health

Developmental disabilities can be described as falling into one of several
types:

• Disabilities involving the brain, spinal cord, and nervous system.
  These developmental disabilities include mental retardation (Down
  syndrome, fragile X syndrome) and autism spectrum disorders.
  
• Disabilities related to hearing or vision loss.
• Disabilities related to metabolic disorders. Metabolism refers to
  the sum total of the chemical changes in the body that are needed
  to provide energy and repair or grow tissues. Metabolic disorders
  that affect children’s development include thyroid diseases and
  phenylketonuria.
  
• Disabilities related to degenerative disorders. Degenerative
  disorders are those in which a child appears normal at birth and
  reaches some developmental milestones but then starts to lose
  the abilities theyhave attained.

Developmental disabilities have been recognized for centuries even
though people did not always understand their causes. Before
the eighteenth century, people suffering from mental retardation
and other disabilities were often cared for by their families or
in religious institutions like monasteries. After the Industrial
Revolution in the nineteenth century, people with developmental
disabilities were more likely to be taken from their families in
childhood and placed in large asylums—some containing as many
as several thousand people. Some of these institutions
provided an elementary education as well as food, shelter,
and clothing, but most met only the basic needs of the children
and adults in their care. It was not until the 1960s that doctors
and teachers began to question the effectiveness of placing
people with disabilities in large institutions.
Between the 1960s and the 1990s, the United States and other
developed countries moved toward individualized education and
social support for people with developmental disabilities.
Instead of separating these persons from the wider community,
doctors and teachers now focus on each individual’s gifts and talents
as well as their needs, and try to place them in classroom and
work settings where they can interact with others. In 2000 the U.S.
Congress passed the Developmental Disabilities Assistance
and Bill of Rights Act, which funds four grant
programs to assist people with developmental disabilities and their
families.
There are still several challenges to teaching and treating or supporting
people with developmental disabilities. One is that these children
and adults are vulnerable to abuse by others. They also have a higher
than normal rate of mental health issues, not only because they are often
hurt or abused but also because they frequently become dependent on
drugs or alcohol. Third, people with developmental disabilities sometimes
behave in ways that are upsetting or dangerous to others, such as
hitting, screaming, kicking, being sexually inappropriate, stealing or
throwing objects, or injuring themselves. Treatment of people with
developmental disabilities often has to include medications or psychotherapy
to help them control problem behaviors.