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Mental Retardation and Mental Illness

It’s one of my pet peeves. “He’s having behaviors,” says the new teacher. Argh! I hate that phrase. Of course he’s “having behaviors.” We all have behaviors. When we stop having behaviors, we’re dead. What she means, of course, is that her student is behaving in ways that are difficult, challenging, and unacceptable to her. She wants a behavior plan. She wants to get rid of the difficult behaviors. I want more information. Can we talk?

I think it’s a holdover from the old days. As recently as only thirty years ago, many people in the field thought that people with mental retardation could not have a mental illness. Some people even thought that people with mental retardation didn’t have feelings like the rest of us, or didn’t want to relate to other people, or were too “retarded” to make sense of things.

It’s interesting and humbling to realize that when people are convinced that something is true, they often don’t get confused even by their own observations. Looking through the lens of “he’s retarded,” good-hearted people just didn’t recognize that the people in their families or in their care do feel, think, make sense of things, and, sometimes, are overwhelmed by their feelings and by their situations. Looking through the lens of mental retardation, these well-intended people didn’t consider that cognitively disabled people can have the same biochemical imbalances that cause various mental disorders from depression to schizophrenia. Looking through the lens of mental retardation, these good-hearted people didn’t know that they could help mitigate the cause of the distress by treating it in the same way as they would any other person having a hard time. Instead, they tried to control it.

Current Thinking on Behavior Change

But those were the old days. Behavior change is now recognized as an important clue that something is going on. Experienced caregivers observe, keep careful data, and analyze. Yes, sometimes behavior is a bid for attention, or a way to avoid a task, or a temporary expression of frustration. In those cases, a behavior plan can be very helpful.

But behavior change also can indicate something more serious. Perhaps the person is physically ill. Over 80 percent of psychiatric admissions for people with retardation lead to the discovery of an undiagnosed and untreated medical condition. The most common are urinary tract infections and constipation.

Maybe she or he is reacting to a medicine. Non-psychiatric medicines can produce psychiatric problems which in turn can cause behavior change. For people over age 50 (age 40 for people with Down Syndrome), it can be an indicator of emerging dementia. Or maybe it’s a signal that there is an emerging mental illness. Depending on the study, it is now estimated that 30 to 80 percent of people with mental retardation also have mental health issues. Modern psychiatry and psychological practice recognize that people with retardation suffer from the full range of psychopathology as everyone else, from anxiety and depression to psychosis.

In any of the above situations, a behavior plan not only won’t help, but will either mask or exacerbate the problem. Good analysis leads to a good diagnosis which then informs treatment. And good treatment often then leads to reduction or elimination of behaviors that trouble others.

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How is Mental Illness Diagnosed?

How do we know if someone has a mental illness? Just like people in the general population, people with mild mental retardation can tell a doctor how they feel. Although their language may be more literal and concrete, they can and do talk about their symptoms and what is going on in their lives that is difficult. For these individuals, a psychiatrist or a psychologist can use the same criteria for evaluating symptoms as anyone else. The DSM (Diagnostic and Statistical Manual) which describes the symptoms associated with every mental illness is usually helpful. Medication can be prescribed when appropriate and the person often can take advantage of individual talk therapy or group therapy as well.

But because the DSM relies heavily on self-report of internal states, it is not as useful for people who are more cognitively impaired. For those individuals, behavior change that is observed by family or their staff is the key clue. Generally, we consider the possibility of mental illness when the behavior is consistent across settings; when a consistently applied behavioral intervention doesn’t create change; and when the person seems not to have any control over it.

Behaviors are seen as outward manifestations of the internal states described in the DSM. Anxiety, for example, may be expressed by pacing, restlessness or shouting. Caregivers might report sleeplessness, increased aggression, or trembling. Depression, on the other hand, might be indicated by a general slowing down, irritability, complaints of being tired, refusal to do things that used to give the person pleasure, or a drop in willingness to do self care. If a person starts to cover his or her ears or rub the eyes, brush at unseen things, or talk to the wall, it could be that there are auditory or visual hallucinations. It takes very careful observation and sometimes equally careful questioning of the people who know the person best to begin to understand what the person is experiencing.

Getting Help

If you think a family member with retardation is in psychological distress, it’s important to find a doctor who is knowledgeable in the field. A doctor who has had specific training and experience with people with mental retardation is going to be more sensitive to the unique ways that these individuals show distress and to the ways that they show negative side effects to medication.

We are very fortunate to live in a time when medicines have been developed that can relieve psychiatric suffering. But medicine should be used to treat, not to control. Doctors who have experience in dual mental health and mental retardation diagnosis take the time to attend to the data presented by staff or family and prescribe medicines specifically to address symptoms.

A psychologist or clinical social worker who has experience in the field may be able to suggest changes in the environment, routines, or interactions with family or caregivers that might relieve some of the stress on the person. Sometimes individuals, even individuals with severe retardation, can be taught some ways to relax or calm themselves.

Back to our new teacher: She’s young. She’s new. She doesn’t yet have a lot of experience. But she really does care. She wants the behaviors to stop because the person is hurting himself, because he is hurting others, and because she doesn’t know what to do. Fortunately her supervisor has been in the field for awhile. She knows that people with retardation really are fundamentally just like everyone else. So his parents will be called in to compare notes, data will be analyzed, a doctor will be consulted, and every effort will be made to figure out what is going on. Our new teacher will learn and grow into her job. The student will be given the relief and dignity of treatment instead of being merely controlled. It’s been a good day.

Mental Retardation and Mental Illness

Marie Hartwell-Walker, Ed.D.

Marie Hartwell-WalkerDr. Marie Hartwell-Walker is licensed as both a psychologist and marriage and family counselor. She specializes in couples and family therapy and parent education. She writes regularly for Psych Central as well as Psych Central's Ask the Therapist feature. She is author of the insightful parenting e-book, Tending the Family Heart.

Check out her book, Unlocking the Secrets of Self-Esteem.

APA Reference
Hartwell-Walker, M. (2020). Mental Retardation and Mental Illness. Psych Central. Retrieved on September 28, 2020, from
Scientifically Reviewed
Last updated: 17 Jan 2020 (Originally: 17 May 2016)
Last reviewed: By a member of our scientific advisory board on 17 Jan 2020
Published on Psych All rights reserved.