Q. My 13-year-old daughter spends a lot of time on social media and often seems anxious, depressed and moody. I don't know whether it's just because she's being a 'normal' teenager, or whether her mood is negatively affected by her social-media use. She's not easy to talk to about it - what can I do?

A. Dr Luke James, medical director of Bupa UK, says: "With so many young people signing up early, even lying about their age and keeping accounts secret from their parents, it can be hard to intervene or get a full picture of what's going on with your child.

"But you're right to be concerned - a new Bupa study has shown symptoms of mental ill-health, such as anxiety, stress, irritability and low self-esteem, are all more common in teens who use social media. And girls are more likely to be affected than boys.

"It's really tough for parents to protect their child from things online that could harm their mental health. And while using social media can be a useful way to stay in touch with friends and family, the desire to stay connected 24/7 can interfere with activities that build mental resilience in children, like getting enough sleep and exercising. On top of this, teens we spoke to said social media distracts them from schoolwork or revision, contributing to academic pressures and anxiety.

"We know many teens are aware of the negative impact of social media and some have even taken steps to limit its impact - for example, blocking people who made them feel bad, increasing privacy settings or even taking a 'digital detox'.

"It's important to broach the subject of mental health with your daughter. Rather than telling her you're worried, which could put her on edge, simply asking how she is can be a good way to get a dialogue going. To get the most out of the conversation, stay calm, listen, and acknowledge her responses, and be wary of undermining her feelings by saying things like, 'Social media doesn't matter', or, 'There's no need to worry about that'.

"Every child is different, so using your judgement is key. It might take a few goes to get her talking, or she might prefer to talk to another relative or family friend, but either way it's really important to get a dialogue going.

"Just like physical health, mental health can fluctuate day-to-day, and it can be tricky to distinguish between teenage mood swings and the symptoms of a mental health issue. But if you're still concerned about her mental health, speak to a medical expert, such as your GP.

"There's no health without mental health and, if you're worried about your child, this can have an impact on the whole family. That's why Bupa has produced a guide (which you can search for on our website) for parents to learn more about children's mental health."