David was 19 when I met him in therapy, three months after finding out that the stories his mother had told him about his father, from the age of eight when their relationship broke down, were untrue. These included allegations that his father was abusive towards his mother and that he never really loved her or David. Such stories led to David refusing to meet his dad on his allocated days and, when forced to, remaining sullen and refusing to speak. Over the months that followed the separation, David recalls his father desperately trying to explain that such allegations were untrue and telling him that he loved him. David felt hurt and angry, as well as guilty spending time with his dad, knowing that his mum was feeling sad and lonely at home. By his early-teens, David was barely seeing his dad and had lost contact with all of his extended family from his father's side. In essence, David didn't just lose his father but an entire family of grandparents, aunts, uncles and cousins.

The above is one example of parental alienation, a process by which one parent attempts to cause their child to reject, fear or avoid contact with the other parent. This most often occurs during separation or custody battles but can also occur within intact families and may include a variety of different tactics. Some examples include:

• Blaming the other parent for the breakdown of the relationship;
• Moving away so sustaining a relationship with the other parent is difficult;
• Telling the child that the other parent dislikes him/her or doesn't want contact with the child, despite the alienated parent trying to make contact;
• Punishing the child for talking about the other parent in a positive way or expressing a wish to see the other parent. Punishment may include withholding love, silent treatment, and so on;
• Convincing the child to make a false report against the other parent, such as abuse; and
• Restricting the time the child spends with the other parent or even defying court orders.

So, what kind of person tries to alienate their child from the other parent, keeping in mind how damaging it is for the child and the parent being targeted? Although a particular profile doesn't exist, a person carrying out parental alienation is often experiencing deep pain and anger towards their ex-partner, may fear losing their child as part of a custody agreement or may be seeking revenge for infidelity or for ending the relationship. Often, the alienating parent may be emotionally unstable or have borderline or narcissistic traits.

As you may imagine, the impact of parental alienation is quite devastating and can impact a whole family system. The alienated parent is likely to experience a huge sense of loss at not having contact with their child, as well as anger and helplessness if their attempts to seek contact are repeatedly thwarted. For the child, however, the results are even more devastating. Children may feel sad, lonely, confused and rejected. They may have questions such as "why does dad/mum hate me? Why won't my dad/mum call? Is it true that dad/mum never loved me?" They may feel guilty at spending time with the alienated parent, feeling disloyal towards the other parent. In the long-term, alienated children experience low self-esteem, difficulty trusting people and a range of other issues, blaming themselves for being unloved and rejected by the other parent, even if this was not the case.

Losing or having reduced contact with the alienated parent also leads to the child losing relationships with extended family, such as grandparents, uncles, aunts and cousins. Not only can this be very painful for the family members, but the child is robbed of what may be very positive and supportive relationships throughout their lives. The child doesn't lose just one parent but a whole family.

Apart from the personal costs of parental alienation, on a wider level, alienation is difficult to prove. Likewise, it's difficult to disprove if you're being accused of alienation. The legal issues are beyond the scope of this article. However, if you believe your partner or ex-partner is trying to alienate you from your child, don't retaliate by talking negatively about the other parent to the child and don't take out your anger on the child. Instead, continue to express positive feelings towards your son/daughter, telling them you love them and enjoy spending time with them. Be careful not to burden them with details of how the experience is impacting you, since the child may already be overwhelmed with the other parent's emotions, and their own. It may be useful to seek legal guidance from a lawyer with experience in such cases. Also, since parental alienation can have such a detrimental impact on wellbeing, it may be wise to speak to a mental health professional, such as a psychotherapist or counsellor. This will enable you to feel supported during this difficult and challenging time.