order, record autism spectrum disorder associated with (name of condition, disorder, or
factor) (e.g., autism spectrum disorder associated with Rett syndrome). Severity should be
recorded as level of support needed for ea ch of the two psychopa thological domains in
Table 2 (e.g., “requiring very substantial support for deficits  in social communication and
requiring substantial support fo r restricted, repetitive behaviors”). Specification of “with
accompanying intellectual impairment” or “without accompanying intellectual impair-
ment” should be recorded next. Language im pairment specification should be recorded
thereafter. If there is accompan ying language impairment, the current level of verbal func-
tioning should be recorded (e.g., “with accompanying language impairment—no intelligi-
ble speech” or “with accompanying language impairment—phrase speech”). If catatonia is
present, record separately “catatonia asso ciated with autism spectrum disorder.”
Specifiers
The severity specifiers (see Table 2) may be used to describe succinctly the current symp-
tomatology (which might fall below level 1), with  the recognition that severity may vary by
context and fluctuate over time. Severity of social communication difficulties and re-
stricted, repetitive behaviors sh ould be separately rated. The descriptive severity categories
should not be used to determine eligibility fo r and provision of services; these can only be
developed at an individual level and through di scussion of personal priorities and targets.
Regarding the specifier “with or without ac companying intellectual impairment,” un-
derstanding the (often uneven) intellectual prof ile of a child or adult with autism spectrum
disorder is necessary for interpre ting diagnostic features. Separate estimates of verbal and
nonverbal skill are necessary (e.g., using untimed nonverbal tests to assess potential
strengths in individuals with limited language).