"As with any anxiety, or manifestation of an anxiety, responding with irritation is not helpful," says Dr Angharad Rudkin, a clinical psychologist at the University of Southampton. "At its root, a holiday represents a change and it's not uncommon for humans of all ages to fear and resist difference. As adults, we're generally better equipped to assimilate change, and to make sense of time frames — children, especially younger ones, can't be expected to have the same reasoning skills."
Adults may also contribute to the problem: how relaxed are they in the lead up to a holiday? Frantically hunting for passports, fretting about packing, arranging a dog sitter ... when these things are occurring, children are likely to feed off the stress and start simmering with anxiety. It links the holiday with feelings of unease, which may then be exacerbated by the simple fact of being away from home.
"Routines prop children up; they thrive on familiarity and structure," says Rudkin. "Staving off homesickness can be helped by keeping up routines as much as possible, even if only for the first few days, to help kids settle in." The younger children are, the easier it is to transfer their comforts — a toy, a blanket, a favourite pair of pyjamas, all of which can help to quell feelings of uncertainty in a new environment.
Hills agrees that maintaining routine, especially around bedtimes, can be a helpful tool to quell feelings of separation from home, but she warns against going too far in recreating a comfort zone for kids.
"Taking children out of familiar surroundings helps them to learn resilience," she says. "It teaches them that there is a wider world out there and it's all about adapting — after all, things change all the time: that's life."
The best way to teach children to accept and even enjoy change is by modelling it yourself, she says.
"Acknowledge something that's a regular occurrence in your everyday life that's missing from the holiday and put a positive spin on it," she advises. "Say something like: 'I usually have a cup of tea in the morning but I'm really enjoying the fresh juices here instead,' but avoid saying: 'Oh darling, I'm really missing my morning cup of tea too — but don't worry, only five days until we're home again'."
For older children, Dr Rudkin says, homesickness is more likely to be a case of "friendsickness" — missing their friends and feeling anxious about what they are missing out on while away. Talk, in advance of the holiday, about how to manage the situation — perhaps by using social media (within reason) to stay connected, or by taking a complete break from it.
Telegraph Group Ltd