As I write this, I'm in a fitness first gym taking drinks in the lounge area. The place is so pleasant with lots of wonderful facilities and staff. Yet when I'm on the treadmill or walking around thinking of seeking assistance, I'd sort of catastrophize: "What if the treadmill I'm on gets derailed?" "What if the staff just looks at me or refuses to help or leaves me alone?"
My overreaction in me was out of proportion to the reality of my external situation. During my childhood onwards to adulthood, I was traumatically abandoned emotionally by my own father and mother who eventually separated and lived different lives. They were not there even physically during my most distressing times growing up. Now my obsessive thoughts in the gym centered on not being supported or given needed attention -- being left alone or behind.
Much of neurological research supports what every psychotherapist from Sigmund Freud until this modern day knows firsthand: the compulsion to repeat. Brain researchers explain that severe overreactive responses stem from enlarged "neuronal imprints" in the brain from previous stressful or traumatic experiences. Such distort how a person experiences aspects of subsequent painful stimuli that other people may not be capable of noticing.
This supports the concept then of "the more difficult childhood was, the more difficult adulthood is." When contamination in the foundations or core materials are embedded in childhood, it serves as an overly sensitive "filter" shaping one's thoughts, feelings, and behaviors towards subsequent life events. It's kind of like a tape recorder whose button is still on and therefore stuck. The brain responds to what's not existing on the outside because a contamination is still existing on the inside.
Psychotherapy rests on the principle that ancient wounds, deprivations, or pains have been numbed out or buried alive, and need to be worked out. Until they are worked out and sufficiently healed, they'll continue to be acted out, acted in, or projected onto others. It's unfinished business that needs expression to heal compulsivity which continues to unconsciously relive old wounds and life-damaging patterns.