The following work by Sebastian Bieniek is intriguing in regards to it's link with the bipolar disorder. Based on the idea of giving people two faces using their one, there is a connection with how bipolar disorder can often seem as though a single person is acting completely differently from one day to the next.
When I look at it, I see a message of how one person can be many people. We don't all act the same way all of the time to every person. It is not uncommon to shift our behaviours to suit specific situations, or depending on who we are with. I think it would be within reason to suggest that my client may well use such methods and layers of meaning within their own work.