ADHD again in the spotlight, thanks to Sluggish Cognitive Tempo?!
Even though pediatricians, psychologists, and scientists agree that ADHD is one of the most common developmental disorders in children, with symptoms persisting throughout adulthood, the validity of the diagnostic criteria of ADHD has often been questioned. ADHD criteria focus equally on attentional deficits and on hyperactive or impulsive symptoms. The current 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) states that “children must have at least six symptoms from either (or both) the inattention group of criteria and the hyperactivity and impulsivity criteria, while older adolescents and adults (over age 17 years) must present with five.” (American Psychiatric Association, 2014).
“More recently, there has been an increase in individuals who were referred to clinicians for an ADHD assessment but who, despite the presence of severe impairments in attention, did not meet the diagnostic criteria for ADHD.”
Nevertheless, their impairments in attention were sometimes significantly more severe than those typically seen in individuals with ADHD. Individuals with these severe attentional impairments are often described as slow, absent-minded, and inclined to daydreaming. Experts have clustered this set of symptoms under the term “Sluggish Cognitive Tempo” (SCT).
While the 3rd edition of the DSM included items that represented symptoms of SCT for the diagnosis of ADHD, these items were removed in the 4th edition of the DSM and were not reintroduced in the current DSM-5. Some researchers claim that, due to the removal of these items, we miss a significant proportion of patients who should actually be treated for their attentional deficits. After a period of excessive public debates on whether ADHD is a real disorder or not, ADHD seems to be going to face another controversy, yet, a less discussed and less studied one. Namely, whether SCT is a valid or even distinct disorder from ADHD. Our research group recently published a review on the existing literature on SCT. We did this to outline the clinical validity of the symptoms that many patients report, and to elucidate the psychometric validity of the approaches used in the assessment of SCT (Mueller et al, 2014). Even though there has been interest in SCT since the early 1980s, empirical research on SCT has only increased recently.
So far, SCT has been most closely associated with childhood ADHD, but also it has most often been examined in children with ADHD. Especially the predominantly inattentive type of ADHD was found to show a strong association with SCT symptoms. However, in more recent studies, SCT symptoms were also detected in children with Fetal Alcohol Syndrome and in children that survived leukemia, even though studies in non-ADHD groups are still rather rare.
“One of the major pitfalls in researching SCT is that there is no consensus yet on how to best measure SCT.”
This lack of consensus is one of the leading causes of why some researchers challenge the current scientific interest in SCT. In an interview with the New York Times, Editorial Board Member of the Journal of Abnormal Child Psychology Dr. Steve S. Lee stated: “The scientist part of me says we need to pursue knowledge, but we know that people will start saying their kids have it, and doctors will start diagnosing it and prescribing for it long before we know whether it’s real. ADHD has become a public health, societal question, and it’s a fair question to ask of SCT. We better pump the brakes more diligently.”
“Nevertheless, findings on the psychometric validity of some of the SCT measures support the overall existence of SCT.”
However, current SCT measures vary from scales with only 2 items up to scales with 17 items. Given the great variety of SCT measures that are currently used, a consensus in the measurement of SCT should be established first. This does not take away that the clinical value of SCT should be the engine underlying research on SCT. Even though a consensus in the measurement of SCT is highly needed, we concluded that the assessment of SCT has a great value in individuals with developmental disorders but also in individuals with internalizing or neurological disorders. We proposed that the inclusion of SCT items in the clinical setting in general would not only reduce the current over-diagnosing of individuals with ADHD combined type, but could also yield additional insights into the cognitive and emotional deficits of other clinical populations.
Nevertheless, current research on SCT lacks studies that focus on the general functioning of individuals with SCT symptoms. Future studies should unravel the link between SCT symptoms and possible everyday-life impairments as well as social and cognitive impairments. With our review, we hope to promote more awareness for the current pitfalls and accomplishments associated with research on SCT.
Mueller, A. K., Tucha, L., Koerts, J., Groen, Y., Lange, K. W., & Tucha, O. (2014). Sluggish cognitive tempo and its neurocognitive-, social- and emotive correlates: a systematic review of the current literature. Journal of Molecular Psychiatry, 2(5). DOI: 10.1186/2049-9256-2-5
Image by Kathi Mueller