Attentional Networks in Co-occurring Generalized Anxiety Disorder and Major Depression Disorder: Towards a Staging Approach to the Executive Control Deficits

Abstract

Background. Major Depression Disorder (MDD) and Generalized Anxiety Disorder (GAD) often co-occur, but the neurocognitive mechanisms of this co-occurrence remain unknown. Prominent views have pointed to attentional processes as potent mechanisms at play in MDD and GAD, respectively. Yet uncertainty remains regarding the very nature of attentional impairments in patients with co-occurring MDD and GAD. Methods. Inspired by contemporary models of attentional networks, we examined the integrity of the three main attentional networks, namely the alerting, orienting, and executive control networks, in patients with co-occurring MDD and GAD (n = 30), MDD only (n = 30), GAD only (n = 30), or neither MDD or GAD (n = 30).Results. Patients with co-occurring MDD and GAD exhibited more severe impairments in the executive control network than those with only one of the disorders. There were no differences between the executive control networks of patients with solely MDD or solely GAD, but both groups showed significantly more severe impairment than those without either MDD and GAD. Limitations. The cross-sectional study design precludes strong inference regarding the cause-effect relationship between the executive control network and the co-occurrence of MDD and GAD. Conclusions. Our findings align with a longstanding staging approach to comorbidity whereby, via synergistic effects, co-occurring disorders yield greater damage than the sum of each disorder. Here, for the first time, we extended this approach to the executive control network of attention in the context of the co-occurrence between MDD and GAD.