Dear Annalisa

My 11-year-old sister refuses to sleep on her own, and still sleeps with our parents. She says that she’s too scared to sleep on her own. I’ve asked her many times why she doesn’t sleep by herself. She always says that she’s scared and she doesn’t want to sleep by herself in her room. She says the room is haunted and she saw our dead grandfather’s face once. I also have a feeling that something is wrong with that room but when I offered her my room she said she doesn’t know if she’s able to sleep on her own.

My parents and I have tried many methods to get her to sleep by herself such as leaving the lights on, leaving the door open, etc; however, she always ends up going back to my parents’ room. She slept on her own until she was eight, but since my parents let her sleep with them she hasn’t been able to sleep on her own. Is it a phase?

My parents and I are very frustrated. Please help.

The answer to your question is in your letter. Your sister sleeps well when she is with you or your parents. It won’t always be like this. Whatever it is that is worrying or frightening her will pass, she’ll grow up and find it embarrassing to sleep with her parents, or she won’t want to share a room with you any more.

I don’t know why this is happening. I think if you believe in ghosts you believe you might hear or see them. I know that, when I was in my late teens and my sister had left home for university, I got really anxious about bedtime and imagined all sorts. But, looking back, this was linked to anxiety, although I didn’t realise it at the time.

It may be something that’s frightened her at home – a film, maybe you were burgled once? Or she may be anxious about something outside the home – is everything OK at school? What happened when she turned eight and started going in to your parents’ bedroom?

Also, she may actually be less afraid for her own welfare, as she is concerned for yours (yours being you/your folks). The reasons may be myriad, complicated, and she may not know them herself. It may be something physical or psychological or a mixture of both. The point is, if your sister were worried about something during the day and craved company, you wouldn’t banish her to a room on her own, would you? (Would you?) And in fact we have an even bigger, primal need to feel safe when it’s dark.

What’s important is that you all feel secure and safe and get some sleep. If she’s not sleeping, it will affect her ability to learn (sleep is when we consolidate what we’ve taken in during the day) and her emotions. Lack of sleep mostly affects the part of the brain that deals with positive or neutral emotions – the hippocampus. And it least affects the part of the brain that processes negative emotions – the amygdala. Sleep-deprived people can therefore remember bad things/memories more readily than good ones, which can lead to further anxiety/depression/inability to sleep.

The other thing that may be happening is that she’s not as tired as she once was at her usual bedtime. As you enter puberty, your body clock shifts forward, which means that you don’t start producing melatonin (the sleep hormone) at sufficient levels to send you to sleep until a couple of hours later. This is also why teenagers are often hard to rouse in the morning as melatonin levels can still be high and they want to sleep.

Maybe you could try to help your sister with winding down at night. No blue light (no screens, these interfere with melatonin production), a hot milky drink (magnesium in milk helps to relax us), a gentle chat? You might even look back at these days fondly.

I presume you are older than she is (either that or you are an incredibly articulate 10-year-old). And I wonder if part of you might be resentful of the time she’s getting with your parents? Does it bother them?

I think it’s great you are concerned, but I wonder if part of you is also a bit annoyed? I’m not saying you don’t have a right to be. But you may need to look at why. Perhaps you feel that your sister is given more attention than you are? Perhaps this harks back to her arrival in some way and you feel she gets in the way. All of this may be way off the mark, but if you recognise it, it’s completely normal to feel like that.

The best way to help your sister is to let her sleep in company. This phase will pass.

This article first appeared in The Guardian on 7 February 2015.