The Feasibility, Acceptability, and Efficacy of Positive Search Training for Irritable Youth: A Single-Case Experimental Design

Although irritability is common in youth, research on treatment is in its infancy. Threat biases are more pronounced in irritable compared to low irritable youth, similar to evidence found in anxious youth. Therefore, interventions targeting these biases may be promising for reducing irritability. This study utilised a multiple baseline case series design to determine the feasibility, acceptability, and efficacy of positive search training (PST) for irritable children. Three children were included who met criteria for a principal diagnosis of Disruptive Mood Dysregulation Disorder (DMDD), and a secondary diagnosis of Attention Deficit Hyperactivity Disorder (ADHD) or Major Depressive Disorder (MDD). PST was feasible with two of the three participants; one child refused to continue after one session. For the two participants who completed PST, acceptability was stable with moderate-to-high ratings of engagement and enjoyment, and high and stable treatment-relevant verbalisations of the key strategies. Both cases showed declines in DMDD severity across treatment and no longer met criteria at post-treatment. Both participants met criteria for Oppositional Defiant Disorder (ODD) at post-treatment (considered less severe for irritability than DMDD). Declines in parent-reported irritability occurred for both cases, however some returns to baseline were observed. Overall, PST for irritable youth shows promise as an acceptable and feasible intervention. Further studies are needed combining PST with strategies for secondary diagnoses, given its high comorbidity with disruptive behaviour disorders.