Although the relation between child maltreatment and psychiatric impairment is well documented and preliminary evidence has linked child maltreatment with aberrant cortical connectivity of the left hemisphere, no investigations have attempted to examine these relations in the same study. Here, we examined the links among early adversity, brain connectivity, and functional outcomes. We collected resting regional EEG intra- and interhemispheric α-band (7.5–12.5 Hz) coherence and measures of general psychiatric impairment from a cohort of 38 adolescent females exposed to child maltreatment (
Mage = 14.47) and 24 adolescent females not exposed to child maltreatment ( Mage = 14.00). Maltreated youths exhibited more left hemisphere EEG coherence than the control youths, suggesting a suboptimal organization of cortical networks. Maltreated participants also showed reduced frontal (anterior) interhemispheric coherence. These differences in brain circuitry remained statistically significant even after controlling for group differences in pubertal status and socioeconomic status. Measures of functional brain connectivity were associated with several subtypes of abuse and neglect. It was important that atypical left hemisphere EEG coherence mediatedthe effects of child maltreatment on levels of psychiatric impairment. The findings are discussed in the context of models linking early adversity to brain function and psychopathology.