What is Depression?
Episodes of feeling blue and unhappy occur normally in life of every person. Their severity and duration depend on the reason that provoked bad feelings, as well as on the emotional vulnerability of each individual person. However, persons suffering from depression feel this way more frequently, their episodes last longer and may occur for no particular reason. According to World Health Organization (WHO), depression is the leading cause of disability affecting 350 million persons worldwide.
The main symptoms include overwhelming feelings of pessimism, hopelessness, fatigue, irritability, restlessness, sadness, and helplessness. These persons often have difficulties to concentrate, interact with other people, and either insomnia or excessive sleeping pattern. Symptoms may be from mild to very severe, leading even to suicidal thoughts.
Diagnosing Depression
If you notice some of the above symptoms, you should refer to your psychiatrist. Diagnosis of depression is not easy to make, because there are many different types and modalities of this disorder, and the spectrum of signs and symptoms is very wide. Psychiatrists use series of questions about various aspects of your life to identify elements of depression. Sometimes, more than one visit is needed in order to establish the diagnosis. After assessing the assessment, your psychiatrist will propose the appropriate treatment plan, according to type and severity of depression.
Treatment Options
Common treatment options for depression include medication therapy, psychotherapy (talk therapy), and more extreme methods such as electroconvulsive therapy (ECT). Transcranial Direct Current Stimulation (tDCS) is a novel method that proved very beneficial for treatment of depression as well as other mental disorders.
Medication Therapy
Different types of antidepressants are available for the treatment of depression. Selective serotonin reuptake inhibitors (SSRIs) increase the concentration of serotonin in the brain tissue (citalopram, fluoxetine, paroxetine, sertaline, etc.). Serotonin and norepinephrine reuptake inhibitors (SNRIs) do the same for both serotonin and norepinephrine (duloxetine, venlafaxine). Older approaches include tricyclic antidepressants (amitriptyline, doxepin, nortriptyline, protriptyline), and monoamine oxidase inhibitors (phenelzine, tranylcypromine).
Although drug therapy gives good results, it is often associated with more or less expressed side effects (indigestion, sleeping difficulties, dizziness, decreased sexual drive, anxiety, and fatigue.
Psychotherapy
Persons with depression often benefit from talk therapy provided by a psychotherapist. There are different approaches to a depressed patient, some of which include: cognitive behavioral therapy, interpersonal therapy, and problem-solving therapy. Cognitive behavioral therapy helps you realize the mechanism of depression and how it occurs. Interpersonal therapy is focused on relationships and aimed to change your behavior and bad habits towards other people. Problem-solving therapy takes particular life problems and helps you find the most appropriate solutions.
Electroconvulsive Therapy (ECT)
ECT is reserved for patients who do not show improvement from other therapy approaches. It includes provoking a short episode of seizure by passing electrical current through the brain. ECT is performed under general anesthesia and it shows immediate though temporary relief from symptoms. However, side effects such as memory loss, confusion, bone fractures, and side effects of general anesthesia may occur.
Transcranial Direct Current Stimulation (tDCS)
Transcranial Direct Current Stimulation uses electrodes located on the surface of the scalp to deliver constant electrical current of small intensity through the brain tissue (Medeiros et al., 2012). There are two types of electrical stimulation: anodal and cathodal. Unlike with ECT, these impulses are too weak to cause excitation of nerve cells, but it can act on cell membrane and induce changes in neuronal synapses (small spaces between neurons where neurotransmitters are released). Clinical studies have shown long-term synaptic changes after tDCS application (O’Neill, Sacco, & Nurmikko, 2015).
Electrodes are placed in perforated pockets with sponges soaked with saline solution. Rubber electrodes can also be used with conductive gel. Positioning of the electrodes is crucial for delivering the current in the appropriate direction, which is very important for the effectiveness of the treatment (Medeiros et al., 2012). There are recommended positions of the electrodes for each condition. For depression, the electrodes are usually placed on both sides of frontal region in order to stimulate specific parts of the left prefrontal cortex (the part of the brain which is responsible for judgment of emotions and perception of emotional status) (Ho et al., 2014). Some studies experiment with alternative positions of the electrodes.
Noticeable beneficial effects of tDCS treatment were seen in terms of improved attention and better concentration (Brunoni et al., 2014), as well as decrease in chronic neuropathic pain (Knotkova & Cruciani, 2010). This method has many advantages over ECT as it is painless, cheap, non-invasive, and generally safe. The simplicity of administration and possibility of making mobile stimulation devices makes this method preferable over other methods that involve electrical stimulation. Side effects are usually mild to moderate. Itching and tingling of the scalp are most commonly reported(Brunoni et al., 2011).
Other than for the treatment of depression, tDCS can also be used in patients with chronic pain, anxiety, and Parkinson’s disease. In the future, it can be expected for tDCS to replace standard treatment options and lower the requirements for antidepressants which are today prescribed more than ever before.
References
M. S. Reddy. (2010). Depression: The Disorder and the Burden. Indian J Psychol Med. (1): 1–2.
Yang EJ1, Baek SR, Shin J, Lim JY, Jang HJ, Kim YK, Paik NJ. (2012). Effects of transcranial direct current stimulation (tDCS) on post-stroke dysphagia. Restor Neurol Neurosci. 30(4):303-11.
Ho KA, Bai S, Martin D, Alonzo A, Dokos S, Loo CK.Clinical Pilot Study and Computational Modeling of Bitemporal Transcranial Direct Current Stimulation, and Safety of Repeated Courses of Treatment, in Major Depression. J ECT. 2015 Mar 24.
Caytak H, Shapiro D, Borisenko A, Bolic M. (2015). Outside access: advances in tDCS could provide a mainstream clinical tool for noninvasive neuromodulation. IEEE Pulse. 2015 Mar-Apr;6(2):21-4.
Brunoni, A. R., Amadera, J., Berbel, B., Volz, M. S., Rizzerio, B. G., & Fregni, F. (2011). A systematic review on reporting and assessment of adverse effects associated with transcranial direct current stimulation. Int J Neuropsychopharmacol, 14(8), 1133-1145. doi: 10.1017/S1461145710001690
Brunoni, A. R., Junior, R. F., Kemp, A. H., Lotufo, P. A., Bensenor, I. M., & Fregni, F. (2014). Differential improvement in depressive symptoms for tDCS alone and combined with pharmacotherapy: an exploratory analysis from the Sertraline vs. Electrical Current Therapy for Treating Depression Clinical Study. Int J Neuropsychopharmacol, 17(1), 53-61. doi: 10.1017/S1461145713001065
Ho, K. A., Bai, S., Martin, D., Alonzo, A., Dokos, S., Puras, P., & Loo, C. K. (2014). A pilot study of alternative transcranial direct current stimulation electrode montages for the treatment of major depression. J Affect Disord, 167, 251-258. doi: 10.1016/j.jad.2014.06.022
Knotkova, H., & Cruciani, R. A. (2010). Non-invasive transcranial direct current stimulation for the study and treatment of neuropathic pain. Methods Mol Biol, 617, 505-515. doi: 10.1007/978-1-60327-323-7_37
Medeiros, L. F., de Souza, I. C., Vidor, L. P., de Souza, A., Deitos, A., Volz, M. S., . . . Torres, I. L. (2012). Neurobiological effects of transcranial direct current stimulation: a review. Front Psychiatry, 3, 110. doi: 10.3389/fpsyt.2012.00110
Brunoni, A. R., Amadera, J., Berbel, B., Volz, M. S., Rizzerio, B. G., & Fregni, F. (2011). A systematic review on reporting and assessment of adverse effects associated with transcranial direct current stimulation. Int J Neuropsychopharmacol, 14(8), 1133-1145. doi: 10.1017/S1461145710001690
Brunoni, A. R., Junior, R. F., Kemp, A. H., Lotufo, P. A., Bensenor, I. M., & Fregni, F. (2014). Differential improvement in depressive symptoms for tDCS alone and combined with pharmacotherapy: an exploratory analysis from the Sertraline vs. Electrical Current Therapy for Treating Depression Clinical Study. Int J Neuropsychopharmacol, 17(1), 53-61. doi: 10.1017/S1461145713001065
Ho, K. A., Bai, S., Martin, D., Alonzo, A., Dokos, S., Puras, P., & Loo, C. K. (2014). A pilot study of alternative transcranial direct current stimulation electrode montages for the treatment of major depression. J Affect Disord, 167, 251-258. doi: 10.1016/j.jad.2014.06.022
Knotkova, H., & Cruciani, R. A. (2010). Non-invasive transcranial direct current stimulation for the study and treatment of neuropathic pain. Methods Mol Biol, 617, 505-515. doi: 10.1007/978-1-60327-323-7_37
Medeiros, L. F., de Souza, I. C., Vidor, L. P., de Souza, A., Deitos, A., Volz, M. S., . . . Torres, I. L. (2012). Neurobiological effects of transcranial direct current stimulation: a review. Front Psychiatry, 3, 110. doi: 10.3389/fpsyt.2012.00110
O’Neill, F., Sacco, P., & Nurmikko, T. (2015). Evaluation of a home-based transcranial direct current stimulation (tDCS) treatment device for chronic pain: study protocol for a randomised controlled trial. Trials, 16(1), 186. doi: 10.1186/s13063-015-0710-5