NO. Methadone has no adverse effects on intelligence, mental capability, or employability. Methadone treated patients are comparable to non-patients in reaction time, in ability to learn, focus, and make complex judgments. Methadone treated patients do well in a wide array of vocational endeavors, including professional positions, service occupations, and skilled, technical and support jobs. One recent study tested methadone patient's cognition, perceptual and motor functioning, reaction time, and attentional function, as well as performance of automobile driving behavior. It was concluded, confirming pervious findings, that methadone does not impair functional capacity.