My son is dx with autism spectrum disorder and also has significant anxiety and depression. The school he attends (not a UC) made it clear from the beginning that they do not give singles for those types of issues. They explained that it is their philosophy that these students, who are usually socially awkward, are poorly served by an isolated, single room and are better able to access college programming with a roommate. In addition, the dorm itself is usually chaotic enough that a single wouldn’t help that much. That’s what they told us.
In other words, at that college, the disability office believes that a person with a social disability not only does not need a single room, that person may be negatively affected by a single room. My son is fine - his roommate is very quiet and polite and no trouble - but this is an example of how a diagnosis can not be interpreted the way you think it needs to be interpreted.