Indian Journal of Psychological Medicine

LETTERS TO EDITOR
Year
: 2018  |  Volume : 40  |  Issue : 4  |  Page : 393--394

Comments on “efficacy of transcranial direct current stimulation in the treatment: Resistant patients who suffer from severe obsessive-compulsive disorder”


Satish Suhas1, Girish Banwari2, Harish M Tharayil3, Sagar Karia4, Migita M D'Cruz1, Sachin Nagendrappa1, Chittaranjan Andrade5,  
1 Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
2 Department of Psychiatry, Dr. Ismail Polyclinic and National Medical Center, Dubai, UAE
3 Department of Psychiatry, Government Medical College, Kozhikode, Kerala, India
4 Department of Psychiatry, Lokmanya Tilak Municipal Medical College and General Hospital, Mumbai, Maharastra, India
5 Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Satish Suhas
Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru - 560 029, Karnataka
India




How to cite this article:
Suhas S, Banwari G, Tharayil HM, Karia S, D'Cruz MM, Nagendrappa S, Andrade C. Comments on “efficacy of transcranial direct current stimulation in the treatment: Resistant patients who suffer from severe obsessive-compulsive disorder”.Indian J Psychol Med 2018;40:393-394


How to cite this URL:
Suhas S, Banwari G, Tharayil HM, Karia S, D'Cruz MM, Nagendrappa S, Andrade C. Comments on “efficacy of transcranial direct current stimulation in the treatment: Resistant patients who suffer from severe obsessive-compulsive disorder”. Indian J Psychol Med [serial online] 2018 [cited 2019 Oct 21 ];40:393-394
Available from: http://www.ijpm.info/text.asp?2018/40/4/393/234789


Full Text



Sir,

Najafi et al.[1] described a nonblind, uncontrolled evaluation of 15 once daily, 5 per week sessions of transcranial direct current stimulation (tDCS) in 42 patients with severe, treatment-resistant obsessive–compulsive disorder (OCD). We urge that readers view their results with considerable caution.

The authors did not provide a complete operational definition of treatment resistance. They did not describe the clinical characteristics of the sample. They did not provide information about concurrent medications during and after the tDCS course. Their description of electrode positioning in the 10–20 electroencephalography system does not correspond with the anatomical sites they named. Their description of the inferential statistical procedures suggests that they had difficulties with interpreting the analysis. Unusually, there were no dropouts from among 42 patients in a 3-week trial with daily sessions and a 3-month follow-up.

Finally, they obtained results that are at considerable variance with clinical experience. OCD is hard to treat, and an adequate clinical trial is suggested to require 2–3 months; attenuation of OCD ratings by 25%–35% is commonly set as the threshold for response.[2],[3],[4] Yet, Najafi et al.[1] found that the sample as a whole showed >50% response in just 2 weeks and >75% improvement at a 3-month follow-up. In fact, at the final assessments, the patients were almost in remission, a rare event in OCD research.[2],[3],[4]

Such dramatic outcomes are especially difficult to understand because tDCS is a mild treatment that does not stimulate or inhibit the underlying cerebral cortex; it is merely a neuromodulator that facilitates or inhibits depolarization of the underlying cortex.[5],[6] In this context, it must be recognized that OCD is believed to more involve not the cortex but subcortical structures such as the thalamus and basal ganglia and associated subcortical neurocircuits;[7],[8] these are poorly targeted by tDCS.[5],[6]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Najafi K, Fakour Y, Zarrabi H, Heidarzadeh A, Khalkhali M, Yeganeh T, et al. Efficacy of transcranial direct current stimulation in the treatment: Resistant patients who suffer from severe obsessive-compulsive disorder. Indian J Psychol Med 2017;39:573-8.
2Soomro GM, Altman D, Rajagopal S, Oakley-Browne M. Selective serotonin re-uptake inhibitors (SSRIs) versus placebo for obsessive compulsive disorder (OCD). Cochrane Database Syst Rev 2008;CD001765.
3Pittenger C, Bloch MH. Pharmacological treatment of obsessive-compulsive disorder. Psychiatr Clin North Am 2014;37:375-91.
4Hirschtritt ME, Bloch MH, Mathews CA. Obsessive-compulsive disorder: Advances in diagnosis and treatment. JAMA 2017;317:1358-67.
5Nitsche MA, Cohen LG, Wassermann EM, Priori A, Lang N, Antal A, et al. Transcranial direct current stimulation: State of the art 2008. Brain Stimul 2008;1:206-23.
6Brunoni AR, Nitsche MA, Bolognini N, Bikson M, Wagner T, Merabet L, et al. Clinical research with transcranial direct current stimulation (tDCS): Challenges and future directions. Brain Stimul 2012;5:175-95.
7Mulders AE, Plantinga BR, Schruers K, Duits A, Janssen ML, Ackermans L, et al. Deep brain stimulation of the subthalamic nucleus in obsessive-compulsive disorder: Neuroanatomical and pathophysiological considerations. Eur Neuropsychopharmacol 2016;26:1909-19.
8Gürsel DA, Avram M, Sorg C, Brandl F, Koch K. Frontoparietal areas link impairments of large-scale intrinsic brain networks with aberrant fronto-striatal interactions in OCD: A meta-analysis of resting-state functional connectivity. Neurosci Biobehav Rev 2018;87:151-60.