Children who sustain head injuries react much differently than adults who develop a fairly typical post-concussion syndrome of headaches, dizziness, and irritability. In 47 of the 50 children studied, personality changes and psychological phenomena were the outstanding post-concussion symptoms. Behavioral changes, including increased aggressiveness, regression and withdrawal, and antisocial behaviour were shown in 31. Sleep disturbances were extremely common, and 8 children developed enuresis. Post-concussion electroencephalographic abnormalities, frequently seen, usually disappeared. Clinical seizures were developed by 8 children. Reassurance and mild tranquilizers often sufficed for treatment. Intensive psychotherapy was sometimes necessary. Anticonvulsive medication was used when clinicalseizures occurred or electroencephalographic changes were found.