Transcranial Direct Current Stimulation to Enhance Cognition and Functioning in Schizophrenia

Schizophrenia is a heterogeneous disorder with characteristic symptoms, including cognitive impairments that are associated with the illness and its outcome. Cognitive impairments include deficits in processing speed and working memory, inattention, and impaired problem-solving ability. These cognitive insufficiencies are considered to reflect the core of the disorder and to worsen as the disorder progresses, further impairing functioning. Novel approaches to treat cognitive impairments are greatly needed and transcranial Direct Current Stimulation (tDCS) is a promising modality that may address these cognitive impairments. TDCS is a noninvasive, non-pharmacological neuromodulation technique that has demonstrated efficacy in improving attention processing in normal controls and in persons with diverse pathologies. By modulating cortical excitability, anodal (excitatory) tDCS to the Prefrontal Cortex (PFC) may facilitate access to existing PFC neural reserves in people with schizophrenia, potentially improving attention. However, this possibility has been only minimally investigated to date. Because cognitive deficits are the strongest determinant of poor functional outcomes in schizophrenia, the development of novel treatments and the combination of innovative neuromodulation and medication strategies to improve cognition and functional capacity are needed. In addition to reviewing cognitive impairments in schizophrenia, this article discusses the potential of tDCS targeting the PFC in patients. It also describes the use of measurement tools as proposed by the National Institute of Mental Health (NIMH) initiative “Measurement and Treatment Research to Improve Cognition in Schizophrenia” (MATRICS), to improve attention processing and to isolate distinct cognitive disruptions in patients with schizophrenia. Recommendations are made for future research approaches.