James Holmes -- Reportedly Took Drugs Before Shooting Spree

James Holmes took Vicodin 2-and-a-half hours before yesterday's shooting rampage ... this according to a new report.

According to KMGH TV in Denver, Holmes took 100 mg of Vicodin late Thursday night.

Meanwhile a man who lived across the street from Holmes told the NY Post he used to "see him smoking weed behind the apartment." He told the paper, "Nobody ever really talked to him. He was alone a lot."