Among the depth-psychology tools we need for living life (most of them covered in The Undervalued Self), understanding complexes is your handy screwdriver. It opens up many things and closes some as well. We all have complexes. They are the "building blocks of the personality," as Jung called them. Alas, they are also our loose screws, because most of them are built around old traumas.
Psychological trauma happens in moments of unbearable feelings that threaten to make your ego (self) literally fall apart or dissociate and be sent out of awareness. A complex (or emotional schema, the more recent technical term used in The Undervalued Self) contains all the conscious and unconscious thoughts, feelings, memories, sensations, and, above all, self-protections, both learned and innate, that are associated with a trauma. Anything new that seems associated with the complex—a comment, person, place, scent—brings up the entire bundle. Suddenly you are behaving as if you are back there again, not here and now.
Freud told us about the oedipal complex, developed sometimes around a boy's fear of making Dad jealous, but that was only the tip of the iceberg. You can have a complex about almost anything—a trust complex due to a past betrayal, or a complex due to traumas surrounding your gender, race, or sexual preference, or a complex about money, success at all cost, separation and loss, abandonment, God, and of course Mother. She was our first relationship, when we were helpless. We all have a mother complex of some sort.
A complex helps you avoid horrible emotional pain by making danger signs out of anything like the first trauma. It is very conservative, preferring to avoid retraumatization over risking a new perspective. Plus, because the stuff stored in a complex is so painful, much of it stays unconscious and unquestioned as it adds new triggers out of the most trivial events or self-fulfilling reenactments. (Jill gets crazy with jealousy, so Jack gets tired of it and really does leave her for someone new.) It can become like a black hole, assimilating more and more of your life.
One of life's essential tasks if you want to be a conscious person is to bring your complexes into your awareness. You can't always prevent them being triggered, but you can learn to spend less time in them.
Another reason to understand complexes is to comprehend what's going on when someone else is in one. You already sort of know. People in a complex become more emotional about something than it seems to warrant. Their voice becomes strident or intense. You hear dire threats and predictions. "Always" and "never" pepper the conversation. You sense a crazy level of defensiveness. If you can be implicated, one side of the complex will be projected onto you, because complexes always have two poles, becoming two roles (e.g., victim and dominator, ignorant and wise, sick and healthy). You may be blamed, labeled, warned, or diagnosed in a bewildering fashion. With very rational types, a discussion becomes a debate, and then a monologue designed to prove you wrong. Above all, you feel sucked into a drama, treated like a character in the play and not you. You have become invisible. Maybe you thought this person cared for you, but it doesn't feel like it now.
If you are the one in the complex, you may be watching yourself doing all of this and be amazed.
What to do? I'll write about you and your own complexes another time. With someone else in a complex, first, never argue—this person is in some kind of completely unconscious panic. Don't agree either, and if silence gets you in trouble, try saying something nice but off the topic. "That reminds me of how much I enjoyed your presentation yesterday." If nothing else works and this is not an ongoing relationship, excuse yourself and exit stage right.
If the person matters to you at all, things can get messy. Again, try not to argue or become hurt and defensive yourself. Alas, you will need to talk about the event when the person is no longer in the complex. "I wonder what was happening last night at dinner. You seemed very upset." Of course you are treading on thin ice just bringing it up again, but you must. I will write another time on how to deal with complexes in ongoing relationships and in yourself. (You can read more about both in The Undervalued Self.) But for now you have a screwdriver for getting out of somebody else's psychological box. Again, here's what it does.