When it comes to a person's diary or their personal private journal, the truth is that these are rarely going to be considered confidential in a court of law. A person seeking emotional distress damages in a lawsuit, or embroiled in a nasty custody dispute or divorce, may be required to turn over their personal diary.
Diaries are, however, private as opposed to confidential. Barring extraordinary circumstances, diaries cannot be published or broadcast without permission.
Personal Diaries in the Courtroom
When a person is involved in any civil lawsuit, their personal diary could arguably contain relevant evidence. Legally, under the rules of evidence and discovery, a party is entitled to inspect and copy any and all documents that could potentially lead to the discovery of useful evidence to support their case or position. While a diary is going to be considered hearsay, there are numerous exceptions to hearsay rules that would allow a diary's use in court.
Even if a diary doesn't contain relevant evidence, courts will usually allow the side requesting to see it to make that determination for themselves. Particularly in cases where a party is alleging physical or emotional injuries, diaries are rather helpful in understanding what a person has experienced due to their injury. If a party kept a diary before the injury occurred, it can also help to show the contrast between life prior to and after the injury.
Often times, attorneys will ask their clients to keep diaries regarding the damages they suffer. For example, in a broken bone injury case, an attorney may ask their client to write down how much pain medication a person takes on a daily basis, or whether the pain was severe or mild on each day. Also, these can include activities a person could not participate in due to their injury. Other types of cases may require including other types of information.
Although these diaries can be rather helpful in court, these will usually be considered confidential as attorney-client communications. This means that a party will not be required to disclose this type of diary if it was specifically requested by and prepared for their attorney. However, if the attorney believes it will be helpful in the case, then it may be disclosed by choice.
Personal Diaries Generally
Your dearest diary, the one with the locking clasp and key that you wear around your neck, may not be confidential enough to avoid disclosure in court, but when it comes to publication of your private facts and thoughts, you have legal privacy protections. Generally, if embarrassing private facts are disclosed publicly, you may be able to take legal action against the person who disclosed your private writings, facts or thoughts.