Some patients with schizophrenia suffer from continuous auditory hallucinations that are refractory to antipsychotic medications.
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.
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.
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.