care, the application of which has resulted in a beneficial therapeutic effect.

Results: In the described case of 16-year-old patient, Trichotillomania was triggered by traumatic events related to lack of support and family stabilization resulting from parental disputes and grandfather’s death, when she was 11 years old. The subsequent years of her life, in spite of the divorce of her parents and their separate residence, abounded in periods of turbulent quarrels between the parents in which she was involved. Each time this type of incident was associated with the recurrence of behavior associated with Trichotil-lomania, the course of which was more severe with the occurrence of self-harm and suicidal thoughts.

Conclusions: 1. In the described case, traumatic events and pathological relations of the immediate family members were not only thetriggering factor, but also maintaining the Trichotillomania symptoms. 2. In accordance with the guidelines of Trichotillomania Learning Center-Scientific Advisory Board (2008), the use of a comprehensive treatment including both the patient - individual psycho-therapy (especially cognitive-behavioral therapy) and pharmacotherapy, as well as her family (family psychotherapy, family mediation, workshops for parents), brought about positive therapeutic effects.

Trichotillomania

Trichotillomania, characterized by the repetitive pulling out of one’s own hair leading to hair loss and functional impairment, has been documented in the medical literature since the 19^th century, but has received scant research attention. Community prevalence studies suggest that trichotillomania is a common disorder with point prevalence estimate of 0.5% to 2.0%. Although recently grouped with OCD in the DSM-5, clinicians need to be aware that trichotillomania and OCD may have less in common than originally thought. In fact, approaches to treating trichotillomania, which include habit reversal therapy and medication (n-acetyl cysteine or olanzapine), are quite different from those used to treat OCD; and some first-line treatments used for OCD appear ineffective for trichotillomania. Based on our clinical experience and research findings, the article recommends several management approaches to trichotillomania.

Associations Between Cerebellar Subregional Morphometry and Alcoholism History in Men and Women

BACKGROUND

Alcoholism has been linked to deficits in cognitive, behavioral, and emotional functions, and the cerebellum is important for optimal functioning of these abilities. However, little is known about how individual differences such as gender and drinking history might influence regional cerebellar abnormalities.

METHODS

Volumetric analyses of the cerebellum and its subregions were performed in relation to the interaction of gender and measures of drinking history. Structural magnetic resonance imaging scans of 44 alcoholic individuals (23 men) and 39 nonalcoholic controls (18 men) were obtained. In addition to measuring total cerebellar gray and white matter volumes, we measured 64 individual cerebellar parcellation units, as well as functionally defined a priori regions of interest that have been shown to correspond to functions impaired in alcoholism.

RESULTS

Total cerebellar white matter volume was smaller in alcoholic relative to nonalcoholic participants. Moreover, volumes of parcellation units varied with drinking history, showing negative associations between years of heavy drinking and the anterior lobe, the vestibulocerebellar lobe, and the spinocerebellar subdivision. The negative association between anterior volume and years of heavy drinking was driven primarily by alcoholic men. Additionally, we observed larger white and gray matter volumes for alcoholic women than for alcoholic men.

CONCLUSIONS

The identification of drinking-related abnormalities in cerebellar subregions lays a foundation that can be utilized to inform how cerebro-cerebellar networks are perturbed in this pathological condition. These results also provide estimates of how gender and individual differences in drinking history can predict cerebellar volumes.

Inhibitory Control in Pediatric Trichotillomania (Hair Pulling Disorder): The Importance of Controlling for Age and Symptoms of Inattention and Hyperactivity

Trichotillomania (hair pulling disorder, HPD) is characterized by significant psychological distress, childhood-onset, and, in adults, certain cognitive deficits such as inhibitory control. A total absence of such literature exists within pediatric HPD samples, including research investigating neurocognitive aspects of disparate pulling-styles. The present study aims to address these gaps in the literature. Youth with HPD and healthy controls (N = 45) were compared on an automated neurocognitive task--stop-signal task (SST)--assessing inhibitory control. Youth with HPD (n = 17), controlling for age and attention issues, were found to perform better on the stop-signal reaction time compared to controls (n = 28). No significant relationships between performance on the SST and HPD severity, distress/impairment, or pulling-styles were noted. Findings from the current study suggest that children with HPD may not exhibit deficits in motor inhibition as compared to controls when the effects of age and attentional problems are controlled.

An interrogation of cognitive findings in pediatric obsessive-compulsive and related disorders

Current findings in the field of psychology have led to increased interest and a new conceptualization of disorders characterized by repetitive behaviors, namely the obsessive compulsive and related disorders (OCRDs). Scant research, however, has sought to collect and categorize the extant research on pediatric OCRDs. Particularly, no adequate review of the pediatric cognitive literature existed until now, despite the clear implication of abnormalities in neuroanatomical structures and cognitive functioning in adult samples. While evidence for cognitive dysfunction in pediatric samples is presented, this paper also suggests that differences in cognitive dysfunction may indeed exist between adults and youth with OCRDs. Specifically, those irregularities present in said youth at varying developmental stages may impact the origination and maintenance of OCRDs across time. Finally, this paper seeks to formulate potential future goals for the research field, particularly through transdiagnostic approaches to processes linked with symptom presentations. This is of particular importance as an improved understanding of the interaction of cognitive function and growth is key to further comprehension of the OCRDs.

Cerebellar gray and white matter volume and their relation with age and manual motor performance in healthy older adults

OBJECTIVES

Functional neuroimaging and voxel-based morphometry studies have confirmed the important role of the cerebellum in motor behavior. However, little is known about the relationship between cerebellar gray (GMv) and white matter (WMv) volume and manual motor performance in aging individuals. This study aims to quantify the relationship between cerebellar tissue volume and manual motor performance.

EXPERIMENTAL DESIGN

To gain more insight into cerebellar function and how it relates to the role of the primary motor cortex (M1), we related cerebellar GMv, WMv, and M1v to manual motor performance in 217 healthy older individuals. Left and right cerebellar GMv and WMv, and M1v were obtained using FreeSurfer. The following motor measures were obtained: grip force, tapping speed, bimanual visuomotor coordination, and manual dexterity.

PRINCIPAL OBSERVATIONS

Significant positive relationships were observed between cerebellar GMv and WMv and grip strength, right cerebellar WMv and right-hand tapping speed, right cerebellar WMv and dexterity, M1v and grip strength, and right M1v and left-hand dexterity, though effect sizes were small.

CONCLUSIONS

Our results show that cerebellar GMv and WMv are differently associated with manual motor performance. These associations partly overlap with the brain-behavior associations between M1 and manual motor performance. Not all observed associations were lateralized (i.e., ipsilateral cerebellar and contralateral M1v associations with motor performance), which could point to age-related neural dedifferentiation. The current study provides new insights in the role of the cerebellum in manual motor performance. In consideration of the small effect sizes replication studies are needed to validate these results.

Impaired response inhibition and excess cortical thickness as candidate endophenotypes for trichotillomania

Trichotillomania is characterized by repetitive pulling out of one's own hair. Impaired response inhibition has been identified in patients with trichotillomania, along with gray matter density changes in distributed neural regions including frontal cortex. The objective of this study was to evaluate impaired response inhibition and abnormal cortical morphology as candidate endophenotypes for the disorder. Subjects with trichotillomania (N = 12), unaffected first-degree relatives of these patients (N = 10), and healthy controls (N = 14), completed the Stop Signal Task (SST), a measure of response inhibition, and structural magnetic resonance imaging scans. Group differences in SST performance and cortical thickness were explored using permutation testing. Groups differed significantly in response inhibition, with patients demonstrating impaired performance versus controls, and relatives occupying an intermediate position. Permutation cluster analysis revealed significant excesses of cortical thickness in patients and their relatives compared to controls, in right inferior/middle frontal gyri (Brodmann Area, BA 47 & 11), right lingual gyrus (BA 18), left superior temporal cortex (BA 21), and left precuneus (BA 7). No significant differences emerged between groups for striatum or cerebellar volumes. Impaired response inhibition and an excess of cortical thickness in neural regions germane to inhibitory control, and action monitoring, represent vulnerability markers for trichotillomania. Future work should explore genetic and environmental associations with these biological markers.

Diagnosis, evaluation, and management of trichotillomania

Trichotillomania, or chronic hairpulling, is a common condition that affects primarily women. The disorder can cause significant psychosocial impairment and is associated with elevated rates of psychiatric comorbidity. In this article, the phenomenology, etiology, assessment, and treatment of the disorder are discussed.

Disordered reward processing and functional connectivity in trichotillomania: a pilot study

BACKGROUND

The neurobiology of Trichotillomania is poorly understood, although there is increasing evidence to suggest that TTM may involve alterations of reward processing. The current study represents the first exploration of reward processing in TTM and the first resting state fMRI study in TTM. We incorporate both event-related fMRI using a monetary incentive delay (MID) task, and resting state fMRI, using two complementary resting state analysis methodologies (functional connectivity to the nucleus accumbens and dual regression within a reward network) in a pilot study to investigate differences in reward processing between TTM and healthy controls (HC).

METHODS

21 unmedicated subjects with TTM and 14 HC subjects underwent resting state fMRI scans. A subset (13 TTM and 12 HC) also performed the MID task.

RESULTS

For the MID task, TTM subjects showed relatively decreased nucleus accumbens (NAcc) activation to reward anticipation, but relative over-activity of the NAcc to both gain and loss outcomes. Resting state functional connectivity analysis showed decreased connectivity of the dorsal anterior cingulate (dACC) to the NAcc in TTM. Dual regression analysis of a reward network identified through independent component analysis (ICA) also showed decreased dACC connectivity and more prominently decreased basolateral amygdala connectivity within the reward network in TTM.

CONCLUSIONS

Disordered reward processing at the level of NAcc, also involving decreased modulatory input from the dACC and the basolateral amygdala may play a role in the pathophysiology of TTM.

White matter integrity in hair-pulling disorder (trichotillomania)

Hair-pulling disorder (trichotillomania, HPD) is a disabling condition that is characterized by repetitive hair-pulling resulting in hair loss. Although there is evidence of structural grey matter abnormalities in HPD, there is a paucity of data on white matter integrity. The aim of this study was to explore white matter integrity using diffusion tensor imaging (DTI) in subjects with HPD and healthy controls. Sixteen adult female subjects with HPD and 13 healthy female controls underwent DTI. Hair-pulling symptom severity, anxiety and depressive symptoms were also assessed. Tract-based spatial statistics were used to analyze data on fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). There were no differences in DTI measures between HPD subjects and healthy controls. However, there were significant associations of increased MD in white matter tracts of the fronto-striatal-thalamic pathway with longer HPD duration and increased HPD severity. Our findings suggest that white matter integrity in fronto-striatal-thalamic pathways in HPD is related to symptom duration and severity. The molecular basis of measures of white matter integrity in HPD deserves further exploration.

Hair pulling disorder (trichotillomania): genes, neurobiology, and a model for understanding impulsivity and compulsivity

Hair pulling disorder (trichotillomania) affects at least 3.7 million people in the United States and results in marked functional impairment. This article reviews empirical research investigating the genetics and neurobiology of hair pulling disorder (HPD). We also discuss recent advances in the characterization of this phenotype which have led to evidence supporting the existence of at least two disparate pulling styles-automatic and focused pulling. These pulling styles exhibit facets of behavioral processes, impulsivity and compulsivity, characteristic of several classes of disorders (e.g., obsessive-compulsive spectrum disorders, impulse control disorders). Available genetic, neurobiological, and clinical data support the importance of impulsivity for conceptualizing HPD. Impulsivity alone is insufficient to fully understand this complex phenotype. Characterizations of both automatic and focused pulling as well as preliminary findings from affective neuroscience across species highlight the importance of compulsivity for understanding HPD. Opposing and complementary aspects to impulsivity-compulsivity provide a more comprehensive conceptualization of HPD and supports HPD's potential importance for advancing scientific inquiry in relation to the pathogenesis and treatment of related phenotypes. This review concludes with a description of areas-phenotype, neurobiology, and genes-in need of further study.

Trichotillomania in a dementia case

We report an 87-year-old male case of hair pulling associated with a white-matter vascular dementia (Binswanger’s disease). Trichotillomania in our case did not resolve using mirtazapine or anticholinesterasic medication. Trichotillomania seems to be related to a form of perseveration associated with dementia. The findings in this case suggest the abnormality involving white matter in the pathogenesis of trichotillomania, may constitute a defect in connectivity in the right frontal-subcortical circuit.

A pilot study of brain activation in children with trichotillomania during a visual-tactile symptom provocation task: a functional magnetic resonance imaging study

OBJECTIVES

In order to reveal the etiology and pathophysiology of trichotillomania (TTM), it is necessary to investigate which brain regions are involved in TTM, but limited knowledge exists regarding the neurobiology of TTM and the available functional neuroimaging studies of TTM are little. The purpose of the present study was to investigate the specific brain regions involved in the pathophysiology of TTM with symptom provocation task using functional magnetic resonance imaging (fMRI) for children and adolescents with TTM.

METHODS

Pediatric subjects who met the DSM-IV TR criteria for TTM (n=9) and age-, sex-, handedness-, IQ matched healthy controls (HC) (n=10), ages 9 to 17 years, were recruited for two fMRI experiments; symptom provocation of Visual Only (VO) and Visual and Tactile (VT). They were scanned while viewing two alternating blocks of symptom provocation (S) and neutral (N) movies.

RESULTS

Random effects between-group analysis revealed significant activation in left temporal cortex(including middle and superior temporal gyrus), dorsal posterior cingulate gyrus, and putamen for the contrast S>N in TTM subjects versus HC subjects during the VO session. And TTM subjects demonstrated higher activity in the precuneus and dorsal posterior cingulate gyrus to the contrast S>N during the VT session.

CONCLUSIONS

This study provided an objective whole-brain-based analysis that directed researchers to areas that were abnormal in TTM. Using the symptom provocation tasks, we found significant differences in regional brain function between pediatric TTM and HC subjects. However, in the face of modest statistical power, our preliminary findings in TTM need to be replicated in a larger sample. As the functional neuroanatomic circuits involved in TTM remain largely unexplored, future functional neuroimaging studies using other various paradigms may help investigate the neuroanatomic abnormalities of TTM.

Trichotillomania (hair pulling disorder), skin picking disorder, and stereotypic movement disorder: toward DSM-V

In DSM-IV-TR, trichotillomania (TTM) is classified as an impulse control disorder (not classified elsewhere), skin picking lacks its own diagnostic category (but might be diagnosed as an impulse control disorder not otherwise specified), and stereotypic movement disorder is classified as a disorder usually first diagnosed in infancy, childhood, or adolescence. ICD-10 classifies TTM as a habit and impulse disorder, and includes stereotyped movement disorders in a section on other behavioral and emotional disorders with onset usually occurring in childhood and adolescence. This article provides a focused review of nosological issues relevant to DSM-V, given recent empirical findings. This review presents a number of options and preliminary recommendations to be considered for DSM-V: (1) Although TTM fits optimally into a category of body-focused repetitive behavioral disorders, in a nosology comprised of relatively few major categories it fits best within a category of motoric obsessive-compulsive spectrum disorders, (2) available evidence does not support continuing to include (current) diagnostic criteria B and C for TTM in DSM-V, (3) the text for TTM should be updated to describe subtypes and forms of hair pulling, (4) there are persuasive reasons for referring to TTM as "hair pulling disorder (trichotillomania)," (5) diagnostic criteria for skin picking disorder should be included in DSM-V or in DSM-Vs Appendix of Criteria Sets Provided for Further Study, and (6) the diagnostic criteria for stereotypic movement disorder should be clarified and simplified, bringing them in line with those for hair pulling and skin picking disorder.

Should an obsessive-compulsive spectrum grouping of disorders be included in DSM-V?

The obsessive-compulsive (OC) spectrum has been discussed in the literature for two decades. Proponents of this concept propose that certain disorders characterized by repetitive thoughts and/or behaviors are related to obsessive-compulsive disorder (OCD), and suggest that such disorders be grouped together in the same category (i.e. grouping, or "chapter") in DSM. This article addresses this topic and presents options and preliminary recommendations to be considered for DSM-V. The article builds upon and extends prior reviews of this topic that were prepared for and discussed at a DSM-V Research Planning Conference on Obsessive-Compulsive Spectrum Disorders held in 2006. Our preliminary recommendation is that an OC-spectrum grouping of disorders be included in DSM-V. Furthermore, we preliminarily recommend that consideration be given to including this group of disorders within a larger supraordinate category of "Anxiety and Obsessive-Compulsive Spectrum Disorders." These preliminary recommendations must be evaluated in light of recommendations for, and constraints upon, the overall structure of DSM-V.

Recent Advances in the Understanding and Treatment of Trichotillomania

Trichotillomania (TTM), or chronic hair pulling, is associated with significant levels of distress and impairment. While research is in its infancy, more data are accumulating regarding the impact, phenomenology, maintaining variables, etiology, and treatment of TTM. Behavior therapy and clomipramine have been moderately effective in reducing TTM symptoms in clinical trials. Enhancing behavior therapy with techniques designed to address TTM patients' emotional control tendencies (e.g., acceptance-based procedures) represents a promising direction in treating TTM.

Tourette's syndrome, trichotillomania, and obsessive-compulsive disorder: how closely are they related?

The question of whether Tourette's syndrome (TS) and trichotillomania (TTM) are best conceptualized as obsessive-compulsive spectrum disorders was raised by family studies demonstrating a close relationship between TS and obsessive-compulsive disorder (OCD), and by psychopharmacological research indicating that both TTM and OCD respond more robustly to clomipramine than to desipramine. A range of studies have subsequently allowed comparison of the phenomenology, psychobiology, and management of TS and TTM, with that of OCD. Here we briefly review this literature. The data indicate that there is significant psychobiological overlap between TS and OCD, supporting the idea that TS can be conceptualized as an OCD spectrum disorder. TTM and OCD have only partial overlap in their phenomenology and psychobiology, but there are a number of reasons for why it may be useful to classify TTM and other habit disorders as part of the obsessive-compulsive spectrum of disorders.

Trichotillomania: A current review

This review provides a broad and thorough synthesis of the Trichotillomania (TTM) literature as a resource for health professionals seeking the most current and complete information available. For the treatment provider, up to date information can help inform assessment, treatment, or referral decisions. For the student, this review provides a general overview and broad background information necessary to better understand hair-pulling and associated problems. For the researcher, information can help inform study planning. Prevalence, gender distributions, comorbidities, subtypes, and phenomenological characteristics are presented. Etiological theories are reviewed, and assessment and treatment options are offered. The validity of current DSM requirements is discussed and psychological and psychiatric treatment options are presented and evaluated for their strength of recommendation. Challenges to research and treatment are presented and directions for future research are suggested.

Sapap3 and pathological grooming in humans: Results from the OCD collaborative genetics study

SAP90/PSD95-associated protein (SAPAP) family proteins are post-synaptic density (PSD) components that interact with other proteins to form a key scaffolding complex at excitatory (glutamatergic) synapses. A recent study found that mice with a deletion of the Sapap3 gene groomed themselves excessively, exhibited increased anxiety-like behaviors, and had cortico-striatal synaptic defects, all of which were preventable with lentiviral-mediated expression of Sapap3 in the striatum; the behavioral abnormalities were also reversible with fluoxetine. In the current study, we sought to determine whether variation within the human Sapap3 gene was associated with grooming disorders (GDs: pathologic nail biting, pathologic skin picking, and/or trichotillomania) and/or obsessive-compulsive disorder (OCD) in 383 families thoroughly phenotyped for OCD genetic studies. We conducted family-based association analyses using the FBAT and GenAssoc statistical packages. Thirty-two percent of the 1,618 participants met criteria for a GD, and 65% met criteria for OCD. Four of six SNPs were nominally associated (P < 0.05) with at least one GD (genotypic relative risks: 1.6-3.3), and all three haplotypes were nominally associated with at least one GD (permuted P < 0.05). None of the SNPs or haplotypes were significantly associated with OCD itself. We conclude that Sapap3 is a promising functional candidate gene for human GDs, though further work is necessary to confirm this preliminary evidence of association.

Grey matter abnormalities in trichotillomania: morphometric magnetic resonance imaging study

BACKGROUND

Trichotillomania (repetitive hair-pulling) is an Axis I psychiatric disorder whose neurobiological basis is incompletely understood. Whole-brain trichotillomania neuroimaging studies are lacking.

AIMS

To investigate grey and white matter abnormalities over the whole brain in patients with trichotillomania.

METHOD

Eighteen patients with DSM-IV trichotillomania and 19 healthy controls undertook structural magnetic resonance imaging after providing written informed consent. Differences in grey and white matter were investigated using computational morphometry.

RESULTS

Patients with trichotillomania showed increased grey matter densities in the left striatum, left amygdalo-hippocampal formation, and multiple (including cingulate, supplementary motor, and frontal) cortical regions bilaterally.

CONCLUSIONS

Trichotillomania was associated with structural grey matter changes in neural circuitry implicated in habit learning, cognition and affect regulation. These findings inform animal models of the disorder and highlight key regions of interest for future translational research.

Psychobiology of anxiety disorders and obsessive-compulsive spectrum disorders

Obsessive-compulsive disorder is currently classified as an anxiety disorder. However, there is growing interest in the concept of an obsessive-compulsive spectrum of disorders (OCSDs). The relationship between anxiety disorders and OCSDs has been questioned. The psychobiology of anxiety disorders and OCSDs is briefly reviewed in this article. While there appear to be several distinct contrasts in the underlying psychobiology of these conditions, there is also evidence of overlapping mechanisms. In addition, there are crucial gaps in our current database, confounding nosological decision-making. Conceptualizing various anxiety disorders and putative OCSDs as lying within a broader spectrum of emotional disorders may be useful. However, clinicians must also recognize that individual anxiety and obsessive-compulsive spectrum conditions, including disorders characterized by body-focused repetitive behaviors, have distinct psychobiological underpinnings and require different treatment approaches.

Obsessive-compulsive disorder: boundary issues

The boundaries between obsessive-compulsive disorder (OCD) and other neuropsychiatric disorders remain unresolved and may well differ from one disorder to another. Endophenotypes are heritable, quantitative traits hypothesized to more closely represent genetic risk for complex polygenic mental disorders than overt symptoms and behaviors. They may have a role in identifying how closely these disorders are associated with another and with other mental disorders with which they share major comorbidity. This review maps the nosological relationships of OCD to other neuropsychiatric disorders, using OCD as the prototype disorder and endophenotype markers, such as cognitive, imaging, and molecular data as well as results from demographic, comorbidity, family, and treatment studies. Despite high comorbidity rates, emerging evidence suggests substantial endophenotypic differences between OCD and anxiety disorders, depression, schizophrenia, and addictions, though comparative data is lacking and the picture is far from clear. On the other hand, strong relationships between OCD, Tourette syndrome, body dysmorphic disorder, hypochondriasis, grooming disorders, obsessive-compulsive personality disorder, and pediatric autoimmune neuropsychiatric disorders associated with streptococcus are likely. Studies designed to delineate the cause, consequences, and common factors are a challenging but essential goal for future research in this area.

Brain activation during implicit sequence learning in individuals with trichotillomania

Trichotillomania (TTM) may be related to obsessive-compulsive disorder (OCD) and other neuropsychiatric conditions characterized by cortico-striatal dysfunction. Functional imaging studies of OCD using an implicit learning task have found abnormalities in striatal and hippocampal activation. The current study investigated whether similar abnormalities occur in TTM. Functional MRI and the serial reaction time (SRT) task were used to assess striatal and hippocampal activation during implicit sequence learning in TTM and healthy control (HC) subjects. The results for 20 age- and education-matched participants (10 TTM, 10 HC) are reported. In comparison with HC participants, those with TTM exhibited no significant differences in implicit learning, or in activation within the striatum, hippocampus, or other brain regions. The current findings do not provide evidence for cortico-striatal dysfunction in TTM. Future studies directly comparing OCD and TTM subjects are warranted to confirm the specificity of abnormal striatal and hippocampal findings during implicit sequence learning in OCD.