Significant Decrease in Hippocampus and Amygdala Mean Diffusivity in Treatment-Resistant Depression Patients Who Respond to Electroconvulsive Therapy.

Introduction: The hippocampus plays a key role in depressive disorder, and the amygdala is involved in depressive disorder through the key role that it plays in emotional regulation. Electroconvulsive therapy (ECT) may alter the microstructure of these two regions. Since mean diffusivity (MD), is known to be an indirect marker of microstructural integrity and can be derived from diffusion tensor imaging (DTI) scans, we aim to test the hypothesis that treatment-resistant depression (TRD) patients undergoing bilateral (BL) ECT exhibit a decrease of MD in their hippocampus and amygdala. Methods: Patients, between 50 and 70 years of age, diagnosed with TRD were recruited from the University Hospital of Toulouse and assessed clinically (Hamilton Depression Rating Scale, HAM-D) and by DTI scans at three time points: baseline, V2 (during treatment), and V3 within 1 week of completing ECT. Results: We included 15 patients, who were all responders. The left and right hippocampi and the left amygdala showed a significant decrease in MD at V3, compared to baseline [respectively: ß = -2.78, t = -1.97, p = 0.04; ß = -2.56, t = -2, p = 0.04; ß = -2.5, t = -2.3, p = 0.04, false discovery rate (FDR) corrected]. MD did not decrease in the right amygdala. Only the left amygdala was significantly associated with a reduction in HAM-D (ρ = 0.55, p = 0.049, FDR corrected). Conclusion: MD is an indirect microstructural integrity marker, which decreases in the hippocampus and the left amygdala, during BL ECT in TRD populations. This could be interpreted as a normalization of microstructural integrity in these structures.

Memory impairment following intentional self-poisoning with benzodiazepines: Should we pay more attention to attention?

STUDY HYPOTHESIS: In cases where patients attempt suicide through intentional self-poisoning, they often ingest drugs such as benzodiazepines that alter the central nervous system and memory. This is problematic, given that experts recommend the recovery of a patient's cognitive capacity before any psychiatric assessment is conducted. A previous pilot study by our group showed that cognitive tests focusing on attention are the most valuable when it comes to determining whether sufficient cognitive recovery has occurred to ensure that patients will remember the assessment after intentional self-poisoning with benzodiazepines. The main aim of our study was to determine cognitive predictors of the recall of the psychiatric assessment after a suicide attempt. The second aim was to determine the threshold for episodic memory. METHODS: We recruited 97 patients admitted for intentional self-poisoning. At the time of the psychiatric assessments, we quantified plasma benzodiazepine levels and performed a cognitive assessment. We then used a linear regression model to identify the associations in a control and a benzodiazepine group between cognitive functions and episodic memory scores obtained 24 hours after psychiatric assessment. RESULTS: Our model accounted for 28% and 37%, respectively, of the variance in memory in the control and benzodiazepine groups. The most significant correlations were found for the Wechsler Adult Intelligence Scale coding test in both groups. In the control group, tests such as visual and verbal memory were also associated with recall. CONCLUSIONS: Benzodiazepines particularly affect memory by impairing what is remembered of attentional tests. These are, however, the most suitable cognitive tests for predicting recall of the memory assessment.

Grey Matter changes in treatment-resistant depression during electroconvulsive therapy.

INTRODUCTION: 20-30% of depressed patients experience Treatment Resistant Depression (TRD). Electroconvulsive Therapy (ECT) remains the treatment of choice for TRD. However, the exact mechanism of ECT remains unclear. We aim to assess grey matter changes in patients with TRD undergoing bilateral ECT treatment at different points during and after treatment. METHODS: Patients are recruited at the University Hospital of Toulouse. Eligibility criteria include a diagnosis of TRD and an age between 50 and 70 years old. Patients received clinical assessments (Hamilton Depression Rating Scale) and structural scans (MRI) at three points: baseline (within 48 h before the first ECT); V2 (after the first ECT considered effective); and V3 (within 1 week of completing ECT). RESULTS: At baseline, controls had significantly higher cortical thickness than patients in the fusiform gyrus, the inferior, middle and superior temporal gyrus, the parahippocampal gyrus and the transverse temporal gyrus (respectively: t(35)=2.7, p = 0.02; t(35)=2.89, p = 0.017; t(35)=3.1, p = 0.015; t(35)=3.6, p = 0.009; t(35)=2.37, p = 0.031; t(35)=2.46, p = 0.03). This difference was no longer significant after ECT. We showed an increase in cortical thickness in superior temporal gyrus between (i) baseline and V3 (t(62)=-3.43 p = 0.009) and (ii) V2 and V3 (t(62)=-3.42 p = 0.009). We showed an increase in hippocampal volume between (i) baseline and V3 (t(62)=-5.23 p < 0.001) and (ii) V2 and V3 (t(62)=-5.3 p < 0.001). CONCLUSION: We highlight that there are grey matter changes during ECT treatment in a population with TRD compared to a healthy control population. These changes seem to occur after several rounds of ECT.

Cluster Headache in Subjects With Substance Use Disorder: A Case Series and a Review of the Literature.

OBJECTIVE: To describe a case series of 7 patients presenting cluster headache (CH) criteria and a substance use disorder, reported to a French Addictovigilance center. Then, to assess clinical, pharmacological, and neurobiological linkages between substance use and CH onset. BACKGROUND: CH patients are presenting a higher prevalence of comorbidities, among which the use of psychoactive substances, licit or illicit, have been explored by a few authors. Recently, 3 cases of CH in patients seen in the hospital-based addiction care center have been reported to the Toulouse addictovigilance center. METHODS: Other cases have been identified in the same tertiary hospital after a collaborative investigation done with the departments of neurology and psychiatry and included in the case series. A narrative review was performed to assess the potential of psychoactive substance consumption to induce or facilitate CH. RESULTS: From 2016 to 2018, 6 males and 1 female aged between 26 and 54 years old, presenting CH criteria and a substance use disorder, were included in our case series. Among substances used, there are: (1) daily use of tobacco and alcohol in 5/7 subjects; (2) daily or almost daily use of cocaine in 5/7 subjects; (3) regular use of cannabis before attacks beginning in 4/7 subjects; and (4) opioids, as a substitutive medication or abused, in 5/7 subjects. The intranasal route administration is reported by all the subjects and precedes the beginning of attacks for 5/7 subjects. CONCLUSIONS: We have found a CH prevalence of 0.9% in our studied population, while it is estimated at 0.1% in the general population. The coexistence of cluster headache and addiction behaviors reflects possible common neurobiological pathways, which would include the hypothalamus. Research could be conducted on the potential of hypothalamic therapeutic targets.