Invisible (or hidden) disabilities are usually defined as those that don’t manifest in ways that are immediately obvious to others.
This is a loosely-defined blanket category that may include any number of disabilities, impairments, or medical conditions. This can include chronic pain or fatigue; cognitive or learning disabilities or differences; head or brain injuries; hearing disabilities or impairments; vision disabilities or impairments; and much more.
The impact or the validity of a disability is not based on the ability of others to perceive it or to know how to perceive it. Many people with invisible disabilities fall under the coverage of laws like the Americans with Disabilities Act (ADA), by having a “physical or mental impairment that substantially limits one or more major life activities.” However, because their condition is not obvious, people with these disabilities might face different types of discrimination that others do not, like being accused of imagining their symptoms or not being believed.
The Invisible Disabilities Association (IDA) defines the term succinctly:
In simple terms, an invisible disability is a physical, mental or neurological condition that is not visible from the outside, yet can limit or challenge a person’s movements, senses, or activities. Unfortunately, the very fact that these symptoms are invisible can lead to misunderstandings, false perceptions, and judgments.
IDA also uses the term in a sentence: “People are parking in an accessible parking space with a placard, but they look fine. I wonder if that driver has an invisible disability.”
Disabled-World.com puts it this way:
Invisible Disability, or hidden disability, is an umbrella term that captures a whole spectrum of hidden disabilities or challenges that are primarily neurological in nature. Invisible disability, or hidden disability, are defined as disabilities that are not immediately apparent. Some people with visual or auditory disabilities who do not wear glasses or hearing aids, or discreet hearing aids, may not be obviously disabled. Some people who have vision loss may wear contacts. A sitting disability is another category of invisible impairments; sitting problems are usually caused by chronic back pain. Those with joint problems or chronic pain may not use mobility aids on some days, or at all. Although the disability creates a challenge for the person who has it, the reality of the disability can be difficult for others to recognize or acknowledge. Others may not understand the cause of the problem, if they cannot see evidence of it in a visible way.
Statistics and measurements on disability always vary according to the definitions and reporting methods used. Statistics for this category may be even more likely to fluctuate than other disability types because there are so many illnesses, conditions, and disabilities that can have a major impact on a person’s life activities but that aren’t visible or apparent, at least immediately.
About 25% of U.S. adults have a disability, and most invisible disability metrics in the U.S. say that roughly as high as 20% (or more) of Americans have an invisible disability. Further, most people who have a disability don’t use obvious assistive technology like a wheelchair or cane, and the vast majority of people with a serious condition or illness have a hidden one.
It’s more likely, then, to meet someone with a hidden disability than an obvious one.