This depends on the child's personality, the nature of the bond between the child and the therapist and the nature of the problem. Some children are very shy and need a lot of encouragement to express their feelings and thoughts, while others are quick to talk. Children who have been hurt badly by adults might be apprehensive and might need a long time to trust someone and feel free to talk. Some children have developed clever ways to avoid thinking about their feelings because this is too painful for them and they need time to feel safe to break down their barriers and build courage to deal with their emotions and the painful events in their lives.
In general, a child or adolescent attends therapy for at least 10 therapy sessions as this usually gives sufficient time to build a relationship of trust and to have time to discover more about feelings and thoughts, to feel free to express them and to start talking about solutions