Multimodal Augmentation Approach with Transcranial Direct Current Stimulation in Management of Obsessive-Compulsive Disorder with Depression and Comorbid Seizure Disorder: A Case Report

To the Editor,

Obsessive-compulsive disorder (OCD) is a chronic and disabling psychiatric disorder. Despite adequate trials of treatment, a significant number of patients remain symptomatic and dysfunctional. In the management of OCD, various neuromodulation techniques such as repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS) have been used along with the conventional treatments. ¹ However, these treatments are often offered to patients with OCD who are resistant to conventional treatments.^{2, 3} We present the case of a 21-year-old male with OCD, depression, and a comorbid seizure disorder who responded well to a multimodal augmentation approach involving pharmacotherapy, psychotherapy, and tDCS.

The patient presented with complaints of recurrent intrusive thoughts about contamination and symmetry and doubts about sex, along with repetitive acts of cleaning, arranging, and checking, for 11 years. For the past six months, he has had persistent sadness and ideas of helplessness and hopelessness. Also, he has had multiple episodes of generalized tonic-clonic seizures in the past two years. He had been on antiepileptics and, at presentation, was seizure-free for the last three months. CT scan head had revealed no abnormalities.

He was diagnosed with OCD, mixed obsessional thoughts and acts, and moderate depressive episode without somatic syndrome, with seizure disorder. Earlier, he had taken various serotonergic medications (Fluoxetine up to 60mg/day, Clomipramine up to 150 mg/day, Escitalopram up to 20 mg/day) and Risperidone up to 3 mg/day in different combinations, with minimal improvement. Due to this, he would often become non-adherent to the treatment. However, for the past seven months, he has been adherent to the medications. At the time of admission, he was receiving Sertraline 300mg/day and Aripiprazole 5mg/day for OCD and Sodium valproate 1000mg/day and Clobazam 10mg/day for seizure disorder. At hospitalization, his scores on Yale-Brown Obsessive-Compulsive Scale (YBOCS) were 26 (obsession—12; compulsion—14) and Hamilton Rating Scale for Depression (HAM-D) was 15.

Owing to the nonresponse to pharmacological treatment, a multimodal treatment approach was adopted. With prior consent, as an add-on to the ongoing regimen of pharmacotherapy, he was initiated on tDCS treatment, twice daily with a gap of a minimum of three hours, for ten days. The cathode was placed over the bilateral Pre-Supplementary Motor Area, and the anode was placed over the left dorsolateral prefrontal cortex (Lt DLPFC). The current intensity used was 2 mA with a ramp time of 20 seconds. The total duration of the session was 20 minutes and 40 seconds. For the initial three days, he complained of mild headaches lasting a few hours post tDCS administration, which was treated with Tab. acetaminophen 500 mg as and when required. However, he did not report headache after the fourth day of tDCS treatment. Following each session, a tDCS side effect checklist was applied to monitor the side effects. ⁴ With tDCS treatment, over ten days, the YBOCS score decreased to 18 (obsession—9; compulsion—9), and the HAM-D score decreased to 10. After completion of tDCS treatment, the patient was given eight sessions of exposure and response prevention therapy over as many days. With this multimodal treatment, the patient reported a substantial reduction in his obsessions, compulsive behaviors, and mood symptoms. The patient was discharged after 18 days of multimodal in-patient treatment with a YBOCS score of 9 (obsession—5; compulsion—4) and HAM-D score of 8.

There are several learnings from this case. The patient had comorbid seizure disorder, yet he tolerated tDCS well without any major side effects. Thus, in line with the available literature, tDCS was safe in our patient with seizure disorder. ⁵ The protocol used in this study was unique, stimulating the Lt DLPFC and inhibiting bilateral pre-SMA. A systematic review found that most of the existing studies used anodal placement over pre-SMA. ⁶ We considered anodal placement over Lt DLPFC as it is expected to improve the depressive symptoms and cathodal placement over bilateral pre-SMA to treat the obsessive-compulsive symptoms. Hyperactivity of pre-SMA seen in OCD can be suppressed through cathodal stimulation. Augmentation of conventional treatment (anti-obsessional medications and psychological interventions) with somatic treatments like tDCS can aid in achieving an early response in OCD.^{5, 7} tDCS may be more advantageous than rTMS in patients with OCD with comorbid depression as both the conditions can be simultaneously addressed by appropriate placement of the electrodes. Besides, a multimodal treatment approach (using pharmacotherapy, tDCS, and behavioural therapy) may have an additional effect on the response, which can help achieve early response and improve functioning. However, in our case, a change in the treatment setting to a structured in-patient setting could also have played a role in the rapid response to treatment. The improvement in depressive symptoms may also impact the improvement of OCD symptoms and vice versa. It is difficult to ascertain whether this case’s improvement is primarily due to improvement in OCD or depression or both.

In patients with OCD, there is a need to see the efficacy of extended protocols of tDCS (going beyond 20 sessions) in terms of its safety and effectiveness. Similarly, the role of booster sessions (maintenance tDCS) needs to be evaluated in preventing the relapse of OCD.