Attachment theory is very interesting to me. Yes, early childhood years make a difference, but the neuroscience talks about formation of neurocircuitry all the up to around 22 years old. I can't quote the phenomenon, but that is the time when the formation stages start settling down. The secure attachment style is mostly formed by family and in early stages through teenage years. The good news is that the brain can rewire even in later years. This is called neuroplasticity. Bad relationships cause damage and self fulfilling prophecies. Good "healthy" relationships build back the secure attachment circuitry and make relationships more fulfilling. Emotionally absent parents have a strong influence.