SPD is the single worst aspect of my existence, hands down. It's made me pretty agoraphobic, thanks to the times I've started blacking out during sensory overload. It was worse when I was younger and couldn't understand what was happening. These days, it's more of a drain than a source of panic, which has helped quite a bit. Socially, and apart from the agoraphobia, it affects my ability to focus in chaotic environments (which, from my point of view, is most environments). Conversations can become impossible and eye-contact is frustrating. If I reach sensory overload it's difficult to understand people and process my surroundings, like trying to read rolling text that's moving too fast. But the effects of SPD is something that I've seen vary from source to source. Some, especially those that advocate it as an independent diagnosis, tend to blame SPD for a whole host of neurological and physical symptoms, from joint hypermobility and atypical drug reactions to social impairments and executive dysfunction. Others, more straight-forward, limit it to problems with sensory integration. In the former case, there seems to be a very fine line between ASD and SPD, but I can't really work out where it's drawn.
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I have not the kind affections of a pigeon. - Ralph Waldo Emerson