Cognitive difficulties are common in persons experiencing anxiety or mood disorders. In this paper we explore the economic concept of rational decision-making in young people with emerging mood disorders by using incentive-compatible experiments involving choices over consumer products. At two time points, separated by six to eight weeks, we measured irrational decision-making (defined as violations of the Generalized Axiom of Revealed Preference) concurrently with levels of anxiety and depression levels using Kessler Psychological Distress (K10), Quick Inventory of Depressive Symptomology (QIDS-A17) and Somatic and Psychological Health Report (SPHERE-12) in 30 participants (mean age 19.22 years, 19 male) attending a youth mental health clinic. In total, 15 (50%) participants rated high on all three psychological questionnaires combined, scoring "severely" depressed (QIDS-A17 ≥16), severely" anxious (K10 ≥30) and "Level 1 (Type 1)" for SPHERE-12. In Session 2, taking attrition into account, we estimated that of our returning 25 patients, 11 (44%) participants continued to rate high on all three psychological scores. We found that the degree of economic irrationality was higher in young people with more severe mood disorder symptoms (anxiety measured by K10, Pearson's correlation r = 0.406, p = 0.026). These results may have implications for both characterization and treatment of common mood disorders in young people.

Evaluating decision-making during youth is a complex area of research. Multiple factors influence the young person’s subjective decision-making at this stage of development. Sub-optimal decision-making can have lifelong consequences. Longer adolescence, life stressors, drugs and alcohol and adverse events impact the young person, making them vulnerable to emerging mood disorders, such as anxiety and depression. Behavioural economics with its cognitive and multidisciplinary approach examines decision-making in youth with emerging mood disorders, but few empirical studies exist outside of a laboratory setting. Of the few that apply a multidisciplinary approach, most focus on other mental disorders. This review qualitatively evaluates the decision science literature to firstly, investigate complex factors influencing decision-making between adolescence and young adulthood. Secondly, it investigates studies that have applied either a cognitive or multidisciplinary approach to evaluate how young people choose. With respect to the studies identified, this review found that as opposed to depression, clinical anxiety (trait) and its relationship to youth decision-making has not been well researched using the multidisciplinary approach. Studies that did apply this approach found that mood disordered young individuals overall performed worse than healthy controls. This review argues that applying the multidisciplinary approach to study subjective decision-making can provide an alternative measure to empirically evaluate early stages of psychopathology in a youth population. Investigating the critical time points where the decision process itself impacts affective states in individuals could further elucidate some of the challenges currently faced in decision-making studies.