Breastfeeding and Complementary Feeding Practices of Children with Stunting in Guatemala.

Cognitive impairment is a core and enduring feature of schizophrenia, affecting multiple domains and representing one of the strongest determinants of functional outcome, disability, and quality of life (; ). Deficits in working memory, processing speed, attention, learning, and executive functioning are often present early in the course of illness, remain relatively stable over time, and show limited responsiveness to antipsychotic treatment (; ). As a result, cognitive dysfunction remains a major unmet therapeutic need in schizophrenia, despite substantial advances in the pharmacological management of psychotic symptoms (; ). Non-pharmacological interventions aimed at modulating neural plasticity and prefrontal network function have therefore attracted increasing interest (). Among these approaches, transcranial direct current stimulation (tDCS) is a promising neuromodulatory technique because it can modulate cortical excitability, influence synaptic plasticity, and engage prefrontal circuits involved in cognitive control (; ; ). In addition, compared with more resource-intensive neuromodulatory approaches, tDCS is relatively inexpensive, portable, well tolerated, and suitable for repeated multi-session protocols, making it a potentially scalable intervention for cognitive impairment in schizophrenia (). Clinical studies of tDCS in schizophrenia have reported improvements in several cognitive outcomes, including cognitive insight, higher-order neurocognitive performance, and working memory, although findings have not been uniform across trials (; ; ; ; ; ; ; ). Meta-analytic evidence also suggests that multi-session prefrontal tDCS may exert modest pro-cognitive effects in schizophrenia, but with substantial between-study heterogeneity (; ). This variability may reflect differences in stimulation parameters, montage, treatment duration, outcome measures, concomitant interventions, and sample characteristics. Importantly, it may also reflect clinically meaningful heterogeneity in baseline cognitive status, which is rarely incorporated into trial design or analysis.