Chapter 37: Neuroimaging in Psychiatric Disorders of Childhood

The chapter surveys major neuroimaging modalities including structural magnetic resonance imaging, computed tomography, diffusion tensor imaging for white matter assessment, functional magnetic resonance imaging for task-based brain activity, magnetic resonance spectroscopy for neurochemical measurement, positron emission tomography and single photon emission computed tomography for metabolic imaging, electroencephalography, magnetoencephalography, and functional near-infrared spectroscopy. These techniques allow clinicians and researchers to visualize brain anatomy, measure connectivity patterns, assess metabolic activity, and quantify neurochemical concentrations in pediatric populations. The chapter emphasizes that interpreting neuroimaging findings in children requires consideration of developmental stage, sex-based differences, and technical challenges such as head motion during scanning. Normal brain development progresses through synaptic elimination, axonal myelination, and region-specific cortical maturation processes that are shaped by genetic influences and environmental factors, collectively determining risk for psychiatric illness. Neuroimaging research has identified structural and functional abnormalities associated with attention deficit hyperactivity disorder, major depression, bipolar disorder, obsessive compulsive disorder, autism spectrum disorder, Tourette syndrome, post-traumatic stress disorder, childhood-onset schizophrenia, learning disorders, and eating disorders. Studies reveal that these conditions show distinct alterations in prefrontal regions, limbic structures including the amygdala and hippocampus, striatal circuits, anterior cingulate cortex, and thalamic connectivity. The chapter discusses how neuroimaging provides biomarkers that both characterize illness and predict treatment response, such as normalized fronto-striatal activation following stimulant treatment in attention deficit hyperactivity disorder or reduced glutamate concentrations in striatal regions after selective serotonin reuptake inhibitor administration in obsessive compulsive disorder. Integration of neuroimaging with the Research Domain Criteria framework allows psychiatry to conceptualize disorders as identifiable dysfunctions of brain circuits measurable through neuroscience methods. By combining neuroimaging data with genetic information and clinical assessment, the field can advance toward personalized medicine approaches tailored to individual developmental trajectories and biological profiles, ultimately improving early identification and intervention outcomes.