Hot Suicidal Ideation in MDD Tied to Reduced Brain Volumes

TOPLINEA retrospective structural MRI study found that "hot" or affectively driven suicidal ideation (SI) among patients with major depressive disorder (MDD) was associated with reduced thalamo-pallidal volumes. No significant association between "cold" or deliberate SI and reduced thalamo-pallidal volumes was observed.METHODOLOGYResearchers retrospectively analysed structural MRI data from 263 individuals with MDD experiencing a current major depressive episode at Henri Laborit Hospital in Poitiers, France, between 2014 and 2025. Participants were categorised into three groups based on the Montgomery-Åsberg Depression Rating Scale suicide item: those with no SI (n = 207), those with hot SI (n = 49), and those with cold SI (n = 7). A thalamo-pallidal composite score was computed from z-scores of bilateral thalamus and right pallidum volumes, with the regions defined according to Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) findings associated with suicide attempt. Researchers analysed potential associations between ideation subtypes and brain volumes, adjusting for age, sex, intracranial volume, depression severity measured using the Beck Depression Inventory-Short Form, and history of suicide attempt. The dorsolateral prefrontal cortex (DLPFC) volume was examined as a specificity control to determine whether associations were specific to subcortical regions rather than a reflection of generalised volumetric alterations. TAKEAWAYParticipants with hot SI had reduced thalamo-pallidal volumes compared with those without SI (regression coefficient, -0.57; P = .034); by contrast, thalamo-pallidal volumes did not differ significantly between participants with cold SI and those without SI. No significant associations were observed between the SI subtypes and the DLPFC volume, supporting the specificity of the findings to subcortical regions. The association between hot SI and reduced thalamo-pallidal volumes remained significant after controlling for the DLPFC composite index (regression coefficient, -0.58; P = .031), indicating that the association was independent of broader cortical volumetric variations. Individual region analyses showed consistently negative associations for hot SI across the left thalamus, right thalamus, and right pallidum; however, no statistically significant association was observed for any individual region. IN PRACTICE"Our findings suggest that distinct forms of suicidal ideation may show different neurobiological associations. Specifically, the ENIGMA-defined thalamo-pallidal signature of suicide attempt was observed in hot, but not cold, suicidal ideation," the authors wrote. "These results illustrate how refining the phenotypic characterization of suicidal ideation may reveal neurobiological associations that remain undetected when suicidal ideation is treated as a unitary construct," they added.SOURCEThe study was led by Armand Chatard, Centre Hospitalier Laborit, Poitiers, France. It was published online on September 8 in the Journal of Affective Disorders.LIMITATIONSThe study was limited by its retrospective, cross-sectional design, a limited number of participants with cold SI, and its reliance on a single clinician-rated MADRS item rather than a dedicated multidimensional instrument to derive SI subtypes.DISCLOSURESThe study was supported by recurrent internal institutional funds. The authors reported having no conflicts of interest. This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.