Sluggish Cognitive Tempo Profiles Among Young Adults with ASD

Background: Sluggish cognitive tempo (SCT) refers to a set of behavioral and cognitive symptoms characterized by a sluggish activity level, slow processing, daydreaming, and mental fogginess (Becker et al., 2016). Despite similarities between SCT and attention-deficit/hyperactivity disorder (ADHD), research has shown SCT to be distinct from ADHD with its own behavioral phenotype and independently associated psychiatric comorbidities (Barkley, 2012; Becker et al., 2017; Reinvall et al., 2017). Despite the high comorbidity of ADHD for individuals with autism spectrum disorder (ASD), limited research has explored SCT symptomology in an ASD sample.

Objectives: The current study aimed to characterize the relationship between SCT and ADHD in an ASD sample. We also sought to determine if SCT symptoms are independently associated with co-occurring symptoms of anxiety and depression in adults with ASD, controlling for ADHD symptoms.

Methods: Participants included 30 young adults with ASD (Mean age (in years) =20.10, SD =2.00). Participants’ parents completed the Adult Behavior Checklist (ABCL; Achenbach & Rescorla, 2003), a parent-report measure of behavioral, emotional, and social problems for adults. T-scores for the SCT, ADHD, anxiety, and depression scales were used as measures of participants’ psychiatric symptoms.

Results: Descriptively, there was variability in participants’ SCT scores, with 20 percent of participants meeting borderline clinical cut-offs for SCT symptoms and an additional 40 percent meeting for clinically significant cut-offs. Participants’ ADHD and SCT T-scores were significantly correlated, r = .689, p < .001. Partial correlations revealed that participants’ SCT scores were significantly correlated with depression symptoms when controlling for ADHD symptomology, r = .495, p < .010. However, participants’ SCT scores were not significantly correlated with anxiety symptoms when controlling for ADHD symptomology, r = .190, p > .050.

Conclusions: Results suggest that individuals with ASD experience a range of SCT symptoms, which are strongly positively related to ADHD symptoms. Despite this strong association with ADHD, SCT symptomology appears independently related to depressive symptoms, with adults with ASD and high SCT symptoms experiencing more depressive symptoms. Given the shared behavioral symptoms between SCT and depression (e.g. lack of motivation, cognitive dulling, fogginess) and previous studies finding SCT and depression to be related in non-ASD samples (Becker et al., 2016), SCT and depression may be uniformly related and not specific to ASD. These findings also support the theory that SCT may be its own construct distinct from ADHD. However, SCT was not independently associated with anxiety symptoms, contrary to findings on children and adolescents from the only other study to analyze SCT in an ASD sample (Reinvall et al., 2017). Additional research with a larger sample size is necessary to further distinguish SCT as an independent behavioral construct related to ASD and identify if SCT independently affects functioning among young adults with ASD. Determining how SCT symptomology impacts the behavioral and emotional ASD profile could lead to better understanding of the disorder and improved efficacy of interventions to maximize positive outcomes for this population.