European Child & Adolescent Psychiatry

While many psychiatric disorders are associated with an increased risk for suicidal behaviors (SB) in children and adolescents, a few studies have explored the role of clinical symptoms based on a dimensional approach. Irritability is seen as a marker, a general psychopathology, and a symptom of both externalizing and internalizing disorders. In this review, we are interested in determining whether and how irritability can predict SB in youth. First, we reviewed consistencies and variation in the literature linking irritability to suicidal ideation (SI) and suicide attempt (SA). Second, based on the available models, we proposed specific mechanistic pathways, whereby irritability may modulate the risk for SB. Irritability has been found associated with SB both in cross-sectional and in longitudinal studies. The relation is consistent in different settings (i.e., general population and clinical settings) and across psychiatric disorders. The association is reduced but persists after adjusting for psychiatric disorder, including depression. On one hand, irritability constitutes a risk factor for SI via the onset of internalized disorder. On the other hand, irritable youth may be more prone to attempt suicide when experiencing SI. The measures for irritability were heterogeneous. A limited number of studies were designed to explore the role of mediators and/or moderators. Recognizing irritability in children and adolescents is a key issue with regards to suicide prevention.

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed neurodevelopmental disorder in childhood and is characterized by inattention, impulsivity, and hyperactivity. Observations of distributed functional abnormalities in ADHD suggest aberrant large-scale brain network connectivity. However, few studies have measured the voxel-wise network centrality of boys with ADHD, which captures the functional relationships of a given voxel within the entire connectivity matrix of the brain. Here, to examine the network patterns characterizing children with ADHD, we recruited 47 boys with ADHD and 21 matched control boys who underwent resting-state functional imaging scanning in a 3.0 T MRI unit. We measured voxel-wise network centrality, indexing local functional relationships across the entire brain connectome, termed degree centrality (DC). Then, we chose the brain regions with altered DC as seeds to examine the remote functional connectivity (FC) of brain regions. We found that boys with ADHD exhibited (1) decreased centrality in the left superior temporal gyrus (STG) and increased centrality in the left superior occipital lobe (SOL) and right inferior parietal lobe (IPL); (2) decreased FC between the STG and the putamen and thalamus, which belong to the cognitive cortico-striatal–thalamic–cortical (CSTC) loop, and increased FC between the STG and medial/superior frontal gyrus within the affective CSTC loop; and (3) decreased connectivity between the SOL and cuneus within the dorsal attention network. Our results demonstrated that patients with ADHD show a connectivity-based pathophysiological process in the cognitive and affective CSTC loops and attention network.