How reliable is a diagnosis of ADHD in adults?

ADHD is classified as a neurodevelopmental disorder. This implies that ADHD starts during childhood and may, or may not, last into adulthood. According to this definition, a diagnosis of ADHD in adults requires two separate criteria to be satisfied: (i) Present diagnostic criteria must be fulfilled and (ii) ADHD symptoms must have started during childhood (before 7 years of age in DSM-IV and 12 years in DSM-5).

It’s relatively easy to evaluate present symptoms and differential diagnoses and to make a clinical decision. However, the second requirement has generated much headache and frustration. Is it really possible to evaluate childhood symptoms in a typical 40 year old patient, decades after the person left school and with limited documentation from family and peers?

Some argue that the criteria of childhood symptoms of ADHD are not satisfied unless there is a well-documented record of child developmental problems. Others put more faith in personal (subjective) recollection of childhood memories. These diverging views have culminated in an intense and heated debate about the possible existence of adult-onset ADHD and whether age-of-onset criteria are meaningful in clinical management of ADHD (1).

We all know from experience that memories tend to fade. Memories cannot be trusted. Research has shown that memories can be systematically biased and manipulated in many ways. Experimental psychology has provided a long list of well documented examples of memory bias, including mood congruent memory bias, consistency bias, positivity effect when older people favor positive over negative information in their memories, suggestibility bias when ideas suggested by the clinician are mistaken for true memories etc. (2). All of these effects and many more are well documented in forensic psychology and popular press and are experienced in routine clinical practise.

Despite of the obvious limitations of retrospective recollection of childhood experiences, a diagnosis of ADHD in adults is routinely based on retrospective reports of childhood experiences, often in the form of semi-structured interviews or rating scales. The Wender Utah Rating Scale (WURS) is the most widely used retrospective rating scale of childhood ADHD symptoms (3). The 25-item version of WURS has acceptable psychometrical properties, but its long-term stability is not known and it is also unclear how WURS scores are affected by other concurrent symptoms and conditions.

To investigate these factors, Lundervold and coworkers recently examined the test–retest reliability of the WURS in 85 adults with ADHD and 189 controls. They found that WURS scores were relatively stable over a time-span of seven years, but also that the scores were strongly influenced by present ADHD symptom severity, as well as other concurrent psychiatric disorders (4).

Based on these observations, the authors conclude that the WURS may be valuable in diagnostic assessments of ADHD, but that clinicians need to be cautious in the interpretation of the results. We all need to be aware of the many factors that can distort recollection of childhood memories. This study also demonstrates how difficult it is to strictly apply the age of onset criteria in adult psychiatric clinical settings.

References

  1. Franke B, Michelini G, Asherson P, Banaschewski T, Bilbow A, Buitelaar JK, Cormand B, Faraone SV, Ginsberg Y, Haavik J, Kuntsi J, Larsson H, Lesch KP, Ramos-Quiroga JA, Réthelyi JM, Ribases M, Reif A.Live fast, die young? A review on the developmental trajectories of ADHD across the lifespan. Eur. Neuropsychopharmacol. 2018 Oct;28(10):1059-1088.
  2. Schacter DL, Dodson CS. Misattribution, false recognition and the sins of memory. Philos Trans R Soc Lond B Biol Sci. 2001 Sep 29;356(1413):1385-93.
  3. Stein MA, Sandoval R, Szumowski E, Roizen N, Reinecke MA, Blondis TA, et al. Psychometric characteristics of the Wender Utah Rating Scale (WURS): reliability and factor structure for men and women. Psychopharmacol Bull 1995;31:425–33.
  4. Lundervold AJ, Vartiainen H, Jensen D, Haavik J. Test-Retest Reliability of the 25-item version of Wender Utah Rating Scale. Impact of Current ADHD Severity on Retrospectively Assessed Childhood Symptoms. J Atten Disord. 2019 Oct 4:1087054719879501.

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