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.

Tourette and tic disorders in ICD-11: standing at the diagnostic crossroads

This article reflects discussion by the WHO ICD-11 Working Group on the Classification of Obsessive-Compulsive and Related Disorders. After reviewing the historical classification of tic disorders, this article discusses their placement in ICD-11. Existing problems with diagnostic labels and criteria, appropriate placement of the tic disorders category within the ICD-11 system, and pragmatic factors affecting classification are reviewed. The article ends with recommendations to (a) maintain consistency with the DSM-5 diagnostic labels for tic disorders, (b) add a minimum duration guideline for a provisional tic disorder diagnosis, (c) remove the multiple motor tic guideline for the diagnosis of Tourette disorder, and (d) co-parent the tic disorder diagnoses in the disorders of the nervous system and the mental and behavioral disorders categories, with secondary co-parenting in the obsessive-compulsive and related disorders and neurodevelopmental disorders sections.