Hi welcome to the site, researching attatchment theory will help. In addition, there's good reading on this page
Maternal & early years on NHS Scotland
If you have the Cache handbook read through pages 374/5 where it looks at emotional security, the need for trust to feel emotionally secure and the impact of poor attachments which might lead to anti-social behaviours, mis-trust, aggression towards others. The effect on mental health and how children can be less inclined to explore their environments where poor attachment issues are present, anxiety & depression and how relationships are less positive where poor quality attachment is experienced in the first 6-12months of a babys life.
Best wishes
Best wishes