Armstrong et al. Longitudinal Associations Between Internalizing and Externalizing Comorbidities and Functional Outcomes for Children with ADHD Child Psychiatry and Human Development
Overview: This paper addresses two somewhat opposing types of ADHD comorbidites. The authors discuss how both externalizing (conduct disorder, ODD, hyperactivity) and internalizing (anxiety, depression) burdens are both highly comorbid with ADHD. They discuss this mostly in categorical terms like diagnoses but also sort of acknowledge that measures symptom burden relate to functional outcomes as well. The authors describe both co morbidities impacting ‘quality of life’ QoL which includes a host of things peer and family relations, academic performance, etc. A lot of the described work is cross sectional so the authors then set out to longitudinally test the impact of externalizing and internalizing comorbs on functional outcomes like QoL in individuals with ADHD. Although the authors note unique problems associated with each comorb (ex vs, in) their focus seems to be more on just ADHD vs. ADHD + ex and/or in and less about ex vs. in impacts.
Methods: Participants - participants were recruited from two larger studies of ADHD. Aged 5-13. ADHD symptom burden reported by parent was used to confirm ADHD status. ADISC was used to identify diagnostic status. Participants were split into one of four categories, ADHD alone, ADHD + INT such as Anxiety Disorder, Social Phobia, Specific Phobia, Separation Anxiety Disorder, Panic Disorder, Obsessive–Compulsive Disorder, Posttraumatic Stress Disorder, ADHD + EXT such as ODD or CD or a comorbid combination of all three Measures - Parent reported ADHD symptom burden, socio-demographic measures, peer functioning from the strengths and weaknesses questionnaire. Child functioning, psychosocial quality of life, parent mental health, and family quality of life measure were collected at baseline and 12 month follow up except for family quality of life. Analysis - ANOVAs were used to test for differences at baseline while HLM was used to test for longitudinal effects.
Results: Internalizing and externalizing comorbidities were common in the sample with externalizing comorbidies being slightly higher. At baseline there were differences between children with both comorbs and hose with just ADHD however there were smaller effects seen for externalizing alone and none for internalizing alone. In terms of the longitudinal models,children with externalizing and co-occurring comorbidities had increased peer problems. Children with co-occurring comorbidities had increased daily functioning difficulties and poorer quality of life, compared to children with ADHD alone. Children with externalizing comorbidities alone also had increased daily functioning difficulties, compared to children with ADHD alone. All three groups had higher reports impact on family and activites, and all but INT reported impact on family emotion. ASD diagnosis was also independently associated with increased parent-reported peer problems at 12 months. Children with co-occurring comorbidities continued had increased parent-reported peer problems.
Thoughts: Nothing hugely shocking maybe, except it seems like internalizing comorbidities alone has less impact HOWEVER is that because this is all parent report? Highest burden tracking with most comorbidities does make sense though.