Use of Transcranial Direct Stimulation in the Treatment of Negative Symptoms of Schizophrenia

Abstract

Schizophrenia is a debilitating disease that affects approximately 1% of the population. Negative symptoms are among the major determinants of the functional impairment and a significant proportion of patients with negative symptoms will continue to experience these symptoms despite antipsychotic medications. There are promising results in the application of brain stimulation, particularly transcranial direct current stimulation (tDCS), for the reduction of negative symptoms of schizophrenia. However, findings are still controversial. This is a selective review of the literature published between 2011 and 2017 on use of tDCS in treatment of negative symptoms of schizophrenia. We included only randomized controlled trials where schizophrenia and negative symptoms were assessed using any psychometrically validated scale (eg, Positive and Negative Symptoms Scale or Scale for the Assessment of Negative Symptoms). Studies of participants with neurological conditions were excluded, as were those that did not report any symptom outcome variables. Only 5 studies are included. Three studies showed a decrease of negative symptoms. The other studies did not show any therapeutic effects of tDCS in the severity of positive and negative symptoms compared to controls. Our findings suggest that negative symptoms in schizophrenia can be treated with tDCS over the dorsolateral prefrontal cortex, but results are affected by several factors, such as the electrode montage, the concomitant medication, the homogeneity of the sample, the intensity of the tDCS treatment. Further randomized, double-blinded, sham-controlled studies in large samples are still needed to establish the effectiveness of the tDCS in the treatment of negative symptoms in schizophrenia, but there is the potential for tDCS to become a useful complementary treatment option in this population.

The Current and Future Potential of Transcranial Magnetic Stimulation With Electroencephalography in Psychiatry

“…Although antipsychotic medications have proven to be effective for ameliorating positive symptoms by targeting imbalances in the dopaminergic and glutamatergic systems, treatment has not been promising for negative and cognitive symptoms, which remain the strongest predictors of functional disability . Disruptions in prefontal activity, including abnormal cortical inhibition, have been proposed to mediate these symptoms . Notably, cortical inhibition can be directly targeted with TMS‐EEG and holds potential to serve as a therapeutic target in SCZ for the treatment of cognitive and negative symptoms .…”

Advances in clinical staging, early intervention, and the prevention of psychosis

“…Transcranial direct current stimulation (tDCS) may be a promising intervention tool when symptomatology and cognitive function begin to be impaired [113][114][115][116][117] . This technique has been found to reduce symptomatology 118,119 and improve neurocognitive functions 120 and social cognition 117 . While work in this area is still under way in order to answer remaining questions such as side effects, appropriate length of stimulation, and overall efficacy, this technique has potential to serve as a prevention and intervention strategy, particularly when symptoms begin to emerge.…”

Transcranial Direct Current Stimulation, Symptomatology, and Cognition in Psychosis: A Qualitative Review

“…There is also research exploring the impacts of tDCS on negative symptoms ( Osoegawa et al, 2018 ; Pontillo et al, 2018 ). Previous work has examined negative symptoms in conjunction with positive symptoms such as auditory hallucinations, also targeting the DLPFC ( Brunelin et al, 2012 ; Fröhlich et al, 2016 ).…”

“…To date, there are informative reviews investigating the impacts of tDCS on schizophrenia populations (e.g., Brunoni et al, 2014 ; Fregni et al, 2015 ; Fröhlich et al, 2015 ; Kadosh, 2015 ; Mondino et al, 2015 ) and more recent reviews discussing tDCS and symptoms ( Osoegawa et al, 2018 ; Pontillo et al, 2018 ). However, there have been several new tDCS studies conducted which are summarized in the current review.…”