Effects of transcranial magnetic stimulation on anhedonia in treatment resistant major depressive disorder.

BACKGROUND: Anhedonia is one of the defining features of depression but it remains difficult to target and treat. Transcranial magnetic stimulation (TMS) is a proven treatment for depression, but its effects on anhedonia and whether anhedonia can be used as a predictive biomarker of response is not well known. METHODS: Snaith-Hamilton Pleasure Scale was administered to patients with depression before and after a standard course of TMS in a naturalistic outpatient setting. RESULTS: 144 patients were analyzed. There was an overall significant improvement in anhedonia from pre- to post-treatment (7.69 ± 3.88 vs. 2.96 ± 3.45; p < .001). Significant correlations between improvements in anhedonia and other depressive symptoms were present (r = 0.55, p < .001). Logistic regression revealed that baseline anhedonia severity was not a significant predictor of clinical outcome. CONCLUSION: This is the first large, naturalistic study examining the effects of standard, non-research TMS on anhedonia. Among depressed patients, TMS resulted in significant improvements in anhedonia. Patients with severe baseline anhedonia had an equal chance of achieving clinical response/remission. Patients with anhedonia should not be excluded from treatment if they are safe for outpatient care and otherwise appropriate candidates for treatment.

Peripheral vascular endothelial growth factor changes after transcranial magnetic stimulation in treatment-resistant depression.

OBJECTIVES: To determine if vascular endothelial growth factor (VEGF) changes with transcranial magnetic stimulation (TMS) in treatment-resistant major depressive disorder (MDD). METHODS: Serum from a naturalistic population of 15 patients with MDD was collected at baseline and after standard TMS treatment. VEGF concentration was determined via ELISA. Inventory of Depressive Symptomatology Self Report and Patient Health Questionnaire were used as a measure of depression symptom severity, clinical response and remission. Mann-Whitney U and Kendall's Tau Correlation were used for continuous variables. RESULTS: VEGF increased from pre- to post-TMS (+30.3%) in remitters whereas VEGF decreased in non-remitters (-9.87%) (P < 0.05). This same pattern was observed when comparing mean %change in VEGF between responders (+14.7%) and non-responders (-14.9%) (P = 0.054). Correlation was present between change in VEGF concentration (baseline to post) and change in Inventory of Depressive Symptomatology-Self Report at Tx30 (r = -0.371, P < 0.054), reflecting greater increases in VEGF linked to greater improvement in depressive symptoms following the standard 6-week course of TMS. CONCLUSION: Patients with a successful treatment with TMS had significantly greater increase in VEGF from baseline to after treatment compared to non-responders/non-remitters and a larger increase in VEGF was associated with greater improvement in depressive symptoms after TMS. This is the first report examining VEGF levels in depressed patients receiving TMS. This study provides correlative data supporting further investigation into VEGF's role as an important mediator in the processes underpinning TMS' antidepressant effects and as a potential biomarker of clinical outcomes.