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Concept: Trichotillomania


The self-induced dermatoses (such as trichotillomania, pathologic skin picking or neurotic excoriations, dermatitis artefacta, onychophagia and onychotillomania), which are caused as a result of excessive manipulation of the skin, hair, and nails by the patient, can contribute to significant morbidity and can even complicate the course of a primary dermatologic condition such as acne (eg, in acne excoriée) and some pruritic dermatoses. Reports on the self-induced dermatoses in the past decade have tended to focus upon the specific motor behaviors involved in self-inducing the lesions (ie, skin picking or hair pulling) rather than address the common psychopathologic factors underlying the self-injurious behaviors. In the current psychiatric nosology (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision) the self-induced dermatoses are classified as Impulse Control Disorders and Stereotypic Movement Disorders, and this classification does not adequately consider the fact that in most patients with self-induced dermatoses, the frequency and severity of the self-injurious behaviors are directly related to acute or chronic problems with emotional regulation and dissociation. This may be part of the reason that there is a relative paucity of effective treatments for these disorders. The skin and its appendages are well innervated with a dense network of afferent sensory nerves and efferent autonomic nerves, and the integumentary system is frequently the focus of tension-reducing and emotion-regulating behaviors, especially during states of autonomic nervous system hyperarousal. This factor is important in the pathogenesis of the self-induced dermatoses. Mood-stabilizing agents, such as lithium carbonate, that are used to treat disorders of emotional regulation have not been adequately studied in the management of the self-induced dermatoses and may prove to be very helpful in the management of these disorders.

Concepts: Nervous system, Psychology, Mental disorder, Bipolar disorder, Psychiatry, Trichotillomania, Impulse control disorder, Dermatillomania


Body-focused repetitive behavior (BFRB) is an umbrella term for debilitating, repetitive behaviors that target one or more body regions. Despite regularly occurring in youth, there has been limited investigation of BFRBs in pediatric populations. One reason for this may be that there are few reliable and valid assessments available to evaluate the presence, severity and impairment of BFRBs in youth. Given the shift toward evidence-based assessment in mental health, the development and utilization of evidence-based measures of BFRBs warrants increasing attention. This paper examines the available evidence-base for assessments in youth across three BFRB-related disorders: compulsive skin picking, chronic tic disorders and trichotillomania. Based upon present empirical support in samples of youth, recommendations are made for an evidence-based assessment of each condition.

Concepts: Psychology, Educational psychology, Tic disorder, Trichotillomania, Body-focused repetitive behavior, Impulse control disorder, Dermatillomania, Dermatophagia


Body-focused repetitive behaviors (BFRBs), including hair pulling, nail biting, and skin picking are repetitive, habitual, and compulsive in nature. Although characteristic of disorders such as trichotillomania and skin picking disorder, BFRBs are associated with other psychiatric conditions as well. To date, research has failed to examine neurocognitive risk factors, particularly executive functioning, implicated in BFRBs utilizing a transdiagnostic approach. The present study recruited 53 participants (n = 27 demonstrating BFRBs and n = 26 randomly selected controls) from a larger sample of young adults. Participants completed an automated neurocognitive test battery including tasks of cognitive flexibility, working memory, and planning and organization. Results revealed that participants in the BFRB group demonstrated significantly poorer cognitive flexibility (d = 0.63) than controls. No differences were noted in other neurocognitive domains. However, planning and organization demonstrated a significant relationship with various BFRB severity measures. Implications, limitations, and avenues for further research are discussed.

Concepts: Psychology, Working memory, Executive functions, Trichotillomania, Body-focused repetitive behavior, Impulse control disorder, Dermatillomania, Dermatophagia


Rapunzel syndrome is an extremely rare condition associated with trichophagia (hair eating disorder) secondary to a psychiatric illness called trichotillomania (hair-pulling behaviour). It is most commonly seen in children and adolescents. Untreated cases can lead to a number of complications. We present a case of a middle-aged woman with sudden intractable vomiting and constipation associated with bilateral pedal oedema and significant weight loss. Laboratory investigations revealed low serum protein levels. Laparotomy was performed, and a hairball was removed from her stomach and ileum. The patient was managed with the help of a psychiatrist and was given nutritional support. We performed a comprehensive search and summarised data for a total of 88 cases. No time or language limit was placed. The purpose of this discussion is to highlight the clinical spectrum of Rapunzel syndrome and also to report its rare association with hypoproteinaemia.

Concepts: Nutrition, Eating disorders, Psychiatry, Serum total protein, Serum protein electrophoresis, Rapunzel syndrome, Trichotillomania, Trichophagia


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.

Concepts: Brain, Magnetic resonance imaging, Cerebral cortex, Thermodynamics, Mental disorder, Inferior frontal gyrus, Obsessive–compulsive disorder, Trichotillomania


Skin Picking Disorder affects 4% of the general population, with serious quality of life impacts, and potentially life threatening complications. Standard psychoactive medications do not help most patients. Similarly, Mouse Ulcerative Dermatitis (skin lesions caused by excessive abnormal grooming behavior) is very common in widely used inbred strains of mice, and represents a serious animal welfare issue and cause of mortality. Treatment options for Ulcerative Dermatitis are largely palliative and ineffective. We have proposed mouse Ulcerative Dermatitis as a model for human Skin Picking Disorder based on similar epidemiology, behavior, and its comorbidity and mechanistic overlap with hair pulling (trichotillomania). We predicted that mouse Ulcerative Dermatitis would be treated by N-Acetylcysteine, as this compound is highly effective in treating both Skin Picking Disorder and Trichotillomania. Furthermore, we hypothesized that N-Acetylcysteine’s mode of action is as a precursor to the production of the endogenous antioxidant glutathione in the brain, and therefore intranasal glutathione would also treat Ulcerative Dermatitis. Accordingly, we show in a heterogenous prospective trial, the significant reduction in Ulcerative Dermatitis lesion severity in mice receiving either N-acetylcysteine (oral administration) or glutathione (intranasal). The majority of mice treated with N-acetylcysteine improved slowly throughout the course of the study. Roughly half of the mice treated with glutathione showed complete resolution of lesion within 2-4 weeks, while the remainder did not respond. These findings are the first to show that the use of N-acetylcysteine and Glutathione can be curative for mouse Ulcerative Dermatitis. These findings lend additional support for mouse Ulcerative Dermatitis as a model of Skin Picking Disorder and also support oxidative stress and glutathione synthesis as the mechanism of action for these compounds. As N-Acetylcysteine is poorly tolerated by many patients, intranasal glutathione warrants further study as potential therapy in Skin Picking, trichotillomania and other body-focused repetitive behavior disorders.

Concepts: Oxidative stress, Glutathione, Psychoactive drug, Trichotillomania, Body-focused repetitive behavior, Impulse control disorder, Dermatillomania, Dermatophagia


Little is known about the etiology of hair pulling (HP) and its relationship to other obsessive compulsive (OC) spectrum disorders. In a large-sample family study, we examined the familial aggregation of HP and co-transmission of obsessive compulsive disorder (OCD) and skin picking (SP). Our sample consisted of 110 proband cases with HP and 48 controls without HP, plus 128 first-degree case relatives and 50 first-degree control relatives. Case versus control relatives had higher recurrence risk estimates for both HP and OCD but not SP. The finding that HP is familial is consistent with the only existing twin study. Additional analyses suggest that there may be a familial subtype of HP with comorbid OCD. Those adult proband cases with HP + OCD had more anxiety and depression than cases without OCD. Probands with HP + OCD also had earlier onset of OCD. Identification of an HP subtype with comorbid OCD may have significant theoretical and treatment implications. The data did not provide evidence for an etiologic relationship between HP and SP. Replication of these findings in future studies with larger cohorts of case and control relatives is warranted. © 2014 Wiley Periodicals, Inc.

Concepts: Anxiety, Scientific method, Selective serotonin reuptake inhibitor, Body dysmorphic disorder, Anxiety disorders, Obsessive–compulsive disorder, Trichotillomania


Obsessive compulsive disorder (OCD) is a syndrome characterized by recurrent and intrusive thoughts and ritualistic behaviors or mental acts that a person feels compelled to perform. Twin studies, family studies, and segregation analyses provide compelling evidence that OCD has a strong genetic component. The SLITRK1 gene encodes a developmentally regulated stimulator of neurite outgrowth and previous studies have implicated rare variants in this gene in disorders in the OC spectrum, specifically Tourette syndrome (TS) and trichotillomania (TTM). The objective of the current study was to evaluate rare genetic variation in SLITRK1 in risk for OCD and to functionally characterize associated coding variants. We sequenced SLITRK1 coding exons in 381 individuals with OCD as well as in 356 control samples and identified three novel variants in seven individuals. We found that the combined mutation load in OCD relative to controls was significant (p = 0.036). We identified a missense N400I change in an individual with OCD, which was not found in more than 1000 control samples (P<0.05). In addition, we showed the the N400I variant failed to enhance neurite outgrowth in primary neuronal cultures, in contrast to wildtype SLITRK1, which enhanced neurite outgrowth in this assay. These important functional differences in the N400I variant, as compared to the wildtype SLITRK1 sequence, may contribute to OCD and OC spectrum symptoms. A synonymous L63L change identified in an individual with OCD and an additional missense change, T418S, was found in four individuals with OCD and in one individual without an OCD spectrum disorder. Examination of additional samples will help assess the role of rare SLITRK1 variation in OCD and in related psychiatric illness.

Concepts: Tourette syndrome, Body dysmorphic disorder, Obsessive–compulsive disorder, Compulsive hoarding, Trichotillomania


Trichotillomania/hair pulling disorder (HPD) and excoriation/skin picking disorder (SPD) are childhood-onset, body-focused repetitive behaviors that are thought to share genetic susceptibility and underlying pathophysiology with obsessive-compulsive disorder (OCD) and Tourette syndrome (TS). We sought to determine the prevalence of DSM-5 HPD and SPD in TS patients, and to identify clinical factors most associated with their co-morbidity with TS. Participants included 811 TS patients recruited from TS specialty clinics for a multi-center genetic study. Patients were assessed using standardized, validated semi-structured interviews. HPD and SPD diagnoses were determined using a validated self-report questionnaire. HPD/SPD prevalence rates were calculated, and clinical predictors were evaluated using regression modeling. 3.8 and 13.0% of TS patients met DSM-5 criteria for HPD and SPD, respectively. In univariable analyses, female sex, OCD, and both tic and obsessive-compulsive symptom severity were among those associated with HPD and/or SPD. In multivariable analyses, only lifetime worst-ever motor tic severity remained significantly associated with HPD. Female sex, co-occurring OCD, ADHD, and motor tic severity remained independently associated with SPD. This is the first study to examine HPD and SPD prevalence in a TS sample using semi-structured diagnostic instruments. The prevalence of HPD and SPD in TS patients, and their association with increased tic severity and co-occurring OCD, suggests that clinicians should screen children with TS and related disorders for HPD/SPD, particularly in females and in those with co-occurring OCD. This study also helps set a foundation for subsequent research regarding HPD/SPD risk factors, pathophysiology, and treatment models.

Concepts: Sex, Tourette syndrome, Tic, Obsessive–compulsive disorder, Trichotillomania


Hoxb8 mutant mice exhibit compulsive grooming and hair removal dysfunction similar to humans with the obsessive-compulsive disorder (OCD)-spectrum disorder, trichotillomania. As, in the mouse brain, the only detectable cells that label with Hoxb8 cell lineage appear to be microglia, we suggested that defective microglia cause the neuropsychiatric disorder. Does the Hoxb8 mutation in microglia lead to neural circuit dysfunctions? We demonstrate that Hoxb8 mutants contain corticostriatal circuit defects. Golgi staining, ultra-structural and electrophysiological studies of mutants reveal excess dendritic spines, pre- and postsynaptic structural defects, long-term potentiation and miniature postsynaptic current defects. Hoxb8 mutants also exhibit hyperanxiety and social behavioral deficits similar to mice with neuronal mutations in Sapap3, Slitrk5 and Shank3, reported models of OCD and autism spectrum disorders (ASDs). Long-term treatment of Hoxb8 mutants with fluoxetine, a serotonin reuptake inhibitor, reduces excessive grooming, hyperanxiety and social behavioral impairments. These studies provide linkage between the neuronal defects induced by defective Hoxb8-microglia and neuronal dysfunctions directly generated by mutations in synaptic components that result in mice, which display similar pathological grooming, hyperanxiety and social impairment deficits. Our results shed light on Hoxb8 microglia-driven circuit-specific defects and therapeutic approaches that will become essential to developing novel therapies for neuropsychiatric diseases such as OCD and ASDs with Hoxb8-microglia being the central target.Molecular Psychiatry advance online publication, 26 September 2017; doi:10.1038/mp.2017.180.

Concepts: Nervous system, Neuron, Autism, Dendrite, Fluvoxamine, Selective serotonin reuptake inhibitor, Obsessive–compulsive disorder, Trichotillomania