A New Rating Scale to Assist in Diagnosing ADHD in Adults

Although as recently as the 1980s it was widely believed that ADHD was a self-remitting condition that would invariably abate following puberty, it is now been clearly demonstrated that ADHD often persists beyond adolescence and into adulthood. In fact, it has been shown in several longitudinal studies that between 50-65% of children diagnosed with ADHD continue to demonstrate symptoms as they reach adulthood, while upwards of 30% continue to show the full syndrome (i.e. continue to meet full diagnostic criteria).

As the awareness of ADHD among adults has grown, so has the number of individuals seeking evaluation and treatment for this condition. More and more, professionals are being called upon to evaluate adult patients for ADHD. The problem is, making the diagnosis in adults is even more demanding, many believe, than making the diagnosis in children.

There are several reasons for this. First, our understanding of the phenomenology of ADHD in adulthood (i.e. what does ADHD really "look like" in adults and what areas of adult functioning are affected) is still evolving. Certainly, it would not be surprising if how ADHD is manifested in adults would be quite different from how it presents in a school-age child. Second, the official diagnostic criteria presented in DSM-IV were developed on the basis of field testing with 4-16 year olds. Thus, many of the items listed in the diagnostic criteria may not really be appropriate for use with adults. Third, in a comprehensive evaluation of a child, information from multiple sources is collected - generally parents, teachers, and from the child his or herself. With adults, however, collecting multiple sources of information on the adult's symptoms can be complicated. For example, performance at work might be a critical dimension in establishing the diagnosis, but, understandably, many adults would be reluctant to have their physician or psychologist speak to their boss or coworkers, or to even ask their co-workers to fill out a report on their behavior. Finally, there is the need to establish that the ADHD symptoms an adult is manifesting were clearly evident earlier in life (i.e. the current criteria require that there be evidence of some impairment from symptoms prior to age 7). When such symptoms emerge for the first time later in life, with no prior evidence of their occurrence, the diagnosis of ADHD would not be made. The best way to corroborate this is through direct interviews with an adult's parents, and, from examining school records from as far back as they are available. This, too, can be difficult and objectionable to many adults seeking assistance.

Another obstacle to careful diagnostic evaluations for adults is the relative absence of empirically validated rating scales to use as aids in the evaluation process. Several such behavior rating scales are available for use with children and teens - the most commonly used being the Child Behavior Checklist, the Conners Rating Scales, and the Behavioral Assessment System for Children. For adults, however, no such well-validated instrument has been available.

That is why I was so pleased to come across two studies published in the October, 1999 issue of the Journal of Attention Disorders that describes the development of a self-report rating scale for ADHD in adults. (Conners, C.K., et al., (1999). Self-ratings of ADHD symptoms in adults I: Factor structure and normative data. Journal of Attention Disorders, 3, 141-151. Study 2: Self-ratings of ADHD symptoms in adults II: Reliability, validity, and diagnostic sensitivity. Journal of Attention Disorders, 3, 153-158). I wanted to include a summary of this work in ADHD RESEARCH UPDATE not only because it may be useful for you to know about this instrument, but also because this work sheds important light on how ADHD presents in adulthood.

To construct the rating scale, the authors began by identifying 9 different domains of functioning that they believed would be impaired in adults with ADHD. These domains were:

1) Inattention/problems with concentration
2) Hyperactivity/Restlessness
3) Impulsivity/problems with concentration
4) Problems with organization, time awareness, and planning
5) Problems with memory
6) Problems with self-concept
7) Interpersonal problems
8) Problems with learning, and
9) Problems with mood - this included poor frustration tolerance, irritability, and a tendency to overreact emotionally.

After identifying these different domains, the authors then wrote approximately 10 different questionnaire items for each domain. For example, for domain 1 - Inattention/problems with concentration - they wrote 10 items that they felt tapped into the way these types of difficulties would show up in adults. This resulted in an initial pool of 93 items that were derived from various sources including DSM-IV, rating scales that are used for children and teens, clinical impressions, and current conceptualizations of ADHD in adults.

Once the item pool was developed, the "test" was administered to 839 "normal adults" (slightly more females than males) as well as to 167 adults who had been carefully evaluated to confirm a diagnosis of ADHD (97 males and 70 females). The responses provided by this sample of adults was then "factor analyzed" to identify which items would be retained for use on the final scale. (Factor analysis is a statistical technique that enables one to determine how individuals items in a test should be combined into groups of items that appear to be measuring a common attribute. The groups of items that people tend to respond to in a similar manner are called "factors". By examining the individual items in the factor and seeing what they have in common, you can then make a judgment about what attribute the different items are measuring. Items that do not seem to "fit" well with any factor - this is also determined statistically - are then dropped from the test.)

Results

The factor analysis resulted in the identification of 4 separate factors that contained 43 of the original 93 items. These 4 factors - you can think of them as individual scales - represent the "domains of functioning" that emerged as the most important from the original pool of items. I will list each factor and the abbreviations of the items below because this provides a good picture of the types of difficulties that are characteristic of adults with ADHD. (Note: Each item was rated by participants on a 0 for "not at all true" to 3 for "very much true" scale).

Factor 1- Inattention/memory Problems

disorganized
forgets to remember things
lose things I need
don't plan ahead
depend on others for order
hard to keep track of several things
don't finish things
need deadline to get things done
trouble getting started
change plans/jobs midstream
absent-minded
misjudge time

Factor 2 - Hyperactivity/restlessness

squirm or fidget
can't sit still
up and on the go
feel restless when still
always moving
hard to stay in one place for long
effort to sit still
like to do active things
bored easily
risk-taker
don't like quiet activities
seek out fast-paced activities

Factor 3 - Impulsivity/emotional Lability

say things without thinking
short fuse
blurt out things
easily frustrated
often wish I could take back comments
annoy other people
throw tantrums
step on people's toes
moods unpredictable
interrupt others when talking
things set me off easily
irritable

Factor 4 - Problems With Self-concept

not sure of self
wish I had greater confidence
get down on self
act ok outside but unsure of self
hard to believe in self
avoid new challenges

(Note: Please be aware that although these items seemed to do a good job of discriminating between adults with and without ADHD, this should in no way be used as a means for self-diagnosis. An adult's self-report on a measure like this is only one part of a thorough diagnostic evaluation, and can not be used in isolation for diagnostic purposes. If you believe that many of these items are characteristic of you, and describe problems that you are experiencing, then consulting with a mental health professional is an option to consider.)

It is interesting to compare the content of the items above with the official diagnostic criteria in DSM-IV. When you do this, you will see that although there is certainly some important similarities between the two sets of items, there are also items found on this new adult rating scale that are quite different from the items that had been developed on a much younger population. This, of course, is not surprising as one would expect that ADHD would not necessarily appear identical in adults as it does in children.

When examining the scores on these factors for all participants (i.e. this includes subjects in the normative group as well as those adults who had been diagnosed with ADHD), there were some very interesting differences with respect to gender and age that were found. Across 4 different age ranges (i.e. 18-29; 30-39; 40-49, and 50+), a decline in participants' scores was found for self-reported problems with inattention, hyperactivity, and impulsivity. In other words, older participants tended to report fewer problems in these areas than younger participants.

Regarding gender differences, males reported significantly more problems with inattention, hyperactivity, and impulsivity. Females, however, reported greater problems than males in the area of self-concept. (Note: Remember, these results are based on all participants - both those in the normative group and those adults with ADHD. For reasons that I don't understand, age and gender results specifically for those participants with ADHD are not presented).

The final aspect of the study was an attempt to validate the newly created measure by seeing how well scores on the measure were able to differentiate between adults with and without ADHD. This portion of the study included 39 adults diagnosed with ADHD (these adults were not part of the group used to create the measure) and 39 adults from the initial pool who were matched on age and gender. There were 16 females in each group.

Not surprisingly, the adults with ADHD reported significantly greater difficulty in all 4 areas: attention/memory problems, hyperactivity/restlessness, impulsivity/emotional lability, and problems with self-concept. The authors also performed a statistical test called discriminant function analysis to determine how accurately individuals would be classified as being ADHD or control subjects based on their responses to the rating scale items. Of the 39 adults who were diagnosed with ADHD via other means (i.e. a structured psychiatric interview) 32 were classified as having ADHD based on their scores. Of the 39 adults without ADHD, only 5 were classified as having ADHD based on their responses. This degree of sensitivity and specificity is actually quite good for these types of instruments. The misclassifications that result, however, point out the real problems with basing a diagnostic decision on behavioral rating scale data alone, and highlight the importance of conducting a comprehensive evaluation of which such rating scale data is just one component.

Summary And Implications

In addition to providing clinicians and researchers with a reliable instrument to assist in the diagnosis of ADHD in adults, another useful contribution of this work is the light it sheds on the variety of ways that ADHD tends to be experienced during adulthood. The item list presented above - although it should not be used for the purpose of self-diagnosis - provides a good overview of the types of problems that adults with ADHD frequently experience. Some of these "symptoms" are quite similar to what characterizes ADHD among children and adolescents, but others appear to do a much better job of capturing how ADHD may continue to impact the functioning of many adults.

As the authors note, there is additional work on the validation of this measure that remains. In particular, it will be important to contrast the responses of adults with ADHD on this scale not just to other adults without ADHD, but also to adults with other types of psychiatric diagnoses (e.g. depression) to be certain that the scale is useful in distinguishing between ADHD and other types of psychiatric difficulties. I imagine that such work is ongoing.

For practitioners interested in using this newly developed instrument in their own work, information about ordering it can be found at www.mhs.com.

Note: This article originally appeared in Attention Research Update, an online newsletter written by Dr. David Rabiner, a Duke University psychologist and former member of CHADD's Professional Advisory Board. You can learn more about Attention Research Update and sign up for a free subscription at www.helpforadd.com.

Reproduced with permission of David Rabiner, Ph.D. - HelpforADD.com