According to Centers for Disease Control and Preventions (CDC), developmental disabilities are a diverse group of severe chronic conditions that are due to mental and/or physical impairments. People with developmental disabilities have problems with major life activities such as language, mobility, learning, self-help, and independent living. Developmental disabilities begin anytime during development up to 22 years of age and usually last throughout a person's lifetime.
The term "developmental disabilities" is used most commonly to refer to disabilities affecting daily functioning in three or more of the following areas:
- capacity for independent living
- economic self-sufficiency
- receptive and expressive language
Frequently, people with mental retardation, cerebral palsy, autism spectrum disorder, various genetic and chromosomal disorders such as Down Syndrome and Fragile X Syndrome, and Fetal Alcohol Spectrum Disorder are described as having developmental disabilities. This use of the term is synonymous with the use of the term learning disability, intellectual disability and cognitive disability.
Developmental disabilities are usually classified as severe, profound, moderate or mild, as assessed by the individual's need for supports, which may be lifelong.
Some people with developmental disabilities exhibit challenging behavior. Common types of challenging behavior include self-injurious behavior (such as hitting, head butting, biting), aggressive behavior (such as hitting others, screaming, spitting, kicking), inappropriate sexual behavior, behavior directed at property (such as throwing objects and stealing) and stereotyped behaviors (such as repetitive rocking, echolalia or elective incontinence).
Challenging behavior in people with developmental disabilities may be caused by a number of factors, including biological (pain, medication, the need for sensory stimulation), social (boredom, seeking social interaction, the need for an element of control, lack of knowledge of community norms, insensitivity of staff and services to the person's wishes and needs), environmental (physical aspects such as noise and lighting, or gaining access to preferred objects or activities), psychological (lonely, devalued, labeled, disempowered, living up to people's negative expectations) or simply a means of communication. A lot of the time, challenging behavior is learned and brings rewards and it is very often possible to teach people new behaviors to achieve the same aims.
Experience and research suggests that what professionals call 'challenging behavior' is often a reaction to the challenging environments that those providing services create around people with developmental disabilities. "Challenging behavior" in this context is a method of communicating dissatisfaction with the failure of those providing services to focus on what kind of life makes most sense to the person, and is often the only recourse a developmentally disabled person has against unsatisfactory services or treatment and the lack of opportunities made available to the person.