Here are three insights from modern psychoanalytic theory and my comments to apply those to performance fields such as trading:
1) We internalize our sense of self from our significant relationship experiences. Relationships serve as a kind of psychological mirror, by which we can experience ourselves through others. If our relationships are positive and healthy, we're more apt to internalize a positive sense of self. It's only a small step from this insight to the realization that we have a relationship with *all* of our life activities. We experience ourselves through our trading: over time trading without an edge and without proper risk control virtually ensures that our trading will take a personal toll.
2) We defend ourselves against sources of anxiety. These defense mechanisms may keep us from becoming anxious, but they often are maladaptive and create problems in social and work situations. If we're feeling inadequate or vulnerable, we might defend against these feelings by jumping into trades or by avoiding markets altogether. What we do to manage our feelings often is the opposite of what we need to do to properly manage our money and positions.
3) We tend to replay conflicts in past relationships in our current relationships. These unresolved problems reappear in different situations until we find resolution. Many trading problems occur when we act out our needs for recognition and self-worth in our trades. The trader who breaks rules when trading and takes undue risk often is needing the markets to provide desired emotional experiences, not just profits. To the degree that we act out our personal issues in markets, we can't be fully focused on those markets.
A summary of Freud's view would be the dictum that those who fail to learn from history are condemned to repeat it. It is our repetitive patterns across situations of uncertainty and gain/loss that can take us away from doing what we know to be best.