A parent looks at their child’s first year report card. It is peppered with C and D grades and they know their 13-year-old son didn’t try his best. In another home, after 10 years of happily playing team football, a 15-year-old girl announces that she wants to give it up. Her parents feel that she just can’t be bothered putting in the effort and would rather be on her phone.

So, why do previously energetic and interested children seem to lose the motivation to do their best and start opting out of things in their teenage years?

It’s a myth that teenagers lack motivation; they will go to the ends of the earth to track down a concert ticket, spend four hours getting their hair and make-up just right or play an eight-hour Fifa marathon. The problem is that what motivates them is not necessarily what you, as a parent, think is important. So how do you help them channel their natural motivation into doing things that are not high on their current list of priorities?

Let’s first look at the teenage brain and the role it plays in their motivation. Brain development generally follows a natural sequence with increasingly complex thinking skills emerging throughout childhood. However, during adolescence, there’s a slight glitch in the sequence.

The regions associated with reward and social approval (centred on the amygdala) go into overdrive, while the areas associated with reasoning and thinking through the consequences of actions (in the frontal cortex) lag a little behind. This helps explain why teenagers are so self-centred and focused on thrills in the “now” and often poor at thinking through the logical outcomes of their sometimes hare-brained ideas.

It also explains why they tend to make choices which bring an immediate sense of wellbeing and impress their friends rather than making more sensible choices with longer term rewards. The good news is that their ability to prioritise, plan, sequence, initiate, rationalise and make informed decisions (the “executive skills”) improves as they reach their late teens. In the meantime, you need to remain closely involved and be prepared to override any blatantly bad choices.

Match their abilities

It’s important that expectations and demands are pitched at their abilities. If the task is too easy, they will be bored and opt out. If it’s too hard, they will become disheartened and give up. In the case of the 13-year-old boy, it turned out that he was struggling with the number of subjects in secondary school and was finding it hard to make new friends. He hadn’t lost motivation; he was just overwhelmed.

Motivated and persistent children generally pick up these traits from parents, teachers and coaches. If you want your child to do their best at sports, get out there yourself and play or coach.

If you want them to do their best in school, make sure they see that you too try your best in your own work and life. Because those executive skills are still developing, you need to support them with planning, sequencing and organising and lay out the steps required to reach a goal.

A colleague came up with the “Hidden Ladder Syndrome” to explain why so many children of successful parents lack drive and motivation. The idea is that if you don’t explain the “ladder” to your success and just hand them everything on a plate, they have no idea how motivation and hard work are linked to success.

Sleep is often overlooked as a reason why children underperform or lack motivation. Teenagers need about nine hours of good quality sleep and a regular bedtime; going to bed at 3am or 4am at weekends and getting up for school at 7am on Monday can create a type of jetlag.

Many teenagers now sleep with their phone on and one ear cocked for the ping of an incoming message. This disrupts their deep and REM sleep patterns, which are both vital for physical and mental wellbeing. The reason they can’t focus in school or play sports is because they’re exhausted. No child or adult should have their phone in their room at night unless they’re on call.

Rewards and incentives are powerful motivators. While it would be wonderful if every child was motivated purely by the sense of achievement they gain from a task, very often, and especially if you’ve got a teenager struggling with something specific, a more structured reward plan can help get them over the hump. For instance, with the teenager wavering about football, she was given €10 (she also gets €10 pocket money regardless) for every week she attended both training sessions, with the clear understanding that she could give it up if she was still unhappy after three months.

Any reward system requires parental effort and consistency, and if teenagers are already allowed everything they want – phone credit, clothes, no limits on socialising or screentime – regardless of their behaviour, it will never work.

Far from being artificial and contrived, planned reward systems (which do not have to involve money) teach them the real-life skills of reward following effort and the innate satisfaction of having earned something.

If there is a sudden and unexplained drop in your child's motivation or achievements, you should investigate it further. Mood, anxiety or problems with friends can seriously affect a child's confidence and motivation.

First try to talk to your child and their school but, if you’re still worried, bring your child to your GP.

Dr Sarah O’Doherty is a clinical psychologist.