A twin concordance study of trichotillomania

The genetics of trichotillomania and excoriation disorder: A systematic review

BACKGROUND

Trichotillomania (TTM) and excoriation disorder (ED) are impairing obsessive-compulsive related disorders that are common in the general population and for which there are no clear first-line medications, highlighting the need to better understand the underlying biology of these disorders to inform treatments. Given the importance of genetics in obsessive-compulsive disorder (OCD), evaluating genetic factors underlying TTM and ED may advance knowledge about the pathophysiology of these body-focused repetitive behaviors.

AIM

In this systematic review, we summarize the available evidence on the genetics of TTM and ED and highlight gaps in the field warranting further research.

METHOD

We systematically searched Embase, PsycInfo, PubMed, Medline, Scopus, and Web of Science for original studies in genetic epidemiology (family or twin studies) and molecular genetics (candidate gene and genome-wide) published up to June 2023.

RESULTS

Of the 3536 records identified, 109 studies were included in this review. These studies indicated that genetic factors play an important role in the development of TTM and ED, some of which may be shared across the OCD spectrum, but there are no known high-confidence specific genetic risk factors for either TTM or ED.

CONCLUSIONS

Our review underscores the need for additional genome-wide research conducted on the genetics of TTM and ED, for instance, genome-wide association and whole-genome/whole-exome DNA sequencing studies. Recent advances in genomics have led to the discovery of risk genes in several psychiatric disorders, including related conditions such as OCD, but to date, TTM and ED have remained understudied.

Genomics of Obsessive-Compulsive Disorder and Related Disorders: What the Clinician Needs to Know

A wealth of evidence has shown that genetics plays a major role in susceptibility to obsessive-compulsive disorder (OCD) and all of its related disorders. Several large-scale, collaborative efforts using modern genomic methods are beginning to reveal the genetic architecture of these traits and identify long-sought risk genes. In this article, we summarize current OCD and related disorder genomic knowledge and explain how to communicate this information to patients and their families. The article concludes with a discussion of how genomic discovery in OCD and related disorders can inform our understanding of disease etiology and provide novel targets for therapeutic development.

Amelioration of trichotillomania with onabotulinumtoxinA for chronic migraine

We report a case of a woman in her 30s who struggled with a life-long history of trichotillomania (TTM; hair-pulling disorder), which was unsuccessfully treated with behavioural therapy and selective serotonin reuptake inhibitors. In addition to TTM, our patient had a history of chronic migraine which brought her to our clinic, and treatment with onabotulinumtoxinA (OBTA) was initiated per the Phase III REsearch Evaluating Migraine Prophylaxis Therapy protocol. After experiencing improvement with migraine symptoms, she began off-label treatment with OBTA for her TTM with 45 units being injected, 5 units per site, in diffuse regions of her scalp, primarily on the affected areas of TTM-induced alopecia. The patient reported marked improvement in her TTM signs and symptoms, which resulted in hair regrowth as early as the first follow-up visit 12 weeks post-treatment initiation. Treatment effects were maintained, and additional hair regrowth was observed at the 1-year post-treatment visit, which equated to four cycles of treatment.

The Sapap3-/- mouse reconsidered as a comorbid model expressing a spectrum of pathological repetitive behaviours

Symptom comorbidity is present amongst neuropsychiatric disorders with repetitive behaviours, complicating clinical diagnosis and impeding appropriate treatments. This is of particular importance for obsessive-compulsive disorder (OCD) and Tourette syndrome. Here, we meticulously analysed the behaviour of Sapap3 knockout mice, the recent rodent model predominantly used to study compulsive-like behaviours, and found that its behaviour is more complex than originally and persistently described. Indeed, we detected previously unreported elements of distinct pathologically repetitive behaviours, which do not form part of rodent syntactic cephalo-caudal self-grooming. These repetitive behaviours include sudden, rapid body and head/body twitches, resembling tic-like movements. We also observed that another type of repetitive behaviour, aberrant hindpaw scratching, might be responsible for the flagship-like skin lesions of this mouse model. In order to characterise the symptomatological nature of observed repetitive behaviours, we pharmacologically challenged these phenotypes by systemic aripiprazole administration, a first-line treatment for tic-like symptoms in Tourette syndrome and trichotillomania. A single treatment of aripiprazole significantly reduced the number of head/body twitches, scratching, and single-phase grooming, but not syntactic grooming events. These observations are in line with the high comorbidity of tic- and compulsive-like symptoms in Tourette, OCD and trichotillomania patients.

Sociodemographic variables, clinical characteristics, and treatments in children with trichotillomania in terms of age and gender: a multicenter study

OBJECTIVE

Although trichotillomania (TTM) is a common, typically pediatric-onset disorder, data on the phenomenology of TTM in children, accompanying comorbid psychiatric disorders, and treatment options are extremely limited. In our study, it was aimed to investigate these variables and related factors in patients undergoing psychiatric evaluation and follow-up.

METHOD

The study included 79 children and adolescents between the ages of 4 and 17 who were diagnosed with TTM and followed up in four different Child and Adolescent Psychiatry outpatient clinics between 2015 and 2020. The sociodemographic characteristics of these patients, clinical features of the disease, comorbid psychiatric disorders, and treatment approaches have been studied.

RESULTS

Our results showed that TTM was more common in girls, hair and eyebrow plucking was the most common, and symptoms and features accompanying TTM changed with age, but not with gender. Again, 79.7% of these children had at least one psychiatric comorbid disorder (most common being anxiety disorders and Attention Deficit/Hyperactivity Disorder), comorbidity was closely related to TTM severity, 93.7% used at least one pharmacotherapeutic agent, and positive response rates to treatment were found to be low. Moreover, TTM severity was found to increase with age and disease duration.

CONCLUSION

Study findings support that clinical presentation, disease severity and comorbidity rates may change with age in children and adolescents with TTM, and early intervention is important to prevent clinical progression/worsening and mental health sequela.

Significance of family history in understanding and subtyping trichotillomania

BACKGROUND AND AIMS

The existence of subtypes of trichotillomania (TTM) have long been hypothesized, and recent studies have further elucidated characteristic subtypes of TTM and possible ramifications of subtyping for treatment. In clinical applications of subtyping for treatment of TTM, family history (FH) of psychiatric disorders in patients may serve as a tool to differentiate disorder presentations and inform care. We compared prevalence of psychiatric illnesses in first-degree relatives of participants with TTM and healthy controls, respectively, in a large sample, and examined associations between those psychiatric disorders that were significantly different in the FH between groups and measures of disability, severity, and neuropsychological constructs.

METHODS

We compared FHs of 152 participants (mean age = 29.9) with TTM and 71 healthy controls (mean age = 29.6), utilizing chi-squared tests to determine which psychiatric illnesses were more prevalent in FHs of participants with TTM. We then used two-tailed t-tests to compare TTM participants with those more prevalent FHs to participants without those FHs on measures of disorder severity, disability, and neuropsychological constructs.

FINDINGS

Obsessive-compulsive disorder (OCD), TTM, skin picking disorder (SPD), and major depressive disorder (MDD) were significantly more frequent in first-degree relatives (p < 0.0033) of TTM participants than those of healthy controls. TTM participants with a FH of OCD scored significantly higher on measures of impulsivity and lower on measures of distress tolerance. Those with FH of TTM, SPD, and MDD did not differ significantly across measured variables.

CONCLUSION

OCD, TTM, SPD, and MDD are more prevalent in the FHs of people with TTM, as compared to healthy controls. TTM participants with a family history of OCD may be more likely to demonstrate decreased distress tolerance and increased impulsivity. In all, as understanding of TTM subtypes develops, the FH may prove a useful tool in delineating subtypes and informing care.

What Have We Learned About the Genetics of Obsessive-Compulsive and Related Disorders in Recent Years?

Obsessive-compulsive disorder (OCD) is a complex, multifactorial disorder with onset in either childhood or early adulthood. Lifetime prevalence has been estimated to be around 2%-3%. DSM-5 groups OCD together with closely related disorders-body dysmorphic disorder, trichotillomania (hair-pulling disorder), hoarding disorder, and excoriation disorder (skin-picking disorder)-as obsessive-compulsive and related disorders (OCRDs). In addition, DSM-5 includes a "tic-related" specifier, recognizing that OCD and Tourette syndrome/chronic tics are frequently comorbid. In recent years, the first large-scale genome-wide studies of OCRDs have emerged. These studies confirmed results from earlier twin and family studies that have demonstrated a strong genetic component to OCRDs. Furthermore, from analyses of common genetic variation, these studies offered a first insight into how the genetic risk of developing an OCRD might be connected to the genetic risk of developing another OCRD. This article is an update of the authors' previous report; it summarizes recent findings on the genetics of OCRDs and highlights some of the recent directions in OCRD genetics that will pave the way for new insights into OCRD pathophysiology.

A dimensional perspective on the genetics of obsessive-compulsive disorder

This review covers recent findings in the genomics of obsessive-compulsive disorder (OCD), obsessive-compulsive symptoms, and related traits from a dimensional perspective. We focus on discoveries stemming from technical and methodological advances of the past five years and present a synthesis of human genomics research on OCD. On balance, reviewed studies demonstrate that OCD is a dimensional trait with a highly polygenic architecture and genetic correlations to multiple, often comorbid psychiatric phenotypes. We discuss the phenotypic and genetic findings of these studies in the context of the dimensional framework, relying on a continuous phenotype definition, and contrast these observations with discoveries based on a categorical diagnostic framework, relying on a dichotomous case/control definition. Finally, we highlight gaps in knowledge and new directions for OCD genetics research.

Genetics of OCD and Related Disorders; Searching for Shared Factors

Obsessive compulsive disorder (OCD) and several other obsessive-compulsive related disorders (OCRDs) including hoarding disorder, body dysmorphic disorder (BDD), skin picking disorder, trichotillomania and the newly arising public health conditions of online gaming and gambling disorders, under the umbrella of Problematic Usage of the Internet (PUI), not only share some common phenotypes, but there is evidence to suggest share some genetic risk factors. The simple fact that these disorders segregate within families points to this notion. However, the current data are still scarce. This chapter focuses on identifying the shared genetic factors. To address this question, a systematic review of the literature investigating genetic findings in OCD and OCRDs including PUI was conducted, with a focus on their genetic similarities. Greater knowledge of the specific genetic risks shared among OCRDs would be expected to open new avenues in the understanding of the biological mechanisms causing the development of these phenotypes, as well as provide opportunities to develop new animal and cellular models testing new therapy avenues.

“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.

Pathological grooming: Evidence for a single factor behind trichotillomania, skin picking and nail biting

Although trichotillomania (TTM), skin picking (SP), and nail biting (NB) have been receiving growing scientific attention, the question as to whether these disorders can be regarded as separate entities or they are different manifestations of the same underlying tendency is unclear. Data were collected online in a community survey, yielding a sample of 2705 participants (66% women, mean age: 29.1, SD: 8.6). Hierarchical factor analysis was used to identify a common latent factor and the multiple indicators and multiple causes (MIMIC) modelling was applied to test the predictive effect of borderline personality disorder symptoms, impulsivity, distress and self-esteem on pathological grooming. Pearson correlation coefficients between TTM, SP and NB were between 0.13 and 0.29 (p < 0.01). The model yielded an excellent fit to the data (CFI = 0.992, TLI = 0.991, χ2 = 696.65, p < 0.001, df = 222, RMSEA = 0.030, Cfit of RMSEA = 1.000), supporting the existence of a latent factor. The MIMIC model indicated an adequate fit (CFI = 0.993, TLI = 0.992, χ2 = 655.8, p < 0.001, df = 307, RMSEA = 0.25, CI: 0.022-0.028, pclose = 1.000). TTM, SP and NB each were loaded significantly on the latent factor, indicating the presence of a general grooming factor. Impulsivity, psychiatric distress and contingent self-esteem had significant predictive effects, whereas borderline personality disorder had a nonsignificant predictive effect on the latent factor. We found evidence that the category of pathological grooming is meaningful and encompasses three symptom manifestations: trichotillomania, skin picking and nail biting. This latent underlying factor is not better explained by indicators of psychopathology, which supports the notion that the urge to self-groom, rather than general psychiatric distress, impulsivity, self-esteem or borderline symptomatology, is what drives individual grooming behaviours.

Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics

OBJECTIVES

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Body focused repetitive behavior disorders: Significance of family history

BACKGROUND

The significance of family history in body-focused repetitive behavior disorders (BFRBs) (i.e. trichotillomania and skin picking) has received scant research attention. We sought to understand the clinical and cognitive impact of having a first-degree relative with a BFRB or a substance use disorder (SUD).

METHODS

265 participants with BFRBs undertook clinical and neurocognitive evaluations. Those with a first-degree relative with a BFRB or an SUD were compared to those without on a number of clinical and cognitive measures.

RESULTS

77 (29.1%) participants had a first-degree family member with a BFRB and 59 (22.2%) had a first-degree family member with an SUD. In terms of clinical severity, the amount of time spent picking or pulling per day in the past week was higher among those with a first-degree relative with an SUD. There were a higher rate of ADHD and higher HAM-D scores among those with a positive family history of an SUD. There were no significant cognitive differences based on family history.

CONCLUSIONS

These results indicate that among those with BFRBs, having a first-degree family member with an SUD may be associated with a unique clinical and cognitive presentation. Whether family history also is associated with differential response to treatments awaits further research.

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.

Genetics of obsessive-compulsive disorder and related disorders

Twin and family studies support a significant genetic contribution to obsessive-compulsive disorder (OCD) and related disorders, such as chronic tic disorders, trichotillomania, skin-picking disorder, body dysmorphic disorder, and hoarding disorder. Recently, population-based studies and novel laboratory-based methods have confirmed substantial heritability in OCD. Genome-wide association studies and candidate gene association studies have provided information on specific gene variations that may be involved in the pathobiology of OCD, though a substantial portion of the genetic risk architecture remains unknown.

Pharmacogenetics of antidepressant treatment in obsessive–compulsive disorder: an update and implications for clinicians

Obsessive–compulsive disorder (OCD) is a chronic neuropsychiatric disorder with high genetic influence. Antidepressants such as serotonin reuptake inhibitors, are widely accepted as the first-line medications for OCD; however, approximately 50% of OCD patients show poor response. Personalized medicine utilizing genetic testing has recently received much attention because the variability of antidepressant response and tolerability are partly due to an individual’s genetic variations. This has led to researchers investigating the role of specific genetic factors on antidepressant response and utility of testing in the clinical realm. Genetic test panels are showing promise for guiding antidepressant treatment to improve outcomes in depression. This article will review the most recent findings in the pharmacogenetics of OCD and its related disorders. Promising results have been reported for several serotonergic and glutamatergic system genes and the cytochrome CYP450 liver enzyme genes, which appear to play an important role in OCD and antidepressant response.

A family study of trichotillomania and chronic hair pulling

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.

Animal models of obsessive-compulsive spectrum disorders

Obsessive-compulsive disorder (OCD) and related conditions (trichotillomania, pathological skin-picking, pathological nail-biting) are common and disabling. Current treatment approaches fail to help a significant proportion of patients. Multiple tiers of evidence link these conditions with underlying dysregulation of particular cortico-subcortical circuitry and monoamine systems, which represent targets for treatment. Animal models designed to capture aspects of these conditions are critical for several reasons. First, they help in furthering our understanding of neuroanatomical and neurochemical underpinnings of the obsessive-compulsive (OC) spectrum. Second, they help to account for the brain mechanisms by which existing treatments (pharmacotherapy, psychotherapy, deep brain stimulation) exert their beneficial effects on patients. Third, they inform the search for novel treatments. This article provides a critique of key animal models for selected OC spectrum disorders, beginning with initial work relating to anxiety, but moving on to recent developments in domains of genetic, pharmacological, cognitive, and ethological models. We find that there is a burgeoning literature in these areas with important ramifications, which are considered, along with salient future lines of research.

Familial trichotillomania in three generations

Trichotillomania (TTM) is a type of impulse control disorder, characterized by recurrent pulling of hair. The etiology of TTM is complex, but a genetic contribution to this condition was advocated based on a limited number of reports on familial TTM. We report a 13-year-old male with history of focal hair loss in the scalp. Examination showed a patchy area of hair loss, with several short broken hairs of varying lengths. Dermoscopy and pathology examinations were consistent with TTM. Upon further questioning, his father admitted repeated pulling of his beard. The paternal grandfather also suffers from severe hair pulling of his beard since puberty. To our knowledge, this is the first report of TTM in a 3 generation family. This report strengthens the possibility that TTM is a genetic disease, probably with a complex inheritance pattern. It also highlights the importance of appropriate family history taking when examining a TTM patient.

The genetic factors influencing the development of trichotillomania

Trichotillomania (TTM), an obsessive-compulsive spectrum disorder (OCSD), is a psychiatric condition characterized by repetitive hair pulling. Evidence from family and twin studies suggest a heritable link of TTM. Functional polymorphisms in genes involved in neuronal pathways might influence the susceptibility to TTM. This review is an attempt to compile the genetic factors reported to modify the development of TTM.

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.

The Frequency and Clinical Significance of Twin Gestations According to Zygosity and Chorionicity

Background:Although the clinical importance of chorionicity in twin pregnancies has been studied widely, the significance of perinatal determination of zygosity using molecular genetic analyses remains controversial. The purpose of this study was to determine the frequency and clinical significance of twin gestations according to zygosity and chorionicity in a Korean population.Methods:We enrolled 569 women who delivered twin newborns (> 24 weeks) at Seoul National University Hospital between 1999 and 2008. Chorionicity was established by histologic examination of placentae. Zygosity was determined with sex of neonates, chorionicity, and DNA analysis of umbilical cord blood.Results:The frequency of dizygotic (DZ) twins was 71.0% (404/569 pairs) based on the opposite sex (238/404 [58.9%]) and DNA analyses (166/404 [41.1%]); that of monozygotic (MZ) twins was 29.0% (165/569), including monochorionic (MC) (72.1% [119/165]) and dichorionic (DC) twins (27.9% [46/165]), which was confirmed by DNA analyses. Among spontaneously conceived twins, the frequency of MZ twins was more than twice that of DZ twins. The risk of low birth weight was 1.8-fold higher among MZDC twins and 1.9-fold higher among MZMC twins than among DZDC twins (p< .05). Bronchopulmonary dysplasia occurred more frequently among MZMC twins than among DZDC twins (adjusted OR 8.42, 95% CI 1.82–39.08,p< .01). However, the frequencies of other neonatal morbidities were not significantly higher in the MZMC group than in the MZDC and DZDC groups. The perinatal mortality rate was 15 per 1000 total births in the DZDC twins, 20 per 1000 total births in the MZDC and 56 per 1000 total births in the MZMC (p< .01).Conclusions:Although monozygosity was shown to be a risk factor for perinatal death and accurate determination of zygosity plays a great role in the future consideration of organ transplantation and twin studies, the value of zygosity determination along with chorionicity in relation to overall neonatal morbidity was not definite.

Investigating SAPAP3 variants in the etiology of obsessive-compulsive disorder and trichotillomania in the South African white population

BACKGROUND

Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder characterized by repeated obsessions and compulsions. Trichotillomania (TTM), a psychiatric disorder characterized by repetitive hairpulling, is presently classified as an impulse control disorder, but has also been viewed as an obsessive-compulsive spectrum disorder. Both conditions are complex disorders, with evidence from family and twin studies indicating that their etiology includes a genetic component. Results from a recent knockout animal model suggest that SAP90/PSD95-associated protein 3 (SAPAP3) may be involved in the pathophysiology of both disorders.

METHODS

Seven polymorphic variants distributed across the gene encoding SAPAP3 were genotyped in South African white OCD (n = 172), TTM (n = 45), and control (n = 153) subjects. Single-locus and haplotype analyses were conducted to determine association between genetic variants and subjects with OCD, TTM, and controls.

RESULTS

Although single-locus analysis revealed a significant association between rs11583978 in SAPAP3 and TTM, this association was nonsignificant after correction for multiple testing. In the OCD group, a significant association was observed between earlier age at onset and the A-T-A-T (rs11583978-rs7541937-rs6662980-rs4652867) haplotype compared with the C-G-G-G haplotype.

CONCLUSIONS

This study generated preliminary evidence to link SAPAP3 variants to the development of earlier onset OCD. Future studies should concentrate on locating the susceptibility variant(s) by focusing on functional polymorphisms within SAPAP3.

Family-based genetic association study of DLGAP3 in Tourette Syndrome

Tourette syndrome (TS) is a childhood-onset neuropsychiatric disorder that is familial and highly heritable. Although genetic influences are thought to play a significant role in the development of TS, no definite TS susceptibility genes have been identified to date. TS is believed to be genetically related to both obsessive-compulsive disorder (OCD) and grooming disorders (GD) such as trichotillomania (TTM). SAP90/PSD95-associated protein 3 (SAPAP3/DLGAP3) is a post-synaptic scaffolding protein that is highly expressed in glutamatergic synapses in the striatum and has recently been investigated as a candidate gene in both OCD and GD studies. Given the shared familial relationship between TS, OCD and TTM, DLGAP3 was evaluated as a candidate TS susceptibility gene. In a family-based sample of 289 TS trios, 22 common single nucleotide polymorphisms (SNPs) in the DLGAP3 region were analyzed. Nominally significant associations were identified between TS and rs11264126 and two haplotypes containing rs11264126 and rs12141243. Secondary analyses demonstrated that these results cannot be explained by the presence of comorbid OCD or TTM in the sample. Although none of these results remained significant after correction for multiple hypothesis testing, DLGAP3 remains a promising candidate gene for TS.

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.

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.