It seems implausible that destroying the love a child has for a parent can be harmless. It is possible that children subjected to alienating behaviour may suffer the following characteristics, as they are growing up:
1. A nagging and gnawing feeling of loss for the other parent that may never be reconciled while the alienating parent has a hold on them.
2. Unresolved issues about relating with the opposite gender, often represented by the alienated parent. For example, a girl who grows up to be a woman without her father may often have issues with her relationships with men in which she attempts to actively resolve the incomplete relationship with her father. This is often destructive.
3. Relationship conditionality, a belief system in which a child feels that it is valid to use a relationship solely for their own ends. After all, they saw their parents do it!
4. Feelings of blame and responsibility for the family breakup, and for the entrenched conflict between their parents.
5. Severe depression, depression may occur secondary to being highly self-critical. Since the validation they would otherwise receive from their parents has been converted into playing a survival game in an emotionally militarised zone between them.
6. Severe anxiety. Such anxiety is secondary to constantly anticipating their own failure through poor self-esteem. Anxiety may also be secondary to hyper vigilance about relationship conflict in which they are either feel they are to blame or from the fear that they may be caught up in it.
7. Ambivalent or avoidant attachment or relating styles. Alienated children learn that relationships are unsafe and that people cannot be trusted, perhaps they cannot even trust themselves.
8. Low self-esteem. Alienated children do not have the validation from both parents that is required to build a strong sense of a worthwhile self. Girls could become more prone to eating disorders and other self-harming behaviour. Boys could become more prone to rage (unresolved grief), depression and suicide.
9. Personality disorders. These can be extremely serious and permanent distortions of personality, which are often mirrors of the alienating parents mental health issues. Narcissism, paranoia and borderline processes are possible in which an alienated child may grow up to be an adult who constantly seeks the adulation of others without being able to relate with them, is constantly preoccupied with the possibility that people are conspiring in various ways against them, or have self destructive behaviours and a highly polarised and paradoxical relationship style (‘I hate you, don’t leave me’).
These characteristics may also be due to many other conditions and situations and should not be used nor are intended to be used as a diagnostic guide.