Signs of mental health problems in teenagers and children are sometimes dismissed as angst, but a recent Government-funded survey has revealed why we should be taking the issue much more seriously.

[Read more: 7 simple ways to improve your mental health]

At the age of 14, a quarter of girls and one in 10 boys show signs of depression, researchers from UCL Institute of Education and the University of Liverpool found. The causes include stress, body image issues, bullying and social media pressure – all of which are typically experienced by teenagers and children in day-to-day life and may have a greater effect than you think.

Those from poorer or mixed ethnic backgrounds have a greater risk of showing signs, the survey of more than 10,000 children taking part in the Millenium Cohort Study found, while girls are more likely to suffer than boys.

Emma Saddleton, helpline manager at children’s mental health charity Young Minds, says: “Most young people experience ups and down during their teenage years and occasionally will feel down or upset by things going on in their lives. They might be adapting to a change in their family or school life, or just trying out new emotions, and will generally grow out of worrying behaviour.

“But some young people feel sad, lonely, down, anxious or stressed for longer periods of time to the extent that it can affect their everyday lives and can prevent that young person from doing things they would normally do.”

For early intervention, you should look out for the following signs:

1. A lack of motivation or interest

One sign of depression is a severe lack of motivation. This might come in the form of caring very little about their grades, showing little interest in hobbies, or even going out to see friends. Make note of what they’ve been enthusiastic about before, but may not be now.

A young woman in a hoody sitting down with head on knees (Thinkstock/PA)

2. A feeling of intolerance or irritation

Intolerance or irritation can be shown in a few different ways. They might cope by snapping or causing arguments more often than usual. Perhaps they’ve suddenly shown a sudden dislike to something or someone for seemingly no reason or frustration builds much quicker than it used to.

[Read more: 7 simple ways to support your child’s mental health]

3. A feeling of hopelessness or helplessness

Look out for indications of helplessness in the things your child or teen says. They might think that nothing they can do will help improve their grades or improve relationships with friends. In some cases, they may become more reckless when thinking their actions no longer have consequences.

A girl looks through her wardrobe of clothes (Thinkstock/PA)

4. Lack of self-esteem

A lack of self-esteem can be evident in small actions that might be mistaken for typical teenage habits. Your teen might fret a lot over their outfits or appearance, constantly going back in to their room to change. They might worry over small outings such as going over to the shop for a pint of milk or meeting family friends.

5. Difficulty in making decisions

Although many people have trouble with making decisions, in an extreme case, this could be a sign of depression. Look out for signs of becoming easily frustrated or tearful when faced with a choice or decision.

A girl looking at her mobile phone with coat over her head (Thinkstock/PA)

6. They are no longer finding enjoyment in life

If your child or teen lacks excitement for things they would have previously enjoyed for a long period of time, this could be a strong indicator of depression. They might not care for an upcoming party or a meal they love. Become aware of how often they smile or laugh when watching TV or scrolling through their phones.

7. Changes in patterns of life

Other signs that may be easier to spot include changes in eating and sleeping habits. If your child or teen is eating or sleeping significantly more or less, it might be time to take the symptoms more seriously.