ACTsocially: The (Dis)Similarities of ACT for Changing Internalizing and Externalizing Symptomatology in Adolescence

Adolescence represents vulnerability to mental health issues, with approximately 1 in 7 adolescents presenting mental disorders that, when untreated, lead to significant impairments and less long-term quality of life. Given that adolescents are hypersensitive to social stimuli and social exclusion, and place particular value in peer approval/influence, peer rejection in adolescence seems to increase the risk for developing mental disorders. Conversely, positive peer relationships may protect against mental health problems and promote resilience. This buffering effect may be absent in disorders related to adolescents' social functioning.

Oppositional Defiant Disorder (ODD) and Social Anxiety Disorder (SAD) are polarizing examples of problematic social functioning as adolescents with these diagnoses view the social world as a place of potential evaluation and rejection. ODD and SAD have alarming lifetime prevalence rates in adolescence, suggesting that these conditions are highly stable and predict later emotional and behavioral problems. Though their impact on socialization is similar (i.e., rejection, isolation), they have been differently conceptualized and intervened with (e.g., self-focused attention in SAD versus hostile attribution style in ODD).

Alternatively, Acceptance and Commitment Therapy (ACT) focuses on common underlying processes, rather than specific symptoms, as the foundation for social difficulties such as ODD or SAD. Specifically, Psychological Inflexibility (PI) - rigid attempts to control internal experiences and the inability to adapt one's behavior in the service of freely chosen values - is proposed as the basis of human suffering. PI stems from six interrelated processes: Cognitive Fusion, Experiential Avoidance, Attachment to the Conceptualized Self, Dominance of the Conceptualized Past/Feared Future, Lack of Values Clarity, and Inaction, Impulsivity or Avoidant Persistence. ACT aims to cultivate Psychological Flexibility (PF) - the ability to be in the present moment with willingness to be with the internal experience non-judgmentally and to act in a way that is congruent with ones' values. ACT relies on 6 core principles to cultivate PF, each opposing to one of the PI processes: Acceptance, Cognitive Defusion, Contact with Present Moment, Self-As-Context, Values, and Committed Action. Although there is evidence about PI processes as transdiagnostic factors underlying psychopathology and about the efficacy of ACT on adults' mental health in comparison with control conditions, research targeting adolescent samples (though emerging) is lacking.

Research has supported the efficacy of ACT interventions in adults with externalizing behavior. However, only a few works used ACT to address externalizing behavior in adolescents, though results were promising. There is evidence supporting the efficacy of ACT in treating SAD, though, again, only a few studies addressed this issue and found promising outcomes with adolescents. None of these works considered change in the processes of PI/PF and its intercorrelation with change in symptomatology, nor ACT's potential to promote similar change in these polarizing examples of problematic social functioning.

To overcome these shortcomings, we propose to take an ACT approach to adolescent ODD and SAD in a sequence of three clinical trials: A pilot single-arm clinical study of ACT applied to ODD, a Randomized Controlled Clinical Trial of ACT applied to SAD, and an equivalence clinical trial of ACT applied to ODD and SAD. These studies will be conducted to explore the (dis)similarity in efficacy of ACT for ODD and SAD, considering symptomatology, PI/PF processes and mental health as outcomes.