Mild
IQ 52–69
Often presents as speech–language delay
Often not diagnosed until later age
Can develop social and communication skills
Some difficulty learning reading, writing, and math, but can learn up to about the 6th-grade level by late adolescence
Challenges making plans and managing money
Socially immature but can be expected to learn appropriate social skills
Some limitation of judgment and understanding of risk—more easily manipulated by others
Needs guidance and assistance in complex tasks (such as health care and legal decisions) and during times of unusual social or economic stress
Can usually achieve enough social and vocational skills for self-support
Moderate
IQ 36–51
Poor social awareness
Can profit from training in self-help
Can talk or learn to communicate
With support, can progress to elementary school level in schoolwork
May learn to travel alone in familiar places
Social judgment and understanding limited but can learn some social and occupational skills
May have successful friendships and romantic relationships
Cares for simple personal and household needs after extended guidance
Needs supervision and guidance managing money, scheduling, and all but simplest daily tasks
May achieve self-support by doing work in a supportive environment
Severe
IQ 20–35
Able to learn some self-help skills
Has limited speech skills
Can say a few words
Can talk or learn to communicate about simple, everyday events and learn simple health habits
Little understanding of written language, numbers, time, or money
Benefits from habit training
Usually successful relationships with family members and familiar others
Sometimes maladaptive behavior (including self-injury)
Can develop some useful self-protection skills in controlled environments
Requires support for most daily tasks but may contribute partially to self-care with a high level of supervision
Profound
IQ 19 or below
May need nursing support due to limited self-care skills and increased risk of associated health conditions
Extreme cognitive limitation
Often sensory and/or physical impairments
Limited understanding of speech or gestures; communicates mainly nonverbally
Enjoys company of well-known family and caretakers, but sensory and physical impairments often limit social activities
Often needs nursing support
May have very limited participation in self-care
