Trauma in attachment can begin in utero, not only through alcohol and drug consumption but through the stress of an un-welcomed pregnancy. Once born, infants quickly use their senses and emotions to determine who he or she can trust to meet their needs. Newborns are already wired for the sound of their mom's voice and will immediately connect the smell, touch and taste of mom to the sound of her. It is at this time, infants begin forming trust and an attachment as their primary caretaker continues to meet basic needs emotionally, physically mentally and spiritually. If this trust is interrupted through adoption, extended hospitalization or abuse, this throws their developing brain into the fight, flight or freeze state. This experience is hard-wired and the child learns that he or she cannot trust others for met needs. This sets them up to try to meet their needs on their own and they will try whatever gets a response from others or a need met. Eventually, this may take on the form of "the perfect child" or the child who always is getting into trouble. These are coping skills learned and used as children but as they grow into adults these coping skills hinder them from authenticity in relationships.
I saw this in nature once where after a bad storm a friend of mine found a very young kitten scared and hiding in her garage. Knowing my family was wanting a kitten she passed Valentino on to us. We fed him by bottle and loved on him. However, as much as we tried to love on him he never wanted to be pet. One day he discovered my daughters fuzzy blanket and began suckling it. From then on he would seek out that blanket and suck on it for long periods of time, all the while purring. It was the only time that he would allow us to pet him. I believe that since he went through the trauma of losing his source of safety and basic needs he couldn't trust or "connect" with us. He continued to try to meet his needs through a blanket but it just couldn't meet the need that was lost. He was stuck.