Modulation of self-appraisal of illness, medication adherence, life quality and autonomic functioning by transcranial direct current stimulation in schizophrenia patients

Objectives: Little is known about the impact of fronto-temporal transcranial direct current stimulation (tDCS) on attitudes toward mental illness, psychosocial and autonomic functioning, life quality, and medication adherence among schizophrenia patients.

Methods: Sixty schizophrenia patients were randomly allocated to receive 10 sessions of active (2 mA, 20 min, 2 sessions/day for five weekdays) or sham fronto-temporal tDCS. Self-Appraisal of Illness Questionnaire (SAIQ), Medication Adherence Rating Scale (MARS), World Health Organization Quality of Life-BREF (WHOQOL-BREF) and indices of heart rate variability (HRV) were measured at baseline, immediately after tDCS and at one-month follow-up visit.

Results: There were significant group-by-time interactions for scores of SAIQ presence/outcome subscale, total MARS and its subscale of subjective response to taking medication, WHOQOL-BREF psychological domain. Relative to sham, tDCS significantly improved self-awareness of presence/outcome of schizophrenia (Cohen's d = 0.465, p = 0.0011), subjective response to taking medication (Cohen's d = 0.639, p < 0.001) and psychological domain of life quality (Cohen's d = 0.459, p = 0.00114). These effects lasted for less than one month. The group-by-time interactions were non-significant for clinician-rated psychosocial functioning, mean RR intervals, and all HRV indices.

Conclusion: Fronto-temporal tDCS briefly optimizes self-reported insight levels, beliefs about treatment adherence, and psychological domain of life quality in patients with schizophrenia. Further studies are required to confirm whether patients treated with 5-day, 10-session tDCS in combination with multisession "maintenance" stimulation every month would attain favourable outcomes.

Significance: We provide novel evidence for the potential utility of tDCS in schizophrenia.