There is a great wisdom statement from the ancient worlds that says we become what we meditate on. Another way of saying this is that we take on the properties of what we put our attention on. For example, if we put our attention on sad music we tend to become sad. Another example would be watching too much of the news and becoming fearful (as the news of the day tends to cover many dire stories).
The psychological process of identification is similar to this ancient wisdom saying. Psychological identification occurs when a person assimilates an aspect or property of something outside of themselves and is changed by it. Consequently, what we identify with becomes part of our psychological landscape, part of who we are. And in fact, our psychological identifications create our reality and our expectations. The greater we identify with something, the greater it contributes to our reality. This is beneficial if the identification is healthy and supports growth and equanimity. Unfortunately, many times our identifications are not helpful and even toxic. And we are not always very aware of what we have identified with, which can compound our difficulties. This can be a formula for great amounts of unnecessary suffering. This is the case with identification with illness, where we have made being sick a significant part of our identity. Read the module on this topic that follows and then score yourself on the identification with illness scale: