My son, age 23, is diaphoretic, has trouble sleeping, has been abusing drugs since age 13. Doc heroin. Has been in and out of rehab the past 4 years. Supposedly clean. He's displaying all the previous signs of using but refuses to take a home urine test. He just started training to be a welder and got a job at the same time. My gut says he's using but he insists he is not. Could this be a stress reaction to life changes, or anxiety?