Body focused repetitive behavior disorders: Significance of family history

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.

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.

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.

Automatic and focused hair pulling in trichotillomania: Valid and useful subtypes?

Prior work suggested that trichotillomania may have four subtypes based on the extent to which pulling is automatic or focused in nature. 238 adults with trichotillomania undertook clinical and cognitive assessments and were assigned into four subtypes based on k-means clustering of Milwaukee Inventory for Subtypes of Trichotillomania-Adult Version (MIST-A) scores. We examined whether a cluster solution was apparent using conventional metrics. Based on prior literature, we then force-fitted a four subtype model (low-low, low-high, high-low, high-high). Subtypes were compared and validity of the MIST-A subtyping approach was evaluated. A cluster solution did not converge based on conventional metrics. Following force-fitting, subtypes did not differ on demographic variables, age at symptom onset, nor duration of illness. The high-focused high-automatic subtype had worse symptom severity than other subtypes. Co-morbid depression was more common in the low-focused low-automatic and high-focused low-automatic subtypes. This study suggests that MIST-A subtypes may not be valid or clinically useful based on several issues. First, k-means models indicated that the MIST-A data did not generate any cluster solutions. Second, when a forced cluster solution was fitted, the subtypes did not differ on the vast majority of measures. Third, force-fitting four subtypes yielded findings that were logically inconsistent (e.g. worse quality of life in one group, but higher rates of comorbid anxiety/depression in others). Overall, we suggest that both focused and automatic pulling may characterize the same pulling episode, or certainly the same person across episodes. Thus they may be clinically relevant variables, but not forming coherent subtypes.

Evaluating the role of Approach-Avoidance Training on action-tendencies in individuals with skin-picking disorder: A preliminary randomized experiment

BACKGROUND AND AIMS

Pathological skin-picking (PSP) or excoriation disorder is a destructive behavior that affects 1-2% of the general population. The purpose of this pilot study was to evaluate the effect of a computerized behavior modification task on action-tendencies (i.e., approach or avoidance) in adults with PSP. We aimed to modify these action-tendencies by having participants with PSP complete the Approach-Avoidance Training (AAT) task, using a joystick to simulate an approach (=pull) or avoidance (=push) response.

METHOD

Forty-five participants diagnosed with PSP were randomized to one of three training conditions: (1) Avoidance Training (AvT; n = 15), (2) Approach Training (ApT; n = 15), or (3) Placebo Training (PT; n = 15). We hypothesized that after training, those in the AvT would have the greatest reduction in behavioral approach (i.e., their overall reaction time [RT] to approach pictures of irregular skin stimuli).

RESULTS

Results of the pre-training assessment task revealed a positive correlation between behavioral approach to irregular skin stimuli and skin-picking severity as assessed by the Skin Picking Scale-Revised (SPS-R). After training, a lower behavioral approach and urges to pick were found in the AvT and PT groups, while those in the ApT reported higher behavioral approach and urges to pick. At two-week follow-up, no significant changes on the SPS-R were reported between groups.

DISCUSSION

Our preliminary data suggest that the AAT is a promising avenue of research to develop as a cognitive intervention to address an excessive behavioral approach tendency that characterizes skin-picking problems.

Habit reversal therapy in the management of body focused repetitive behavior disorders

Body-focused repetitive behavior disorders are a group of disorders characterized by repetitive actions that include skin picking, hair pulling, nail biting, and other compulsions. These disorders can range from a common habit to a pathological disorder, that negatively impacts the psychiatric health and social well-being of an individual. Diagnosis can be made clinically, and monitored using different scales and assessments. Various treatments have been tried with differing successes. There are currently no first line curative medications for these disorders, but cognitive behavioral therapy has seen the most success in treatment. Specifically habit reversal therapy has shown the most promise in reducing the repetitive behaviors and symptoms seen in these disorders. Habit reversal therapy has also seen success through augmentation with additional therapies such as mindfulness, or treatment with a selective serotonin reuptake inhibitor in a patient with comorbid obsessive compulsive disorder. This paper aims to explore the efficacy of different treatment modalities specifically the effectiveness and approach of habit reversal therapy.

Family history of substance use disorders: Significance for mental health in young adults who gamble

BACKGROUND

Although family history of psychiatric disorders has often been considered potentially useful in understanding clinical presentations in patients, it is less clear what a positive family history means for people who gamble in the general community. We sought to understand the clinical and cognitive impact of having a first-degree relative with a substance use disorder (SUD) in a sample of non-treatment seeking young adults.

METHODS

576 participants (aged 18-29 years) who gambled at least five times in the preceding year undertook clinical and neurocognitive evaluations. Those with a first-degree relative with a SUD were compared to those without on a number of demographic, clinical and cognitive measures. We used Partial Least Squares (PLS) regression to identify which variables (if any) were significantly associated with family history of SUDs, controlling for the influence of other variables on each other.

RESULTS

180 (31.3%) participants had a first-degree family member with a SUD. In terms of clinical variables, family history of SUD was significantly associated with higher rates of substance use (alcohol, nicotine), higher rates of problem gambling, and higher occurrence of mental health disorders. Family history of SUD was also associated with more set-shifting problems (plus higher rates of obsessive-compulsive tendencies), lower quality of decision-making, and more spatial working memory errors.

CONCLUSIONS

These results indicate that gamblers with a first-degree family member with a SUD may have a unique clinical and cognition presentation. Understanding these differences may be relevant to developing more individualized treatment approaches for disordered gambling. Compulsivity may be important as a proxy of vulnerability towards addiction.

Neurocognitive Findings in Onychophagia (Pathological Nail Biting)

A notable number of people struggle to control the desire to bite their nails, resulting in impairment and distress. Understanding this behavior and the inability to control it has received little research attention. One possible mechanism to understand nail biting is through the use of neurocognitive assessments. Neurocognitive assessments of pathological nail biting, however, are lacking. This analysis assesses the clinical presentation and neurocognitive profile of adults with nail biting relative to participants without nail biting. A total of 87 participants (aged 18-29 years) were recruited for a study on nail biting in young adults. Participants completed diagnostic, self-report, and neurocognitive measures which assessed two cognitive domains - motor impulsivity and cognitive flexibility. In the sample, 34 participants reported current nail biting. The nail biting group showed no significant differences in impulsivity or cognitive flexibility compared to the healthy controls. The lack of association between nail biting and cognitive deficits suggests that perhaps identifying meaningful subtypes of nail biting that reflect distinct pathology from normal grooming behavior may be important.