One moment your tween wants to cuddle with you on the couch and watch TV; the next, she's giving you the hairy eyeball for asking who she's texting. Who is this changeling that has replaced your sweet child?! Blame biology (in part, anyway).

Brain changes
As kids reach puberty, they experience a number of physiological changes. Besides the obvious physical developments, things are brewing on a hormonal level and their brains are still maturing. Production of the sex hormones, both male (androgens) and female (estrogens), increases during adolescence, triggering changes in the brain systems, including those associated with cognitive processing and emotion, says Cecilia Flores, associate professor in the department of psychiatry at McGill University in Montreal.

"The prefrontal cortex is unique because it continues to develop until early adulthood and it undergoes dramatic changes in the organization of neural connectivity during adolescence," says Flores. She adds that, when you combine a developing brain with fluctuating hormone levels, short- and long-term behavioural effects, such as changes in mood and emotion, are likely outcomes.

But hormones are only a piece of the puzzle. "There's so much happening in the early adolescent years; we can't give it an assignment like ‘This is 20 percent hormones and 80 percent cultural,' " says Alyson Schafer, parenting expert, author and psychotherapist in Toronto. What is certain is that the combination of hormonal shifts, neurological development, physical maturation and evolving social dynamics packs a wallop.
 
"Early adolescence is a stressful time," says Schafer, who notes that many children in this life stage are still developing the skills to recognize, manage and express their emotions. The result is often a surly or teary tween (and sometimes both in the span of a few minutes).

Sunny to sullen
"I was expecting moodiness from my son, but what surprised me was the age at which it started," says Samantha*, Toronto mom to a daughter, 17, and sons aged six and 14. At 11, her oldest son began lashing out and mouthing off at Samantha and her husband, the stepfather he'd always been close with.

The transition from a well-behaved, happy boy to a sullen teen was upsetting, she says. She even had her son visit their family doctor to ensure that depression or another issue wasn't at play. "We knew the teen years would involve our son becoming more independent-minded and peer-focused, and that he wouldn't want to spend as much time with us, but we didn't expect him to be so mean. He said some really cruel things. Even today, everything I do is ‘stupid,' and his stepdad can't do anything right, either. He thinks we know nothing, and he argues every little point."

Not cool
Samantha suspects social expectations are part of the issue. "There's such a big break between being a ‘little boy' and a ‘big boy,' " she says. "My six-year-old sees his friend and runs to give him a big hug, but my older son can't do that with his friends because that would not be cool."

Samantha has a number of friends who are struggling with similar issues at home: sons who shrug away from hugs or are no longer interested in playing street hockey or shooting hoops with Dad. Family relationships can be strained by the rejection parents feel.

Kim Rossos, another Toronto mom of three, uses the word "grumpy" to describe her two daughters, aged 13 and 15, at this stage. "They often put in their earbuds or hide away in their rooms or the basement to avoid us, or for privacy," she says. "I try not to take it personally."

Schafer's advice for parents of children who have hit adolescence? Establish some ground rules, then cut your tweens an appropriate level of slack. Remind them that bad moods are legitimate, but rudeness is not. "It's OK to say, ‘Take time to be angry, but come back when you can be more respectful of others,' " says Schafer. "You don't have to tolerate being treated disrespectfully."

From tween to teen
These tween years are a rite of passage for kids and parents alike and good prep for your child's next stage. "Your relationship is going to change," says Schafer. "When your kids are young, your main job is to be a disciplinarian, but as they enter their teen years, you become ‘sage counsel.' If the relationship is healthy, they'll continue to take your influence."

When it might be something more
Although tween moodiness is normal, be alert to signs of a deeper issue. If your child avoids friends, complains of stomachaches, misses school, oversleeps or battles insomnia, or neglects appearance to the point of unkemptness, he or she may be experiencing depression. If in doubt, see your family doctor. Start the conversation with the truth: "You deserve to feel better than you've been feeling, and I would like us to talk to a professional about it."

How to help your kid through this challenging time

- Offer hugs. And try not to be offended if they're occasionally shrugged off.

- Listen without fixing. "Giving advice shuts down the conversation," says Alyson Schafer, Toronto author and psychotherapist. Empathize instead: "Sounds like nothing went your way today!" or "Oh, no. That's embarrassing" are good responses. "Here's what you should do next time" isn't.

- Ask for a do-over if you tried the wrong tack the first time. If your kid is freezing you out because listening isn't your forte, apologize and say you're ready to lend an impartial ear. Don't force a face-to-face talk if your tween prefers another mode of communication; some tweens would rather text about a sticky situation. (Schafer once texted with her daughter for 20 minutes before being invited to talk in person.)

- Provide options for a cooling-off period. It could be walking the dog to get fresh air or soaking in a warm tub to help relieve stress.

- Accept that a relative or friend may be the preferred confidante.

*Name has been changed.

Check out these tips on how to raise an independent tween.

This story was originally part of "Feels Like Tween Spirit" in the June 2015 issue.             Subscribe to Canadian Living today and never miss an issue!