From Bowlby & Ainsworth: What Is Attachment Theory?:

There are four patterns of attachment, including:

• Ambivalent attachment: These children become very distressed when a parent leaves. Ambivalent attachment style is considered uncommon, affecting an estimated 7–15% of U.S. children. As a result of poor parental availability, these children cannot depend on their primary caregiver to be there when they need them.
• Avoidant attachment: Children with an avoidant attachment tend to avoid parents or caregivers, showing no preference between a caregiver and a complete stranger. This attachment style might be a result of abusive or neglectful caregivers. Children who are punished for relying on a caregiver will learn to avoid seeking help in the future.
• Disorganized attachment: These children display a confusing mix of behavior, seeming disoriented, dazed, or confused. They may avoid or resist the parent. Lack of a clear attachment pattern is likely linked to inconsistent caregiver behavior. In such cases, parents may serve as both a source of comfort and fear, leading to disorganized behavior.
• Secure attachment: Children who can depend on their caregivers show distress when separated and joy when reunited. Although the child may be upset, they feel assured that the caregiver will return. When frightened, securely attached children are comfortable seeking reassurance from caregivers.

The Lasting Impact of Early Attachment:

Research suggests that failure to form secure attachments early in life can have a negative impact on behavior in later childhood and throughout life.

Children diagnosed with oppositional defiant disorder (ODD), conduct disorder (CD), or post-traumatic stress disorder (PTSD) frequently display attachment problems, possibly due to early abuse, neglect, or trauma. Clinicians suggest that children adopted after the age of 6 months have a higher risk of attachment problems.

While attachment styles displayed in adulthood are not necessarily the same as those seen in infancy, early attachments can have a serious impact on later relationships. Those who are securely attached in childhood tend to have good self-esteem, strong romantic relationships, and the ability to self-disclose to others.

Children who are securely attached as infants tend to develop stronger self-esteem and better self-reliance as they grow older. These children also tend to be more independent, perform better in school, have successful social relationships, and experience less depression and anxiety.

From What Each Attachment Style Needs From Their Partner:

If you are among the lucky ones, you were handed a Secure attachment in childhood — this is the Gold Standard that offers security, trust, autonomy, self-direction, self-love, boundaries and self-respect. Your self-identity is solid. Those who develop a Secure attachment in childhood, usually carry it with them through adulthood.

They are taught their value, to value others and the importance of having emotionally available relationships.

Then, there’s the rest of us…

Anxious Attachment. An Anxious attachment is identified by the “pull”. The “pull” is usually pretty obvious — demands to spend more time together, complaints that they feel neglected or unheard, or tears and arguments are common.

However, when manipulative tactics are used, it can ruin it for everyone (Secure attachments, too) because it plants the seeds of suspicion, doubt and distrust. It’s always our best bet to work on our own needs (trust issues, safety/security, self-esteem) first — before taking on a relationship and the needs of others.

The two things an Anxious attachment style needs from their partner are: to feel heard, and to trust them,

Avoidant Attachment. An Avoidant attachment is identified by the “push”. They may not be overtly pushing away; the push can be subtle such as burying themselves in work, gaming or hobbies to avoid intimacy and communication. Subtle pushing can go on for as long as they’re avoiding the needs of the relationship in order to meet their own.

To an unsuspecting partner, they may not realize the signs because they may be out of touch with their own needs, which can keep the “push” in full effect.

Pushing away is based on Self-preservation and will often start when engulfment is triggered, which usually surrounds emotional intimacy, commitment, or if they feel vulnerable emotions (fear, love, sadness).

Two things an Avoidant attachment style needs from their partner are: space and privacy.

Unfortunately, their two biggest needs are challenging to provide. Because of the “pull” partners they are attracted to, many with an Avoidant attachment can trigger distrust in their partner based on their behavior.

Disorganized Attachment. A Disorganized attachment is identified by both the “push” and the “pull”. Those who have a Disorganized style often suffered repeated early life trauma including neglect, physical, emotional and/or sexual abuse. They have deep unmet needs and are terrified of being abandoned and engulfed.

On the one hand, they want intimacy and to feel loved because many haven’t experienced it. On the other hand, their fears run deep and affect how they engage in relationships. They love deeply, and they fear deeply

They require many needs being met, in both Anxious and Avoidant styles, but have two main additional ones: stability, and patience.