I have read the paper “The relationship between sensory processing, childhood rituals and obsessive compulsive symptoms” by Reuven Dar*, Dennis T. Kahn and Ran Carmeli published in the Journal of Behavior Therapy and Experimental Psychiatry. The studies carried out could be improved but regardless, based on my own experience, I am not all surprised by the conclusions drawn. As a child I can remember being hypersensitive to certain sensory inputs. I was disgusted by a lot of tastes and textures. Sand between my toes would lead to a complete meltdown and glue on my hands was a pretty big deal. I could always feel things touching me, sometimes even when they apparently weren’t, and I was very bothered by it.
I can see how my fear of contamination may have been assisted by the fact that I could remember and chart very well what had touched me where; the feeling of being touched did not really leave me when the touch ceased, so I felt that I was somehow contaminated. I can also speculate about the effects of this beyond the fact that I developed various OC-type rituals and demanded a certain rigidity from my environment indicative of standard OCD (which is what the paper looks at). With regards to other disorders on the spectrum, being aware of every tiny sensation in and around my body could easily have been a starting point for hypochondriasis. Since many sensations were actually strong enough to be disturbing I assumed this meant there was something really wrong. This may also account for my persistent compulsive skin picking; without even looking at my skin I can feel where it is dry or clogged up and I have to get rid of those feelings. Finally, my disgust with food may have contributed to my sometimes sense that food is bad and that I am better off without it, which has resulted in periods of food intake restriction.
Sensory processing could account for a lot. This idea fits well with the fact that those with autism, who also often have sensory issues, may be diagnosed with comorbid OCD. What I do not see is how this could tie in to the other aspects of OCD such as intrusive thoughts.