Lower functioning clients, the ones who have the most trouble with everyday life, sometimes present in therapy with a mixed and very confusing set of symptoms. It can be hard to categorize them because they have so many problems. Sometimes they may seem almost psychotic; other times they seem to be presenting with features of all the personality adaptations.
Ralph Klein uses an interesting analogy to describe the difficulties of diagnosing this lowest function group. He suggests that we picture the Borderline, Narcissistic, and Schizoid adaptations of the self as three separate high-rise buildings that share a common basement. There is the Borderline building, the Narcissist building, and the Schizoid building. The higher floors contain clients who have made a clear adaptation that fits rather neatly into that particular category of building. The lowest functioning clients, who present such a mixed, chaotic picture in therapy that it is hard to definitively diagnose them as having one disorder or the other, are in the "Basement Category." Depending on their mood and life circumstances, these clients can run back and forth below all three buildings and show symptoms and behaviors in session that fit into more than one diagnosis.