The ICD's psychiatric disorder codes and criteria are used much more in countries outside of the US, such as Europe (although I think the DSM is used fairly frequently in the UK), Asia, etc. It is also used more in neuropsych when diagnosing conditions that are not in the DSM (eg., Lewy Body Dementia). Codes from the ICD are also used alot for billing purposes in neuropsychology since referral diagnosis is often not a psychiatric disorder, and thus not contained in the DSM. Criteria for diagnoses are often the same, but there are some differences.