Affective temperamental profiles influence suicide risk in mood disorders
MedWire News: The temperament profiles of patients with major affective disorders have a profound influence on both hopelessness and suicidal behavior, in a relationship that is mediated by white matter hyperintensities (WMHs), study results show.
In particular, a profile marked by high dysthymia and low hyperthymia "may represent a specific sub-group at risk for highly lethal suicide attempts," say Gianluca Serafini (University of Rome, Italy) and colleagues in the Journal of Affective Disorders.
Mood disorders can range from sub-threshold affective temperament traits (measured by scales like the TEMPS-A or more traditional NEO Five Factor Inventory) through minor and major mood disorders to severe affective psychosis.
Mood regulation depends on the complex extensive connections between the prefrontal cortex, amygdala-hippocampus complex, thalamus, and basal ganglia.
Of particular interest are WMHs, which appear as peak signals on T2-weighted magnetic resonance images (MRI) and represent ependymal loss and differing degrees of myelination in the brain.
"To our current knowledge, there are no data linking white matter abnormalities, affective temperaments, and suicidal behavior in mood disorders," Serafini et al comment.
To address this, they recruited 247 patients with major affective disorders of whom 185 (75%) had bipolar disorder and 62 (25%) had major depressive disorder.
Patients were assessed with magnetic resonance imaging (MRI), Mini International Neuropsychiatric Interview (MINI; a measure of sucidaility), the Beck Hopelessness Scale (BHS), and the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-A).
Patients with a temperament profile characterized by high scores of dysthymia, cyclothymia, anxiety, and irritability, and lower scores on hyperthymia showed worse outcomes than their peers with the opposite temperament profile, that is, higher scores on hyperthymia and lower scores of dysthymia, cyclothymia, and anxiety.
Specifically, the former group showed higher BHS scores (BHS≥9=77% versus 52%), more WMH (46% vs 29%), higher MINI suicidal risk (54% vs 42%), and more recent suicide attempts (24% vs 14%) than the latter group.
Discussing the findings, the researchers note that recent genetic studies have shown that the short allele of the serotonin transporter gene is significantly related to depressive, cyclothymic, irritable and anxious temperaments but not to the hyperthymic temperament
Thus, they speculate that "genetic factors contribute to the dysthymic temperament and this relationship is at least partially mediated by development of WMHs."
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By Andrew Czyzewski