Differential effects of anxiety and depressive symptoms on working memory components in children and adolescents with ADHD combined type and ADHD inattentive type

Examining Distinctive Working Memory Profiles in Chinese Children With Predominantly Inattentive Subtype of Attention-Deficit/Hyperactivity Disorder and/or Reading Difficulties

Although evidence has shown that both RD and ADHD-I children suffer from working memory problems, inconsistencies in impaired modalities have been reported. This study aimed to (1) compare the three WM domains (i.e., verbal WM, visual-spatial WM, and behavioral WM) among pure ADHD-I, pure RD, comorbid ADHD-I+RD, and typical control groups and (2) examine the impact of comorbidity on the three WM domains. A Chinese sample of participants from Hong Kong included 29 children in the ADHD-I group, 78 children in the RD group, 31 children in the comorbid group (ADHD-I+RD), and 64 children in the TD control group. All participants completed the assessments individually. The findings showed that the children with ADHD-I and/or RD exhibited diverse cognitive profiles. In particular, RD was associated with verbal and visual-spatial working memory deficits, while ADHD-I was associated with behavioral working memory deficits. Interestingly, the comorbid condition demonstrated additive deficits of the two disorders but with greater deficits in behavioral working memory. These findings support the cognitive subtype hypothesis and provide a clearer picture of the distinctive working memory profiles of different groups, allowing for the development of intervention programs in the future.

Spatial working memory performance in children and adolescents with major depressive disorder and dysthymic disorder

BACKGROUND

Spatial working memory (SWM) is known to be impaired in children with Major depressive disorder (MDD), and, separately, Dysthymic disorder (DD) (DSM V persistent depressive disorder equivalent). Yet, it remains unclear whether MDD or DD is associated with worse SWM impairment, whether DD adds to the SWM impairments evident in MDD and whether these findings are evident in children as well as adolescents with MDD and DD.

METHODS

The association of SWM and its strategy and spatial span components is explored in carefully defined children and adolescents (age 6-16 years) with MDD alone (N = 29), MDD and DD (N = 130), DD alone (N = 154) compared to healthy typically developing participants (N = 107), controlling for age, gender, full scale IQ and social adversity status. The relationship between SWM and its strategy and span components and anxious/depressed and inattentive symptoms were also examined.

RESULTS

MDD was associated with worse SWM impairment than DD and there was no evidence of an additive effect of MDD and DD on SWM, strategy and spatial span deficits. Further, these findings were age-independent.

LIMITATIONS

The data presented are cross sectional and limited to SWM deficits in MDD and/or DD.

CONCLUSIONS

This study concurs with and extends current influential models about the cognitive effects of MDD and DD. Clinical implications and future research directions are discussed.

Prevalence and diagnostic validity of motivational impairments and deficits in visuospatial short-term memory and working memory in ADHD subtypes

Deficits in working memory (WM) and reinforcement sensitivity are thought to give rise to symptoms in the combined (ADHD-C) and inattentive subtype (ADHD-I) of ADHD. Children with ADHD are especially impaired on visuospatial WM, which is composed of short-term memory (STM) and a central executive. Although deficits in visuospatial WM and reinforcement sensitivity appear characteristic of children with ADHD on a group-level, the prevalence and diagnostic validity of these impairments is still largely unknown. Moreover, studies investigating this did not control for the interaction between motivational impairments and cognitive performance in children with ADHD, and did not differentiate between ADHD subtypes. Visuospatial WM and STM tasks were administered in a standard (feedback-only) and a high-reinforcement (feedback + 10 euros) condition, to 86 children with ADHD-C, 27 children with ADHD-I (restrictive subtype), and 62 typically developing controls (aged 8-12). Reinforcement sensitivity was indexed as the difference in performance between the reinforcement conditions. WM and STM impairments were most prevalent in ADHD-C. In ADHD-I, only WM impairments, not STM impairments, were more prevalent than in controls. Motivational impairments were not common (22% impaired) and equally prevalent in both subtypes. Memory and motivation were found to represent independent neuropsychological domains. Impairment on WM, STM, and/or motivation was associated with more inattention symptoms, medication-use, and lower IQ scores. Similar results were found for analyses of diagnostic validity. The majority of children with ADHD-C is impaired on visuospatial WM. In ADHD-I, STM impairments are not more common than in controls. Within both ADHD subtypes only a minority has an abnormal sensitivity to reinforcement.