Anxiety, depression and obsessive–compulsive disorder are more frequently encountered in people with<unk> .<unk>  has a high overlap with post traumatic stress disorder, and some cases of<unk>  may be triggered by stress. Another school of thought emphasizes hair pulling as addictive or negatively reinforcing, as it is associated with rising tension beforehand and relief afterward. A neurocognitive model — the notion that the basal ganglia play a role in habit formation and that the frontal lobes are critical for normally suppressing or inhibiting such habits — sees<unk>  as a habit disorder. Abnormalities in the caudate nucleus are noted in OCD, but there is no evidence to support that these abnormalities can also be linked to<unk> . One study has shown that individuals with<unk>  have decreased cerebellar volume. These findings suggest some differences between OCD and<unk> . There is a lack of structural MRI studies on<unk> . In several MRI studies that have been conducted, it has been found that people with<unk>  have more gray matter in their brains than those who do not suffer from the disorder. It is likely that multiple genes confer vulnerability to<unk> . One study identified mutations in the SLITRK1 gene.
Trichotillomania
Alopecia areata
Koilonychia
Loose anagen syndrome
Onychotillomania
Trichostasis spinulosa
Tinea imbricata
Necrospermia