Frontoparietal function in young people with dysthymic disorder (DSM-5: Persistent depressive disorder) during spatial working memory.
BACKGROUND
Dysthymic disorder (DD) is a depressive disorder characterised by persistent low and/or irritable mood and has been identified as a major risk factor for developing major depressive disorder (MDD). MDD and DD have been associated with executive function difficulties of working memory and attention. Little is known about how executive function networks in the brain are affected in children and adolescents with MDD and even less in DD. This study used fMRI and two spatial working memory paradigms to investigate associated brain function in young people with DD and an age-, gender- and IQ- matched typically developing group.


METHODS
Nineteen male patients with DD (mean age 11.2±1.5 years) diagnosed according to DSM-IV criteria and 16 typically developing boys (mean age 10.5±1.1 years) performed a mental rotation and a delay-match to sample (DMTS) task while undergoing fMRI. All participants were medication-naïve at the time of testing.


RESULTS
Compared to typically developing young people, the DD group showed less activation in left frontal regions including left ventro- and dorsolateral prefrontal cortices (PFC) during mental rotation. Medial frontal regions including dorsomedial PFC, anterior cingulate cortex and frontal pole also showed relatively reduced activation. During the DMTS task patients showed significantly more activation in the right precuneus and posterior cingulate cortex.


CONCLUSIONS
This was a cross-sectional study with a small sample limiting the generalizability of the results.


CONCLUSIONS
The results complement previous findings in adults with MDD that have shown differential activation of left PFC regions during working memory tasks. Additionally, altered function of cortical midline structures in young patients with DD was identified. This supports findings in children, adolescents and adults with MDD suggesting that the pathophysiology of depressive disorders extends to DD as a risk factor for MDD and exhibits continuity over the lifespan.
Developmental Imaging, Murdoch Childrens Research Institute, Parkville, VIC, Australia; Academic Child Psychiatry Unit, Department of Paediatrics, University of Melbourne, Royal Children׳s Hospital, Parkville, Melbourne 3062, VIC, Australia.
Veronika
V
Vilgis
Developmental Imaging, Murdoch Childrens Research Institute, Parkville, VIC, Australia.
Jian
J
Chen
Developmental Imaging, Murdoch Childrens Research Institute, Parkville, VIC, Australia.
Timothy J
TJ
Silk
School of Psychology and Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
Ross
R
Cunnington
Developmental Imaging, Murdoch Childrens Research Institute, Parkville, VIC, Australia; Academic Child Psychiatry Unit, Department of Paediatrics, University of Melbourne, Royal Children׳s Hospital, Parkville, Melbourne 3062, VIC, Australia. Electronic address: alasdair.vance@rch.org.au.
Alasdair
A
Vance
D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D019263:Dysthymic Disorder / Q000503:physiopathology*; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010296:Parietal Lobe / Q000503:physiopathology*; D065852:Spatial Memory / Q000502:physiology*
Children; Dysthymic disorder; Pediatric; Persistent depressive disorder; Working memory; fMRI