Trichotillomania (TTM) is the recurrent pulling out of one’s hair resulting in hair loss. Pulling causes clinically significant distress or functional impairment, is accompanied by repeated efforts to stop, and is not due to another mental disorder or a general medical condition.
- Hair pulling can occur in any region of the body, but the most common sites are the scalp, eyelashes, and eyebrows. Other relatively common sites include the axilla, face, and pubic area. Sites may vary over time.
- Pulling can occur in brief episodes throughout the day or in sustained bouts.
- Automatic pulling is outside the patient’s awareness.
- Focused pulling is in response to identifiable affective triggers.
- Some patients experience tension immediately before pulling or when attempting to resist the behavior, whereas others experience pleasure or relief when pulling.
- Patients may search for and pull hairs with specific qualities (e.g., thick hairs or short hairs).
- More than half of patients engage in a “ritual” with the hair before discarding it.
- TTM does not include habitual hair twirling.
- Typical onset in childhood or adolescence: often coincides with the onset of puberty
- In childhood, girls and boys are equally affected.
- In adulthood, the ratio of affected females to males is 10:1.
1–3% lifetime prevalence
TTM is more common in individuals with obsessive-compulsive disorder (OCD) and in their 1st-degree relatives.
- A study of >5,400 female twins suggests that the heritability of TTM is ~30%, and that it has substantial genetic overlap with excoriation disorder (ExD), also known as skin picking disorder. Approximately 1/3 of genetic risk for TTM is shared with other obsessive-compulsive and related disorders.
- No specific genes implicated, although animal models of TTM exist
Commonly Associated Conditions
- Trichophagia (ingesting hair), which can lead to trichobezoar. It is estimated that between 5% and 18% of patients with TTM ingest their hair.
- Psychiatric comorbidity is common (seen in 1/3 to 2/3 of children with TTM) and includes autism, pervasive developmental disorder (PDD), anxiety, attention deficit, substance use, and eating disorders.
- Patients may also engage in nail-biting, skin-picking, or other pathologic grooming behaviors.
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