Measurement of hypothalamus and amygdala volume change in patients with conversion disorder

Introduction and Objective: Conversion disorder is a condition associated with psychological stressors that disrupts voluntary motor and sensory functions, leading to functional loss, impairment, or exaggeration, mimicking neurological disorders and medical conditions without an organic basis. The absence of objective criteria, specific symptoms, signs, or laboratory findings for diagnosing this illness adversely affects the process of diagnosing and treating individuals. Due to the limitations of research in this field, the neurobiology of conversion disorder has not yet been clearly elucidated. The aim of our study is to contribute to the neurobiology of conversion disorder by evaluating whether there are differences in the volume of the hypothalamus and amygdala between patients with conversion disorder and a control group. Method: The study included a patient group diagnosed with conversion disorder at the Adıyaman Education and Research Hospital Psychiatry Outpatient Clinic, along with a healthy control group. Sociodemographic and clinical data forms were administered to the participants, and the Beck Anxiety Scale and Beck Depression Scale were administered to the patient group. After a neurological and mental status examination conducted by the thesis researcher, brain MRI scans of the patients were performed in the Department of Radiology. Results: The study included 28 patients (22 females, 6 males) and 33 healthy controls (28 females, 5 males). 78.8% of the patients were female, and their family income levels were mostly lower than expenses, with low education levels. The patient group had lower educational and employment status compared to the control group. 53.6% of the patient group had a history of adverse childhood experiences, which was significantly higher compared to the control group (15.2%) (p<0.001). Four patients received inpatient treatment in the vii psychiatric ward. The proportion of patients with suicidal ideation was higher in the patient group (53.6%) compared to the control group (3.0%), and this difference was statistically significant (p<0.001). When examining suicide attempts, it was observed that 32.1% of the patient group had a history of previous suicide attempts. However, none of the individuals in the control group had a history of suicide attempts. This difference was statistically significant and indicated a higher tendency towards suicide in the patient group. In the patient group, it was observed that the sizes of the right and left hypothalamus were greater compared to the control group. A statistically significant difference was found between the two groups in terms of the volume of the right hypothalamus (p=0.005). Similarly, a significant difference was also found between the two groups in the size of the left hypothalamus (p=0.019). When examining the sizes of the amygdala, it was found that the volume of both the right and left amygdala was larger compared to the control group. A statistically significant difference was found between the two groups in terms of the volume of the right amygdala (p=0.001). Similarly, a significant difference was also found between the two groups in the size of the left amygdala (p=0.001). Conclusion: In the patient group, bilateral hypothalamus and bilateral amygdala volumes were found to be larger compared to the control group. Our finding, supported by emerging evidence suggesting that stress response can lead to structural and functional changes in the brain, proposes that the hypothalamus and amygdala may play a crucial role in conversion disorder. Due to the limitations of studies conducted in the field of conversion disorder and the incomplete understanding of its neurobiology, further neuroimaging studies should be conducted to validate the obtained data.