Factors associated with anxiety disorder comorbidity

Abstract

Background: Anxiety and depressive disorders often co-occur and the order of their emergence may be associated with different clinical outcomes. However, minimal research has been conducted on anxiety-anxiety comorbidity. This study examined factors associated with anxiety comorbidity and anxiety-MDD temporal sequence.

Methods: Online, self-report data were collected from the UK-based GLAD and COPING NBR cohorts (N = 38,775). Logistic regression analyses compared differences in sociodemographic, trauma, and clinical factors between single anxiety, anxiety-anxiety comorbidity, anxiety-MDD (major depressive disorder) comorbidity, and MDD-only. Additionally, anxiety-first and MDD-first anxiety-MDD were compared. Differences in familial risk were assessed in those participants with self-reported family history or genotype data.

Results: Anxiety-anxiety and anxiety-MDD had higher rates of self-reported anxiety or depressive disorder diagnoses, younger age of onset, and higher recurrence than single anxiety. Anxiety-MDD displayed greater clinical severity/complexity than MDD only. Anxiety-anxiety had more severe current anxiety symptoms, less severe current depressive symptoms, and reduced likelihood of self-reporting an anxiety/depressive disorder diagnosis than anxiety-MDD. Anxiety-first anxiety-MDD had a younger age of onset, more severe anxiety symptoms, and less likelihood of self-reporting a diagnosis than MDD-first. Minimal differences in familial risk were found.

Limitations: Self-report, retrospective measures may introduce recall bias. The familial risk analyses were likely underpowered.

Conclusions: Anxiety-anxiety comorbidity displayed a similarly severe and complex profile of symptoms as anxiety-MDD but distinct features. For anxiety-MDD, first-onset anxiety had an earlier age of onset and greater severity than MDD-first. Anxiety disorders and comorbidity warrant further investigation and attention in research and practice.

Keywords: Affective disorders; Anxiety disorders; Comorbidity; Depressive disorders; Polygenic risk score.

Fig. 1

Frequencies of lifetime major depressive disorder, any anxiety, and the anxiety disorders for the full sample and by cohort. The bars represent the proportion (%) of the full sample (N = 38,775), GLAD (N = 35,210), or COPING NBR (N = 3565). *“Any anxiety” includes participants with at least one anxiety disorder (GAD, specific phobia, social anxiety disorder, panic disorder, and/or agoraphobia) on the symptom-based measure. Abbreviations: GLAD = Genetics Links to Anxiety and Depression; COPING NBR = COVID-19 Psychiatry and Neurological Genetics NIHR BioResource; MDD = major depressive disorder; GAD = generalised anxiety disorder

Fig. 2

Descriptives of sociodemographic, trauma, and clinical factors by comorbidity group.

Fig. 3

Descriptives by temporal sequence. The descriptives for each of the sociodemographic, trauma, and clinical factors included in the logistic regression model are displayed by anxiety-MDD temporal sequence. Anxiety-first (N = 9838) is displayed in yellow, and MDD-first (N = 8845) is displayed in blue. The units for the graphs vary depending on the variables. Graph A presents the mean age and age of onset (in years) and the mean number of episodes for recurrence. Graph B displays the proportion (%) of participants in the comorbidity groups who experienced each type of trauma. Graph C shows the mean scores for current anxiety (GAD7) and current depressive (PHQ9) symptoms. Graph D presents the proportion (%) of participants who responded positively to each variable (e.g., for “Sex: Female”, the bars indicate the percent of Female participants). Abbreviations: MDD = major depressive disorder; GAD7 = 7-item generalised anxiety disorder assessment; PHQ9 = 9-item patient health questionnaire