At birth, all infants underwent standard clinical exams under blinded conditions. On each of the first four days of life and then at two weeks and two months, each infant underwent a neurologic status exam by pediatricians "trained to perform examinations using a specific scale for symptoms seen in a state of serotonergic overstimulation." The exam included vital signs and observation for serotonergic symptoms including myoclonus, restlessness, tremor, shivering, hyper-reflexia, incoordination (assessed by general movements), and rigidity. In addition, each infant in the SSRI group underwent brain ultrasound and magnetic resonance imaging perinatally (at about 38 weeks) and at two months old. In each infant in the SSRI group, blood work was done to monitor levels of the active medications and their metabolites and prolactin levels. Identical laboratory studies were performed on the infants in the control group.