If it is safe to eat the oil used for OP or rub that oil on your skin (our largest organ), then it is absolutely safe. At the same time that person with bipolar is OP'ing, she is also absorbing a good amount of the EFA's from the oil, i.e., if the oil is excellent quality organic, cold-pressed, extra virgin stored in glass bottles.
Check out some of these links that relate specifically to EFA's benefiting bipolar and other brain challenges.
Highlights of a Lecture by Andrew L. Stoll, M.D., whose study found Omega-3s had many of the same characteristics as effective mood stabilizers. http://mddaboston.org/HTML/lect060999.html