The Social Security Administration, per the court case of Brock v. Astrue, has issued a ruling requiring a vocational expert to testify in hearings which involve an application for Social Security Disability, based on a "severe" mental impairment. This term "severe" mental impairment can include many diagnoses, such as Post-traumatic stress disorder (PTSD); bi-polar disorder and major depressive disorder.
The reasoning of the Court is that if a claimant seeking Social Security Disability benefits suffers from a severe mental impairment, only a vocational expert can ascertain whether the individual has the functional capacity to perform jobs which may exist in significant numbers in the national economy. Specifically, mental impairment can impact an individual claimant's capacity to function at work. For example, although such individual may be physically capable to work, a mental disability often impacts the ability to concentrate; focus; follow instructions and properly interact with co-workers or the public, is vital evidence as to whether someone is disabled. This is vital information for a Social Security Judge to understand in making a ruling on a case for Social Security Disability