Shared and unique neural mechanisms underlying pediatric trichotillomania and obsessive compulsive disorder.

BACKGROUND: Little is known about the neural underpinnings of pediatric trichotillomania (TTM). We examined error-related negativity (ERN)-amplitude and theta-EEG power differences among youth with TTM, OCD, and healthy controls (HC). METHODS: Forty channel EEG was recorded from 63 pediatric participants (22 with TTM, 22 with OCD, and 19 HC) during the Eriksen Flanker Task. EEG data from inhibitory control were used to derive estimates of ERN amplitude and event-related spectral power associated with motor inhibition. RESULTS: TTM and HC were similar in brain activity patterns in frontal and central regions and TTM and OCD were similar in the parietal region. Frontal ERN-amplitude was significantly larger in OCD relative to TTM and HC, who did not differ from each other. The TTM group had higher theta power compared to OCD in frontal and central regions, and higher theta than both comparison groups in right motor cortex and superior parietal regions. Within TTM, flanker task performance was correlated with EEG activity in frontal, central, and motor cortices whereas global functioning and impairment were associated with EEG power in bilateral motor and parietal cortices. CONCLUSIONS: Findings are discussed in terms of shared and unique neural mechanisms in TTM and OCD and treatment implications.