Harry Guntrip in his groundbreaking book Schizoid Phenomena, Object-Relations and the Self (International Universities Press, May 2001) discussed the schizoid personality who presents in psychotherapy as withdrawn and detached. But he also discussed schizoid phenomena which can be present in a much wider range of people. The central dynamic is the oscillation between desperate hunger for a love object and the fear of being devoured, smothered or trapped. For more discussion on this topic: https://www.psychologytoday.com/blog/life-after-50/201612/the-schizoid-personality