I was tested for autism and it came negative- what is the other disease that is similar?

Depends: Without knowing the age of the individual tested and the name of the test used it is hard to say. " autism tests" assess the presence or absence of certain skills and behaviors. These include language, social interaction, sensory issues and sterotypical movements. At younger ages autism spectrum disorders may appear similar to other neurodevelopmental disordeers. Ask provider for clarification.

Info processing prob: People with autism have problems with the way they process information. Plenty of people have information processng problems -sometimes severe , but do not meet the criteria for Autism, that just means your functional behavor does not meet the cut off-that is actually good news . What other "diagnosis" yu might have would depend on the specific symptoms or difficulties you are having .