If you notice your teen's usual friend(s) are no longer calling or inviting them over. If you ask your teen about his/her friend(s) and they reply with something like 'I have no friends', then that's a red flag and you need to find out more. Vanishing friends can be an indication that bullying is taking place.

Look out for significant changes in your teen's behavior and personality. Teenagers who are being bullied typically appear anxious, clingy, withdrawn or sullen. They also tend to appear sad, moody, depressed or teary, especially after school or after being online. You should also consider it a warning signal when your teen starts to suffer from low self-esteem, starts to blame themselves for things and start to voice out how they are not good enough. Bullying, whether emotional or physical, is a likely cause of this.

Teens who are being physically bullied tend to come home with constant injuries: unexplained cuts, bruises and scratches. You might also notice they tend to come home very hungry even after being given a lunchbox to school and pocket money for snacks. A likely cause of this hunger is that they are being bullied for their food and money.

If your teen suddenly starts to have trouble sleeping, if he/she seems to be having more nightmares, if you notice he/she sleeps more than normal or cries himself/herself to sleep, these indicate that something is amiss with the child and it can be caused by bullying. Quality sleep is crucial for a healthy lifestyle; sudden changes in your teen's sleep patterns should be investigated.

When your teen, whose grades are known to be consistently good, suddenly starts performing badly, you should look deeper. When a child is being bullied they usually find it difficult to focus on schoolwork, as a result their grades tend to drop. You should also occasionally ask your child in direct and indirect ways if they like school. If their response is along the lines of them 'hating' school, dig deeper, bullying might be the cause.

If your teen stops doing things they once loved to do, if they lose interest in their favorite activities and start skipping school-related or social activities involving their peers, even going as far as deceitfully reporting these activities have been cancelled, you need to gently and wisely find out why. Bullying is a likely cause of this evasiveness.

If your teen, who typically isn't careless with his/her possessions suddenly starts to lose personal belongings and property, it might be a sign that the child is being bullied out of his/her possessions. Don't be quick to dismiss this as irresponsible behavior, investigate, dig deeper to understand the cause of this sudden carelessness.

If your teen starts to have intense emotional reactions towards people, conversations or activities, it could be a sign that they are holding anxiety for or around these things or people due to either physical or emotional bullying. Dig deeper to find out.

If your teen suddenly starts to withdraw from family, talking and interacting less than usual with family members, it could be a sign that something is amiss. If the teen has siblings and suddenly starts acting out against them, shouting or reacting aggressively to them, this could also be a more prominent sign of bullying. It should not be ignored.

Teens who are being bullied often develop a lack of assertiveness and ability to stand up for themselves. They develop a victim stance that sees them walking with their heads down, talking themselves down and being unwilling to comment or speak their mind. This is one of the effects of prolonged bullying and at this stage patience is needed to help the teen build back confidence.