Journal: Brain Stimulation (2015)
Authors: Duffy W, Choudhry Z, Rajamani M, Nathan R, Siddiqui W, Waris M
Background:
A positive correlation between caffeine consumption and depression was recently reported. Biologically, caffeine inhibits adenosine A1 and A2A receptors. Researchers link A2A receptors with depression pathogenesis. They suggest a tight interaction between A2A receptors and Trk-B receptors which are upstream of Brain-Derived Neurotrophic Factor (BDNF). Thus, it is possible to infer that caffeine usage may modulate deep Transcranial Magnetic Stimulation (dTMS) treatment outcomes in patients with Major depressive disorder (MDD).
Objective:
To explore the effect of caffeine on modulating dTMS outcomes.
Methods:
Fifty-seven patients (68% female) with MDD, ages 24-67 years (mean=42.50), previously failing 0-8 MDD medication regimens (mean=4.2) received dTMS. Amongst these, forty-two (74%) reported habitual caffeine usage. Depressive symptom severity (DSS) was assessed using the Zung Self-Rating Depression Scale (ZSRDS) at baseline and every 5 treatments subsequently. Patients received an acute phase dTMS treatment (20 sessions), after which 6 patients discontinued treatment and did not receive further maintenance treatment. The effect of caffeine usage, on dTMS efficacy was evaluated using Repeated Measure ANOVA to contrast baseline with post-acute and maintenance treatment paradigms.
Results:
All patients reported significantly reduced DSS after dTMS treatment assessed by ZSRDS. However, a significant effect of caffeine usage was observed on dTMS treatment post-maintenance phase (p=0.021). Specifically, caffeine users reported greater decrease in DSS scores in post-maintenance (30 sessions) treatment.
Conclusions:
These results suggest that patients who are caffeine users report greater decrease in DSS scores post-maintenance treatment. However, further research is warranted to reach firmer conclusions.
