The U.S. Supreme Court recently issued a unanimous opinion that makes it more difficult for employees to prevail in work-related claims under the Americans With Disabilities Act (ADA). In the case of Toyota Motor Manufacturing, Kentucky, Inc. v. Williams (1), the Court clarified the legal principles governing the determination of disability under the statute. In doing so, it furthered a trend in the Court toward a more conservative reading of the ADA. The Court's decision will make it more difficult for people with mental illnesses to successfully pursue claims under the ADA.

The ADA prohibits discrimination in the workplace on the basis of disability (2). Although employees who have mental disabilities may fare less well than those who have physical disabilities in pursuing claims under the ADA (3,4), the statute has been an important source of new rights for people with disabilities. The U.S. Supreme Court has heard a number of cases that have applied the ADA and has issued rulings that appear to expand the rights of people with mental disabilities, particularly those who have been inappropriately institutionalized (5,6).

At the same time, however, the Court has grown increasingly cautious in its application of the ADA, principally through narrowing the definition of disability. For example, in 1999 the Court ruled that a person's disability status must be assessed only after the person has taken corrective steps to address the impact of the disability. This ruling has resulted in judgments that some people with serious illnesses, including depression, are not disabled, because they have taken corrective steps to address the illness, such as taking medication (7).

The Toyota Motor case continues this conservative trend. In this case an employee who worked at an automobile manufacturing plant developed carpal tunnel syndrome. She was advised by her physician not to lift weights of more than 20 pounds and to avoid certain repetitive motions. For two years, the employee was assigned modified job duties. However, she grew unhappy with her duties and eventually brought a workers' compensation claim against her employer and an initial claim under the ADA, both of which eventually were settled.

The employee received another assignment in the defendant's quality control inspection operations and soon thereafter began experiencing pain associated with the effects of carpal tunnel syndrome. She was terminated for poor attendance and then lodged a claim of discrimination due to disability with the Equal Employment Opportunity Commission (EEOC). The EEOC authorized the employee to pursue her claim in court, and she brought a federal lawsuit alleging that the defendant had violated the ADA and other laws by failing to reasonably accommodate her disability.

To prevail in an ADA claim, an employee must have a disability. The ADA defines "disability" as a physical or mental impairment that substantially limits one or more major life activities (8). Carpal tunnel syndrome is considered to be an impairment under the ADA. However, to qualify as being disabled under the ADA, an employee with carpal tunnel syndrome or any other mental or physical impairment must also demonstrate that the impairment creates a substantial limitation in a major life activity.

The ADA itself does not delineate "major life activities." The EEOC has defined such activities in regulations, although whether it had the authority to do so has not been decided by the Supreme Court. The regulations define major life activities as "caring for oneself, performing manual tasks, walking, seeing, hearing, speaking, breathing, learning, and working" (9). In addition, the EEOC's interpretive guidelines, which emphasize that this list is not exhaustive, further define major life activities as "basic activities that the average person in the general population can perform with little or no difficulty" (10). In addition, courts have ruled that other activities can be considered major life activities under the ADA—for example, reproduction (11) and engaging in interpersonal relationships (12).

The employee in the Toyota Motor case alleged that her carpal tunnel syndrome substantially limited the major life activities of performing manual tasks, housework, gardening, playing with her children, lifting, and working. However, the district court ruled for the employer, because the employee had argued that she could perform other tasks at work—for example, painting—without difficulty. The district court also concluded that housework, gardening, and child care were not major life activities, and on appeal the employee abandoned her argument that they were.

The U.S. Court of Appeals reversed the district court's decision and ruled for the employee, concluding that she had met her burden of showing that she was substantially limited in performing a class of manual activities related to her tasks at work. The appeals court did not reach the question of whether those limitations extended to the major life activities of working or lifting, because it had ruled for the employee on the major life activity of performing manual tasks.

The U.S. Supreme Court then unanimously reversed the decision of the appeals court. The Court defined the issue as what a plaintiff must demonstrate to establish a substantial limitation in the specific major life activity of performing manual tasks. Because the major life activity in question was the performance of manual tasks, the employee had to show that the impairment "prevents or restricts the individual from doing activities that are of central importance to most people's daily lives. The impairment's impact must also be permanent or long-term."

The Supreme Court said that the court of appeals had erred in focusing its analysis on the impact of carpal tunnel syndrome on the employee's ability to perform work-related tasks. The Court thought this too narrow a focus, saying that "the central inquiry must be whether the claimant is unable to perform the variety of tasks central to most people's daily lives, not whether the claimant is unable to perform the tasks associated with her specific job." Therefore, the court of appeals should have focused on, rather than disregarded, the fact that the employee could take care of her personal hygiene, carry out household chores, and bathe and brush her teeth. Because these types of activities are central to the lives of most people, the Court concluded that they should be the focus of an analysis as to whether an impairment substantially limits the person's ability to participate in the major life activity of performing manual tasks.

In reaching its conclusion, the Court relied on a number of factors of increasing importance in its ADA analyses. First, it emphasized that the ADA had to be "interpreted strictly" to ensure that the number of people who qualify as being disabled is restricted. The Court referred, as it has done in other cases, to a statement that Congress made when it enacted the ADA that about 43 million Americans had a disability. According to the Court, a failure to strictly interpret which persons had a disability would vastly inflate the number of Americans with a disability beyond the figure noted by Congress.

In addition, the Court emphasized the importance of an individualized assessment in the question of disability. According to the Court, it is not enough to assume that all impairments create disability. In illustrating this point, the Court talked about the range of symptoms experienced by people with carpal tunnel syndrome. The notion of individualized assessment is integral to the ADA and applies to people with mental illnesses as well. For example, a person diagnosed as having schizophrenia is considered to have a disability under the ADA only if the mental illness substantially limits a major life activity for that person. Diagnosis alone does not establish disability under the statute.

Finally, and perhaps most important for future analyses, the Court noted the "conceptual difficulties inherent in the argument" that work is a major life activity. This was not the first time the Court had expressed such concerns (13), and it reflects an increasingly cautious approach to interpretation and application of the ADA. If "work" is a major life activity, then an individual may demonstrate that he or she has a disability by focusing on substantial limitations on tasks associated with work. In fact, some have argued that it is counterintuitive not to consider work a major life activity under the ADA (14).

However, the Supreme Court appears to be moving toward a conclusion that work is not considered a major life activity under the ADA, a conclusion that would create further difficulties for employees who attempt to bring disability claims under the statute. Such a ruling would mean that the effect of an impairment, mental or physical, on a person's ability to undertake work would no longer be the primary issue in any employment claim brought under the ADA. Rather, the inquiry would be whether the person was able to perform the types of tasks discussed by the Court in Toyota Motor, such as bathing, personal hygiene, and household chores. Such a focus would suggest that a person must show a very high level of general impairment before qualifying as disabled under the ADA.

This focus may have a particular effect on people with mental impairments. For example, a person with a mental illness might ask for an accommodation at work because of sensitivity to noise or light or some other stimulus. At the same time, that person may be perfectly capable of performing the activities of daily living that the Supreme Court says should be the focus of an inquiry. A person in this situation might not meet the definition of disability under the ADA despite the presence of a serious mental illness. As a result, the issue of reasonable accommodation will not be reached, because the person does not meet the threshold requirement of having a disability and so is not covered by the ADA.

In short, the Toyota Motor case further narrows the applicability of the ADA by creating another barrier for plaintiffs to overcome in demonstrating that they have a disability. This cautious reading of the ADA by the Court became evident first with its rulings, noted above, that an assessment of disability had to consider any corrective or ameliorative steps that had been taken by the individual.

The Toyota Motor case will push the inquiry in employment cases away from the workplace and toward ordinary living situations and may result over time in a narrowing of the applicability of the ADA to persons with the most severe disabilities. This result appears to run counter to the spirit of the ADA, which invites a broad reading of "disability" to enable people with disabilities to engage in employment and other activities that are often denied them. However, the Supreme Court is increasingly interpreting the ADA narrowly, and the accumulating impact of its decisions might be the creation of new barriers for at least some people with mental and physical disabilities.

Mr. Petrila is chair and professor in the department of mental health law and policy of the Louis de la Parte Florida Mental Health Institute at the University of South Florida, 13301 Bruce B. Downs Boulevard, Tampa, Florida 33612 (petrila@mirage.fmhi.usf.edu);. Paul S. Appelbaum, M.D., is editor of this column.