Efficacy and neural mechanisms of transcranial direct current stimulation for social function in children and adolescents with autism spectrum disorder: A systematic review and meta-analysis.

In 30 seconds

This systematic review and meta-analysis assessed transcranial direct current stimulation (tDCS) for social functioning and neurophysiological outcomes in children and adolescents with autism spectrum disorder. It included 13 randomized controlled trials involving 357 participants aged 4–21 years. tDCS was associated with improved social functioning (SMD = -0.51, I 2 = 0%, p = 0.0002) and significant overall neurofunctional modulation (SMD = 1.03, I 2 = 71.9%, p = 0.004). However, neurobiological and behavioral effect sizes were not significantly correlated across studies, and consistency varied between individual studies.

Key findings

• Social functioning improved with tDCS (SMD = -0.51, I 2 = 0%, p = 0.0002).
• Overall neurofunctional modulation was significant, with substantial heterogeneity (SMD = 1.03, I 2 = 71.9%, p = 0.004).
• Neurobiological and behavioral effect sizes were not significantly correlated across studies (r = 0.19, p = 0.760).
• Of five studies assessed for individual-level consistency, two were fully consistent, two partially consistent, and one inconsistent.

Why it matters

The findings suggest that tDCS may affect social functioning in young people with autism, while measured neural responses do not yet provide a clear cross-study explanation for behavioral effects. The differing results across neurophysiological modalities and variable study-level consistency underscore the need for standardized outcome measures before neural changes can be interpreted reliably or used to guide intervention research.

What to keep in mind

The evidence comes from 13 trials with 357 participants, and neurofunctional results were heterogeneous. Individual-level consistency was assessed in only five studies; ERP findings were based on limited data (k = 2).