Is an individual disabled within the meaning of the Social Security Act?

An individual is disabled within the meaning of the Social Security Act when she "is unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which ... can be expected to last for a continuous period of not less than twelve months." 42 U.S.C. Sec. 1382c(a)(3)(A); see also 20 C.F.R. Sec. 416.909. The claimant bears the burden of establishing a prima facie case of disability. Drouin v. Sullivan, 966 F.2d 1255, 1257 (9th Cir.1992). This burden requires the claimant to make out a case both that she has an impairment listed in the regulations, and that she has met the duration requirement. See 20 C.F.R. Sec. 416.920(d).