Shubhangi Parkar1, Karishma Rupani1*, Gaurav Malhotra2, Natasha Kate3, Trupti Upadhye Bannor2
Background: Individuals with suicidal behaviors are increasingly recognized as having impairments in brain metabolism. However what differentiates those who attempt suicide while having diagnosable depression versus those who attempt suicide without depression, in terms of neurobiology is still largely unknown.
Aims: Using the F-18 FDG brain positron emission tomography to:
1. To evaluate differences in resting Cerebral Glucose Metabolism (rCMglu) between depressed and non-depressed suicidal subjects.
2. To translate a suicide attempt, which is a behavioral construct (NSSI or otherwise) into neurobiological constructs.
Methods: Patients with suicide attempt with diagnosable Depression and those with suicide attempt without diagnosable depression (NSSI) were included. Brain metabolism was assessed using [18F] Fluoro Deoxy-Glucose Positron Emission Tomography (FDG-PET). The brain PET scans were analyzed using the NEUROQ software.
Results: Of 33 subjects, eighteen had major depressive disorder. Comparison using brain FDG PET scan showed hypermetabolism in the components of the Default Mode Network (self-referential ruminations), the Salience network (modulating emotional behaviour) and hypometabolism in the Dorso lateral prefrontal cortex (cognition, executive functioning), visual association (visual memory) in those with Major Depressive disorder only and not in those with Non Suicidal Self Injury (NSSI).
Conclusion: Significant differences exist in rCMglu of suicidal individuals with and without depression. Understanding these would help us formulate treatment strategies. Our study shows that even those individuals who may not fulfil DSM or ICD criteria for Major Depressive disorder should be treated as a case of MDD if they have negative self-referential ruminations, impaired information processing and cognition.