title: Impact of antipsychotic medication on transcranial direct current stimulation (tDCS) effects in schizophrenia patients.
abstract: Transcranial direct current stimulation (tDCS) has generated interest as a treatment modality for schizophrenia. Dopamine, a critical pathogenetic link in schizophrenia, is also known to influence tDCS effects. We evaluated the influence of antipsychotic drug type (as defined by dopamine D2 receptor affinity) on the impact of tDCS in schizophrenia. DSM-IV-TR-diagnosed schizophrenia patients [N=36] with persistent auditory hallucinations despite adequate antipsychotic treatment were administered add-on tDCS. Patients were divided into three groups based on the antipsychotic's affinity to D2 receptors. An auditory hallucinations score (AHS) was measured using the auditory hallucinations subscale of the Psychotic Symptom Rating Scales (PSYRATS). Add-on tDCS resulted in a significant reduction inAHS. Antipsychotic drug type had a significant effect on AHS reduction. Patients treated with high affinity antipsychotics showed significantly lesser improvement compared to patients on low affinity antipsychotics or a mixture of the two. Furthermore, a significant sex-by-group interaction occurred; type of medication had an impact on tDCS effects only in women. Improvement differences could be due to the larger availability of the dopamine receptor system in patients taking antipsychotics with low D2 affinity. Sex-specific differences suggest potential estrogen-mediated effects. This study reports a first-time observation on the clinical utility of antipsychotic drug type in predicting tDCS effects in schizophrenia.
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Sri Mahavir
authors.initials: SM
authors.lastname: Agarwal
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Anushree
authors.initials: A
authors.lastname: Bose
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India; Department of Clinical Neurosciences, NIMHANS, Bangalore, India.
authors.forename: Venkataram
authors.initials: V
authors.lastname: Shivakumar
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Janardhanan C
authors.initials: JC
authors.lastname: Narayanaswamy
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Harleen
authors.initials: H
authors.lastname: Chhabra
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Sunil V
authors.initials: SV
authors.lastname: Kalmady
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Shivarama
authors.initials: S
authors.lastname: Varambally
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Göttingen, Germany; Leibniz Research Centre for Working Environment and Human Resources, Dortmund, Germany; Department of Neurology, University Medical Hospital Bergmannsheil, Bochum, Germany.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Nitsche
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India. Electronic address: venkat.nimhans@yahoo.com.
authors.forename: Ganesan
authors.initials: G
authors.lastname: Venkatasubramanian
authors.affiliation: The Schizophrenia Clinic, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India; Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: Bangalore N
authors.initials: BN
authors.lastname: Gangadhar
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology*; D003131:Combined Modality Therapy; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006212:Hallucinations / Q000523:psychology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D012559:Schizophrenia / Q000150:complications / Q000628:therapy*; D012737:Sex Factors; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D017448:Receptors, Dopamine D2
keywords: Antipsychotic; Dopamine; Estrogen; Schizophrenia; tDCS