Soft Touch Training for patients with skin-picking disorder

Skin-picking disorder (SPD) is a common mental disorder. SPD patients cannot stop picking their skin. This causes cuts, bleeding and/or bruising. A previous brain imaging study indicated that female SPD patients have a reduced sensitivity of pleasant touch compared to healthy controls. Therefore, the planned project aims at improving emotional and neural responses to soft touch of the skin. Female patients with SPD will be randomly assigned to either a Soft Touch Training (STT) or Progressive Muscle Relaxation (PMR: guided tensing and relaxing of selected muscle regions). Prior to the training (duration: 4 weeks), a standardized tactile stimulation procedure (slow/ fast brushing of the forearm) will be used to compare emotional and neural responses between SPD patients and healthy controls. After STT or PMR, the patients will undergo a second MRI testing with the same brushing design (slow/fast). It is predicted that STT will reduce skin-picking severity and will lead to altered neural activity and connectivity during caressing (soft brushing).

Skin-picking disorder (SPD) is a common mental disorder in the general population. The predominant symptom involves excessive picking (scratching, rubbing) of one's skin, resulting in skin lesions and distress as well as impairment in important areas of functioning. Most patients experience the picking as pleasant, which is surprising since the excessive manipulation of the skin causes tissue damage (wounds) which would generally be experienced as unpleasant. The symptoms of SPD described here point to possible dysfunctions in the processing of touch. Previous research has indicated that individuals with SPD may exhibit altered processing of 'affective touch' (gentle/slow touch: caressing). The research questions guiding this project with functional magnetic resonance imaging (fMRI) were as follows: (1) Do patients with SPD exhibit altered sensitivity and brain activity to affective touch compared to healthy controls? (2) Can a newly developed training, involving guided soft brushing of selected body regions, effectively reduce skin-picking symptoms and normalize brain activity during affective touch? The training consisted of an app-guided practice that provided auditory instructions for self-touching selected skin regions using a soft brush. Participants practiced daily for approximately 15 minutes over four weeks. As a control intervention, participants engaged in muscle relaxation. The main findings of the project were as follows: (1) Patients with SPD exhibited heightened sensitivity (hyperresponsivity) to affective touch compared to healthy controls, as indicated by both self-reports and fMRI data (increased activity in frontal and parietal brain regions involved in attentional control and integration of somatosensory information. (2) The training reduced both self-reported symptom severity and hyperactivation in brain regions concerned with touch processing and integration of somatosensory information. The developed training method holds promise for easy implementation in clinical practice (as an additional component of psychotherapy).