What is the cause of the bipolar disorder that has resulted in the hospitalization of my client?

This, indeed, is the consequence of spirit meddler infestation. This happened during a weak moment and essentially has knocked him for a loop, so to speak, as fits the description of the sudden transformation while away at college to make him end up in a state of mind where he was out of control and uncooperative. As such, the diagnosis from a descriptive standpoint is fitting, but of course never carries with it a true understanding of the inner causes, mechanisms, and the best avenue to obtain healing. So your work on him with the Lightworker Healing Protocol will begin to right the ship. He will need time to recover from the distortions introduced within his mind. It is a general truism that when people develop extreme abnormal thoughts and delusional thinking it is because their own mind, itself, has become corrupted in the way it thinks and conclusions it derives, as a consequence of that distortion within the beliefs that has been produced by a spirit presence. As such, it becomes the way the person is, in terms of their inner programming, so to speak. That is why people cannot switch from abnormal to normal simply by removing the instigator. It is very analogous to a dog living with someone who abuses it to make it mean and to hate people, such as for duty as protector of property where no one would be safe to enter while the dog is on patrol. Simply removing that individual will not change the dog. Once the trainer has done their work, the effects will persist and this is true for people who have been manipulated by the darkness many times, in having ingrained beliefs and ways of thinking that will keep recurring, for a time at least. Eventually, we will be able to heal and remove these traces, but it will take time. The key is to remove the bad influence that set this in motion so nothing new is contributed and no additional reinforcement will be taking place and that is a requisite for healing to be effective. That healing will now be underway.