There is a major variable that must be considered when answering this question: Age. If the client is under the age of 18, what transpires between client and therapist can be discussed between parent and therapist. However, since such discussions with the parents undermine trust with the client, most therapists become reluctant to include the parents in this way as the child gets older. Typically, most child therapists will minimize the degree to which child/therapist dialog is discussed with parents unless the circumstances clearly warrant it. On the other hand, it is the duty of the therapist to periodically provide an update or progress report to the concerned parent(s). Teenagers, in particular, need to be aware that therapists are probably going to let the parents know when the teen client is abusing drugs, particularly if that is the reason for treatment in the first place. However, this is said with one caveat: For those clients who are underage, the law provides for them the opportunity to invoke privilege of their communication for issues they proclaim they want held in confidence.
For example, if a female teenager says that she is pregnant and does not want her parents to know, the therapist is not allowed to divulge that information. The therapist may believe that such an issue should be told to the parent(s), and may discuss it with the pregnant teen in order to try to convince her it is in her best interest to tell her parents, but he/she cannot tell the parents of the client's situation.
Certain issues and discussions will not be held in confidence, regardless of age. If, for example, a client is believed to be homicidal, then the therapist is bound by law to notify the person being threatened as well as the police. Also, should a client of any age mention that he or she is going to blow up a building or hurt someone physically or kill someone, then the therapist or counselor has the duty to report such threats.