IED Linked With Multiple Psychiatric, Neurologic Comorbidities
Intermittent explosive disorder (IED) was found to have many comorbidities, including substance use disorder, neurodegenerative diseases, sleep disorders, and many somatic diseases, according to a recent cohort study published in JAMA Psychiatry.
“These findings highlight the extensive comorbidities between IED and psychiatric, neurological, and somatic disorders,” authors noted, “emphasizing the need for integrated diagnostic and treatment approaches addressing both psychological and physical health aspects of IED.”
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Researchers used electronic medical records from the TriNetX Research Network (as of January 31, 2024) to analyze matched groups of patients with and without IED. The mean time from the first to last recorded visit was 4.8 years. The primary exposure was a lifetime diagnosis of IED, and the main outcomes included diagnostic categories based on the International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM). Cox proportional hazard models were used to estimate probabilities of acquiring other diagnoses, focusing on the numbers, proportions, and adjusted hazard ratios (HRs) associated with IED.
The study included 30,357 individuals with IED and 30,357 demographically matched controls, with both groups being 70% male and having a mean age of 26 years at the first visit. Although IED represented only 0.03% of the total patient population, it was significantly associated with psychiatric, neurological, and somatic comorbidities. A total of 95.7% of individuals with IED had another psychiatric diagnosis, with hazard ratios (HRs) ranging from 2.1 for substance use disorder to 76.6 for adult personality and behavior disorders (excluding IED). Neurological conditions such as neurodegenerative diseases (HR, 5.0), epilepsy (HR, 4.9), and movement disorders (HR, 3.1), as well as somatic conditions like obesity (HR, 1.6), hyperlipidemia (HR, 1.5), and hypertension (HR, 1.6), were also significantly linked to IED.
Authors noted that the results of this study should be interpreted with several limitations in mind. Reliance on medical records may have introduced sampling biases compared to structured interviews, and the low prevalence and high psychiatric comorbidity of IED raise concerns about diagnostic accuracy in clinical practice. Additionally, the low prevalence of IED may have led to some cases being misclassified in the non-IED cohort, potentially diluting the findings, while diagnosed cases may reflect more severe presentations, exaggerating associations with comorbidities.
“We believe that impulsive aggression, defined with or without exclusion criteria for other psychiatric conditions, and diagnosed liberally or as a last resort, will remain robustly comorbid with a wide variety of psychiatric and other medical conditions,” authors concluded. “This hypothesis should be confirmed or denied by future research.”
