Background: Some patients with schizophrenia suffer from continuous auditory hallucinations that are refractory to antipsychotic medications.
Methods: Transcranial direct current stimulation (tDCS) was used to treat a 24-year-old female schizophrenia patient who had severe, clozapine-refractory, continuous, psychosocially and cognitively disabling auditory hallucinations. The tDCS cathode was placed midway between T3 and P3, and the anode over F3, in the 10-20 electroencephalogram electrode positioning system.
Results: Once daily, 20-minute tDCS sessions at 1-mA intensity produced noticeable improvement within a week: cognitive and psychosocial functioning improved, followed by attenuation in the experience of hallucinations. There was greater than 90% self-reported improvement within 2 months. Benefits accelerated when the current was raised to 3 mA; treatment duration was increased to 30-minute sessions, and session frequency was increased to twice daily. The patient improved from a psychosocially vegetative state to near-normal functioning. Once- to twice-daily domiciliary tDCS was continued across nearly 3 years and is still ongoing. Benefits attenuated or were even lost when alternate day session spacing was attempted, or when electrode positioning was changed; benefits were regained when the original stimulation protocol was reintroduced. There was confirmation of benefit in 2 separate on-off-on situations, which occurred inadvertently and under blinded conditions. There were no adverse events attributable to tDCS.
Conclusions: This is the first report in literature of the safe and effective use of daily to twice-daily, domiciliary, 30-min, 1- to 3-mA tDCS sessions across nearly 3 years for the treatment of continuous, disabling, clozapine-refractory auditory hallucinations in schizophrenia. Key learning points emerging from this case are presented and discussed.