The main parts of intellectual disability are problems with mental functioning and adaptive behavior. If you apply for a regional center under this category, you must show you have problems in both of these areas. You must know the features of intellectual disability. You must show the regional center or a judge which features you have. You must also show these features are caused by your mental impairments and not by something else like physical, learning, or psychiatric disabilities. Because of their mental impairments, people with intellectual disability generally have problems:

• learning academic skills like reading, writing, math, time, and money
• planning, strategizing, setting priorities, and adjusting to things that change
• remembering things
• understanding social cues
• communication (including nonverbal communication), carrying on a two-way conversation, and language
• controlling emotions and behaviors as well as other people their age
• appreciating risks in social situations, exercising good social judgment, and avoiding manipulation by others
• independently shopping for food, getting around in the community, organizing the home, eating healthy food, managing money, making health care and legal decisions, and using leisure time well
• working competitive jobs and having good work skills.^[1]DSM-5, Intellectual Disability, Table 1.

The case of Mason v. Office of Administrative Hearings decided if someone who applied for the regional center had a condition closely related to intellectual disability.^[2]89 Cal.App.4th 1119 (2001). The court decided that a condition “closely related” must be very similar to intellectual disability. It must have many of the same, or close to the same, factors needed to classify a person as having an intellectual disability.^[3]Mason at page 1129.

With Samantha C. v. State Dept. of Developmental Services, the court decided that problems with adaptive functioning alone were not enough to have a condition closely related to intellectual disability.^[4]185 Cal.App.4^th 1462 at 1486 (2010).

Courts and administrative law judges have talked about the Association of Regional Center Agencies’ Guidelines for Determining 5^th Category Eligibility for California Regional Centers (2002) in decisions.^[5]Samantha C. v. State Department of Developmental Services (2010) 185 Cal.App.4th 1462, 1477; Ronald F. v. Department of Developmental Services (2017) 8 Cal.App.5th 84, 95; Claimant v. Inland Regional … Continue reading We call this document as the “ARCA Guidelines.” The ARCA Guidelines are not law. They are not seen as official by the Legislature, any court or judge, or the Department of Developmental Disabilities.

For cognitive functioning, the ARCA Guidelines say a condition closely related to intellectual disability means IQ scores in the low borderline range (70-74). The ARCA Guidelines say the condition would affect your ability to solve problems with insight, to adapt to new situations, to think abstractly, and to benefit from the experience.^[6]See Title 17, Cal. Code of Regs., section 54002. The ARCA Guidelines say your condition must be stable over time. This means your condition does not change much. The ARCA Guidelines say people with intellectual disabilities do not show a major difference between their cognitive skills. This means you would not show major problems with one type of cognitive skill, like talking, but strengths in another type of cognitive skill, like performance. Judges have found that persons with intellectual disability do not vary much in their cognitive skills, but have major problems across most areas of mental functioning.^[7]Claimant v. Inland Regional Center (2021) OAH Case No. 2018061194.1, at pages 44-46.

For adaptive behavior problems, the ARCA Guidelines refer mainly to functioning in the same areas as substantial disability (communication, learning, self-care, mobility, self-direction, independent living, and economic self-sufficiency). They say to look at your scores on adaptive behavior tests. They also say people with intellectual disabilities have adaptive behavior problems that do not come from physical or mental health conditions, socio-cultural problems, poor motivation, substance abuse, or limited experience.^[8]Section 4512(l)(1). Supplement E to this manual has a list of features of intellectual disability. Some of these have been recognized as features of intellectual disability by regional centers, ARCA Guidelines, administrative law judges, and courts. But many have not. Whatever features of intellectual disability you have, they must be caused by your intellectual impairments and not by some other disability or condition.