Outdated websites since 30.12.2021

Excessive nail biting (biting one’s fingernails and/or the adjacent skin) and the compulsive pulling of one’s hair (trichotillomania) are classified as impulse control disorders. Although the direct health consequences of nail biting are rarely severe, apart from an occasional infection of the nail bed, the psychological consequences are often grave. Bitten nails are easily visible and often evoke disgust in other people. In the general population, nail biting is often equated with a nervous temperament and difficulty controlling impulsive behaviors. Because of the appearance of their hands, many sufferers are ashamed to shake other people’s hands. This may in turn prompt low self-esteem and social insecurity. At times, patients try to hide their fingernails, which paradoxically makes the disorder even more conspicuous.

Full, thick hair is commonly associated with health, whereas bald or balding areas on the head or a lack of eyelashes and eyebrows (typical features of trichotillomania) are often mistaken for a severe somatic illness, such as cancer. People with trichotillomania are frequently ashamed of their appearance and conceal bald patches with caps, scarves, or wigs. In many cases sufferers totally seclude themselves from their social environment, which substantially compromises their quality of life. Using the link below, you can download our manual describing a novel method designed to reduce excessive nail biting and/or hair pulling.

Preliminary Research Results on Decoupling

The feasibility and effectiveness of our approach for trichotillomania was established in a randomized-control study (Moritz & Rufer, 2010), which is summarized below.

Trichotillomania (TTM) is classified as an impulse control disorder characterized by the recurrent urge to pull out one’s own hair, resulting in noticeable hair loss. Cognitive behavioral therapy, involving habit-reversal training, currently represents the treatment of choice. A study by Moritz and Rufer (2010) assessed the feasibility and effectiveness of a novel technique called decoupling (DC). DC aims to attenuate TTM by having individuals perform movements that decouple the movements and behavioral elements involved in hair pulling (i.e., performing a different behavior than hair pulling when the urge arises; see manual). For the study, a total of 42 subjects with TTM were recruited via self-help forums. They completed an Internet survey, after which they were randomized either to DC or progressive muscle relaxation. After four weeks, participants were asked to fill out the same questionnaires and rate observed changes in symptoms (i.e., the effectiveness of the intervention).

The completion rate was high (91%). The DC group showed a significantly greater decline relative to progressive muscle relaxation on the Massachusetts General Hospital Hair Pulling Scale, which served as the primary outcome, indicating a medium to strong effect size. Declines on scales tapping symptoms of depression and obsessive-compulsive disorder were, however, comparable between the two groups. Despite methodological limitations and the need for replication, including a longer-term follow-up assessment and expert ratings of the intervention, the present study suggests that DC may prove beneficial to a substantial number of individuals with TTM.

Further information

For further information on trichotillomania, please visit the Trichotillomania Learning Center (TLC) at www.trich.org. The Trichotillomania Learning Center is a nonprofit organization based in the United States whose mission is to improve the quality of life of children, adolescents, and adults with trichotillomania and related body-focused repetitive behaviors such as skin picking. TLC works to raise awareness of these disorders, promote research and treatment advances, and provide information and support to sufferers and their families.


We would like to thank Jennifer Raikes, Executive Director of the Trichotillomania Learning Center, for her helpful comments on an earlier draft of the manual on decoupling.

Please donate
We provide the present as well as other self-help manuals at no cost. If you have benefited from the manual and/or would like to support our research, please consider making a donation. Donations of $20/20€ or more help us, for example, to create new self-help videos. You may donate online via this link, and you will receive an official receipt within a few days.