RESUMEN
OBJECTIVE: This study was designed to explore the efficacy and feasibility of cognitive behavioral therapy (CBT) along with pregabalin and compare it with pregabalin monotherapy for the management of neuropathic pain in post-herpetic neuralgia (PHN) patients and to explore the modulation of messenger RNA (mRNA) expression of interleukin (IL)-6 and mammalian target of rapamycin-1 (mTORC1) genes in these patients. DESIGN: Randomized controlled pilot study. METHODS: The patients aged >18 years of age with an established diagnosis of PHN with evident allodynia and hyperalgesia who had pain for at least 3 months after healing of rash with pain intensity ≥4/10 on NRS-Pain Scale were enrolled. The trial was registered with the Clinical Trials Registry-India (CTRI/2019/03/018014). A detailed baseline assessment regarding type and duration of pain and disability using pain-relevant self-report questionnaires was done. Two mL venous blood samples were collected for gene expression studies at base line and at end of 12 weeks of treatment. Patients were randomized into one of the two groups. Group PR received pregabalin and Group CP received CBT along with pregabalin. The pain intensity was measured using numeric rating scale (NRS)-Pain scale, neuropathic component of the pain by using Neuropathic Pain Symptom Inventory (NPSI) and Pain Detect Questionnaire (PDQ), sleep interference by NRS-Sleep, pain-related catastrophic thoughts by using Pain Catastrophizing Scale (PCS), depression and quality of life using Beck Depression Inventory-II (BDI-II) and Short Form-12 (SF-12), respectively. The research funding was supported by the intramural grant from the institution. RESULTS: A total of 40 patients with 20 in each group were included. Following integrated approach encompassing CBT and Pregabalin, group CP had significant downregulation of mRNA expression of IL-6; however, no such correlation was observed with mTOR expression. A significant decline in the intensity of pain, NPSI scoring for burning, allodynia, and pain-related catastrophizing were observed; also a significant improvement in depressive symptoms and quality of life were observed with the use of CBT. CONCLUSIONS: A significant downregulation of mRNA expression of IL-6 was observed; however, no significant correlation was observed between NRS pain score and ΔCt values of mRNA expression of both mTORC1 gene and IL-6 gene at baseline and at the end of 12th week. In addition, we note a significant decrease in pain intensity, depressive symptoms, and pain-related catastrophizing while improving QOL was observed with the use of CBT as a clinical adjunct along with pregabalin in PHN patients.