Marijuana, aging, and task difficulty effects on pilot performance.

This study provides evidence that diverse factors can cumulatively contribute to human/machine performance decrements. In separate sessions, young and old pilots smoked one of three cigarettes containing either 0 mg, 10 mg, or 20 mg of the active ingredient, delta 9 THC. They flew a calm and a turbulent flight in a light aircraft simulator at 1, 4, 8, 24, and 48 hour (h) delay after smoking. Effects were found at 1 and 4 h after smoking in the turbulent flight conditions when 20 mg cigarettes were smoked. Drug dose level, age, weather conditions (i.e., task difficulty), and delay period all affected pilot performance. Most important, these variables produced cumulative performance decrements.