RESUMO
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.
RESUMO
Epidemiological studies of excoriation disorder have reported different prevalence estimates for this condition, limiting our understanding of its public health impact. We performed a systematic review and meta-analysis to collate epidemiological studies of excoriation disorder. We aimed to estimate the pooled prevalence and the female-to-male ratio of excoriation disorder in the general population. We searched Embase, PsycInfo, and PubMed up to May 2020 and updated the PubMed search in October 2021. Studies which reported the frequency of excoriation disorder in a sample from the general population were included in our meta-analyses. We made no restrictions regarding the definition or assessment of excoriation disorder. Data were pooled through random-effects meta-analyses. Of the 677 records identified through database searches, 19 studies involving 38,038 participants met our inclusion criteria. Meta-analyses demonstrated that excoriation disorder has an overall prevalence of 3.45% (95% CI 2.55, 4.65%) and impacts women more than men (female-to-male OR = 1.45; 95% CI 1.15, 1.81, p = 0.001). These findings underscore the public health impact of excoriation disorder, which will hopefully motivate future research focused on advancing our understanding and management of this condition.
