Psychiatric conditions and touch

Abstract

Touch is an understudied sensory modality that has a significant neuroregulatory impact on social and emotional behavior relevant to psychiatric conditions. In particular, the sense of touch has a profound impact on early social development and bonding which makes it particularly relevant for neurodevelopmental disorders such as autism spectrum disorder (ASD). This chapter reviews behavioral and neural studies of touch in two categories of psychiatric diagnosis: ASD and obsessive compulsive (OCD) and related disorders. In ASD, altered tactile perception seems to be heavily weighted toward affective, rather than discriminative touch, and relates significantly to core symptoms including social deficits and repetitive behaviors. In OCD and related disorders, body-focused repetitive behaviors are significant and debilitating clinical symptoms that often involve affective dysfunction of the somatosensory system, including diminished nociception and/or altered reward response to tactile stimuli. Animal models suggest the involvement of serotonergic, dopaminergic, and oxytocin neurotransmitters/neuropeptides and neuroimaging studies implicate the interface of sensory systems with networks for affect and arousal in both classes of psychiatric conditions, but much more research is needed to clarify the role of touch in these clinical conditions. In addition, our understanding of other psychiatric conditions such as psychotic disorders and mood disorders would benefit substantially from more research on the role of touch in their development and clinical presentation.