Signs that someone is developing a problem with alcohol and/or drugs cover a wide range and many of them are apparent on the job. Unfortunately, no one wants to believe that a friend, coworker or family member has a substance abuse problem. Subtle changes in behavior often are discounted. Changes in friends, lack of interest in old hobbies and increasing isolation are all minimized. Nonetheless, there is usually ample evidence of a problem if you are willing to recognize the connection between the behavior you observe and the drug and alcohol use.