Buy Ambien Online dependence can develop in just two weeks, regardless of whether a user is abusing or following a prescription. Ambien dependency is characterized as tolerance where the user needs to take larger doses of the substance in order to get the same effects, and withdrawal symptoms that appear when the user reduces or stops taking their dosage. Ambien addiction can develop over time. It is characterized as a full-blown dependence, which includes tolerance, withdrawal symptoms and impaired control. Most people are unaware of their problem until they quit taking Ambien and find they can't sleep without it.