Associations of glymphatic system dysfunction and personality traits alterations in bipolar depression with suicidal...

It remains unclear whether individuals with bipolar disorder (BD) with suicidal attempt (SA) exhibit glymphatic dysfunction, or how such dysfunction may relate to personality traits.

In this study, magnetic resonance imaging (MRI) was used to evaluate glymphatic function by calculating multiple indices, including the diffusion tensor imaging along the perivascular space (DTI-ALPS) index, free-water (FW), perivascular space volume (PVS), and choroid plexus volume (CP), in 37 BD individuals with SA, 35 BD individuals without SA (NSA), and 35 healthy controls (HCs). Among BD individuals, SA was assessed using Beck Scale for Suicidal Ideation (SSI-Beck), and personality traits were evaluated via the Minnesota Multiphasic Personality Inventory-2 (MMPI-2).

BD patients with SA scored higher on MMPI-2 for Hypochondriasis, Depression, and Schizophrenia than NSA and HCs. Furthermore, BD patients with SA exhibited lower ALPS index and higher FW than HCs, but no significant differences in ALPS index and FW between SA-NSA or NSA-HCs groups, nor in CP and PVS among three groups. In BD with SA, Schizophrenia scores showed a negative correlation with the right ALPS index, whereas Paranoia and Hypochondria scores were positively correlated with FW. Multivariate regression analysis revealed that the interaction between FW and Psychopathic Deviate independently predicted SSI-Beck scores in BD with SA.

This study demonstrates that glymphatic dysfunction and maladaptive personality traits in BD with SA may interact to exacerbate suicidal tendencies, suggesting glymphatic - targeting therapies as a potential strategy to reduce suicide risk.