Neuropsychiatric disorders are a leading cause of global disability-adjusted life years, and solutions are lacking. Can digital twins be useful? Recent findings suggest that non-invasive brain stimulation may be a valuable option in conditions such as epilepsy or Alzheimer's (AD). Personalised hybrid brain models uniting the physics of electromagnetism with physiology – neurotwins or NeTs – are poised to play a fundamental role in understanding and optimizing the effects of stimulation at the individual level. With research at the intersecting frontier of nonlinear dynamics, network theory, biophysics, engineering, neuroscience, clinical research, and ethics, Neurotwin will deliver model-driven breakthroughs in basic and clinical neuroscience, with patients ultimately benefiting from safe, individualized therapy solutions.