(Victoria, BC, Canada)
No, I do not think it is 'real'. It is a vast over-simplification of neuroscience. There are no basic neuroscientists who believe that difficulties processing sensations cause these types of problems. By the way, sensory processing is actually called 'perception'. Perception is the process by which input into the brain (sensation) is transformed into meaningful information. Psychophysics is the study of sensory processes, and I have never seen any reference to perception or psychophysics in any discussion of sensory processing or sensory integration disorder. The problem is that sensory processing is an occupational therapy notion, and I'm afraid that occupational therapists receive very little training in sensation/perception/psychophysics, and little in neuroscience.
BTW, isn't 'sensory sensitivity' a redundancy? Is it possible to be sensitive to anything that is not sensory?!