The National Institutes of Health defines intellectual and developmental disabilities as impairments that usually begin at or shortly after birth and can affect the trajectory of physical, intellectual, and emotional development throughout one’s life. A recent analysis of federal data on children ages 3 to 17 suggests that there will be a trend toward more adults living with some form of IDD in the coming years.
From 2015 to 2017, 17.8% of children were diagnosed with some kind of disability, including attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder, intellectual disability, and cerebral palsy. This is 1.6 percentage points higher than in 2009 to 2011, when 16.2% of children were diagnosed with some kind of disability (Zablotsky, B., et al, Pediatrics, Vol. 144, No. 4, 2019). Although the study did not examine underlying causes, the overall increase, which is largely due to a higher proportion of children diagnosed with autism and ADHD, may reflect greater awareness and improved access to healthcare, the authors wrote. Research findings vary, but broadly speaking, one-third to one-half of children and adults with IDD also meet criteria for at least one psychiatric disorder, says Hartley, an APA specialist in Division 33 (intellectual and developmental disabilities/autism spectrum disorders) and an associate professor of human development and family studies at the University of Wisconsin-Madison, who works in research and other work with adolescents and adults with intellectual and developmental disabilities. Hartley said patients with intellectual and developmental disabilities may also be dealing with one or more co-occurring behavioral challenges, such as repetitive behaviors or inattention. “We often see a complex profile of mental health and behavioral problems,” Hartley said.
Recent findings also suggest that there is an overlap between disorders and gender identity: One study looking at five datasets totaling more than 600,000 people found that people who identify as transgender or gender diverse are three to six times more likely to be diagnosed with autism than cisgender people (Warrier, V., et al., Nature Communications, Vol. 11, 2020).
There are a variety of tools available for screening and assessing adults for intellectual disability, including the Reese’s Maladaptive Behavior Screen (to identify problem behaviors), the Psychiatric Assessment Schedule for Adults with Developmental Disabilities (PAS-ADD) checklist and the Achenbach Empirical Assessment System for Adults with Developmental Disabilities (ASEBA), but more education needs to be done so psychologists, social workers, case managers and other frontline workers who work with these adults are aware of the tools, Hartley said.
Hartley said another thing to consider in identifying mental health issues is that some IDDs can have different symptoms than those defined in the traditional Diagnostic and Statistical Manual of Mental Disorders (DSM). A useful guide, the Diagnostic Manual of Mental Disorders – Intellectual Disabilities, can educate clinicians about some of those symptoms, she said.
For example, adults with Down syndrome may not verbalize thoughts that signal depression, Hartley says. Instead, they may become more irritable, she says. They may argue more frequently with coworkers or be unwilling to socialize with roommates. “They may feel more stressed than they used to.”
Psychologists also need to be mindful of the shadows that diagnosis can cast, Tasse said. [the patient] “People tend to think that because he has autism or an intellectual disability, that’s why he cries a lot or gets anxious a lot,” she says, “but it’s actually a separate condition that needs to be treated separately, just like any other mental illness.”
Research highlights the need for and gaps in the availability of mental health services. One study published in 2019 based on an online survey of 200 autistic adults living in the UK was bluntly titled, “People like me don’t get support” (Camm-Crosbie, L., Autism, Vol. 23, No. 6, 2019). Of the 200 adults surveyed, 9 in 10 had a mental health diagnosis, most commonly anxiety or depression.
Karin Day sought the help of a psychologist in late 2020 after seeing her 26-year-old autistic son’s anxiety increase significantly during the pandemic. Day said the family tried to shield him from COVID-19 news, but he spends so much time in front of a computer that this was impossible.
Day, who lives in Missouri, said her husband worked part-time and didn’t need to see a psychiatrist until just before the pandemic. “He was having anxiety attacks in the house,” Day said late last year. “I was trying to figure out how to help him. I knew it was beyond my ability.”
But as Day worked her way through the list of clinics that covered her insurance, she felt like she was searching blindly. When her son was younger, there were social media message boards and other resources to help parents of autistic children find specialized clinicians, but as his son became an adult, the options seemed to disappear, Day said. After lots of phone calls, Day found a local psychologist who had availability and experience with autism.