Abstract
Background/Objectives: Generalized anxiety disorder (GAD) is one of the most commonly diagnosed anxiety disorders in primary care. The global lifetime prevalence of GAD is estimated at 3.7%, ranging from 1.6% in low-income countries to 5.0% in high-income countries, underscoring its widespread impact. Given the frequent co-occurrence of GAD with obesity, this association has important clinical implications, particularly for screening, prevention, and treatment strategies. The aim of this review is to identify potential biological mechanisms linking obesity and GAD, summarize the current state of knowledge in this area, and highlight existing research gaps, as well as directions for future research. Methods: This narrative review is based on the literature published between 2015 and 2025 concerning the co-occurrence of GAD and obesity, with a focus on potential shared mechanisms including HPA axis dysregulation, chronic inflammation, oxidative stress, insulin resistance, gut-brain axis and microbiota dysbiosis, sleep disturbance, and maladaptive eating behaviors. Results/Conclusions: A growing body of evidence suggests an important, albeit still ambiguously defined, relationship between obesity and GAD. GAD and obesity may reinforce each other, leading to a mutually reinforcing relationship. Despite growing interest, high-quality prospective and interventional studies focusing specifically on GAD are lacking. A potentially effective therapeutic approach should be integrated and multidisciplinary, combining psychological, pharmacological, and lifestyle interventions. It may also be beneficial for clinicians to consider routine assessment of anxiety in patients with obesity and, conversely, to monitor metabolic risk in individuals with GAD. Such an approach, targeting both mental and metabolic domains, holds promise for improving outcomes.