Many people describe a premonitory urge that precedes a tic. This premonitory urge is a feeling similar to what you feel when you need to sneeze or when you have an insect bite that itches. With tics, the premonitory urge is described as a build up of pressure, tension or energy that is relieved when the tic is expressed. The temporary ability to withhold or suppress a tic is somewhat like the feeling of holding in a sneeze or trying not to scratch an insect bite. The ability to suppress tics varies between individuals. Tic suppression can take a lot of energy, making it hard to concentrate on other tasks. The effort required to suppress tics can also be exhausting. Most people who try to suppress their tics report that the tic will eventually be released. Young children may not be aware of their tics, and even if they are aware they may have no ability to suppress their tics. Asking a child to suppress their tics is generally not a good idea because the effort involved in suppressing the tics involves a high level of concentration and it makes it difficult for the child to pay attention to other tasks such as paying attention in class. In fact many children and teens with TS find that when they are in a supportive environment where they can tic without attention being paid to the tics, there is a decrease in the number of tics they experience. It used to be thought that suppressing tics caused a rebound effect after the suppression is stopped. This was described as the expression of all the tics that had been suppressed when the person could no longer suppress them. However, more recent studies have disproven this rebound effect. The study resulted showed that the number of tics did not substantially increase following a period of suppression. Many parents observe that their child or teen will try to suppress their tics at school and then will come home and explode in bouts of tics. This is often accompanied by other emotional behaviours. The studies on the rebound effect of suppressing tics indicates this behaviour is not the result of suppressing tics, and that further study is required to fully understand the behaviour.