Differences at brain SPECT between depressed females with and without adult ADHD and healthy controls: etiological considerations

Ann Gardner,Stig A Larsson,Marco Pagani,Hans Jacobsson,Susanne Bejerot,Dario Salmaso,Alejandro Sanchez-Crespo,Andrea Varrone

doi:10.1186/1744-9081-5-37

Abstract

BackgroundComorbidity between Attention Deficit Hyperactivity Disorder (ADHD) and mood disorders is common. Alterations of the cerebellum and frontal regions have been reported in neuro-imaging studies of ADHD and major depression.MethodsThirty chronically depressed adult females of whom 16 had scores below, and 14 scores above, cut-offs on the 25-items Wender Utah Retrospective Scale (WURS-25) and the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS) were divided into subgroups designated "Depression" and "Depression + ADHD", respectively. Twenty-one of the patients had some audiological symptom, tinnitus and/or hearing impairment. The patients were investigated with other rating scales and 99mTc-HMPAO SPECT. Controls for 99mTc-HMPAO SPECT were 16 healthy females. SPECT was analyzed by both statistical parametric mapping (SPM2) and the computerized brain atlas (CBA). Discriminant analysis was performed on the volumes of interest generated by the CBA, and on the scores from rating scales with the highest group differences.ResultsThe mean score of a depression rating scale (MADRS-S) was significantly lower in the "Depression" subgroup compared to in the "Depression + ADHD" subgroup. There was significantly decreased tracer uptake within the bilateral cerebellum at both SPM and CBA in the "Depression + ADHD" subgroup compared to in the controls. No decrease of cerebellar tracer uptake was observed in "Depression". Significantly increased tracer uptake was found at SPM within some bilateral frontal regions (Brodmann areas 8, 9, 10, 32) in the "Depression + ADHD" subgroup compared to in "Depression". An accuracy of 100% was obtained for the discrimination between the patient groups when thalamic uptake was used in the analysis along with scores from Socialization and Impulsivity scales.ConclusionThe findings confirm the previous observation of a cerebellar involvement in ADHD. Higher bilateral frontal 99mTc-HMPAO uptake in "Depression + ADHD" compared to in "Depression" indicate a difference between these subgroups. 99mTc-HMPAO uptake mechanisms are discussed.

Highlights

Comorbidity between Attention Deficit Hyperactivity Disorder (ADHD) and mood disorders is common
Subgrouping of patients according to ADHDquestionnaires and interview The patients with low WURS-25 and Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS) scores were designated as the "Depression" subgroup (N = 16), and the patients with high WURS-25 and WRAADDS scores as the "Depression + ADHD" subgroup (N = 14)
Since age differed between the patient subgroups, it was considered as a nuisance variable in the comparisons between "Depression + ADHD" and "Depression" at both SPM2 and computerized brain atlas (CBA)

Summary

Introduction

Comorbidity between Attention Deficit Hyperactivity Disorder (ADHD) and mood disorders is common. Alterations of the cerebellum and frontal regions have been reported in neuro-imaging studies of ADHD and major depression. In 1998, it was suggested that ADHD may be "the most common chronic undiagnosed psychiatric disorder in adults" [1]. Lifetime mood disorder was reported by 53% of the patients with adult-ADHD, versus in 28% of the controls, in a study [4]. An earlier age of onset of major depression, and a comorbidity of 87% with at least one other psychiatric disorder, was reported in a study of adult-ADHD subjects compared with non-ADHD subjects [6]. For the psychiatric and somatic comorbidity with adult-ADHD, see [Additional file 1]

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