Looking at that lanky collection of knees and elbows propping open the refrigerator, you have to wonder what happened to the cheerful little boy that zoomed around the house pretending to be Ben10.
And the last time your daughter threw herself onto the floor and held her breath until she turned blue was when she was three. Except now she's sixteen and threatening to do it again because you won't buy her a new phone. Why has this stormy emotional behaviour come back, and why do you have a distinct feeling of déjà-vu?
It turns out that both the toddler and teen phases of brain development have a lot in common. Both phases are characterised as rapid developmental stages when new connections are being forged in the brain and major changes are taking place.
Just like the spurt toddlers go through which takes them from tottering on unsure feet to being able to run and jump, and increases their vocabulary 100-fold within a year, teens are going through external and very deep internal changes.
One of the last maturing stages in the brain is the coating of nerves with a fatty material named myelin. This myelin sheath wraps around brain neurons and allows electrical impulses to travel quickly and efficiently.
Myelin develops in the more primitive areas of the brain initially and then gradually moves to areas of higher function, with the frontal lobes maturing last. Full myelination is probably only reached at in the early 20's.
According to Dr Kevin Rosman, neurologist: "The frontal lobes are only fully developed towards the end of this period. These have to do with attention-focussing, as well as reading of and response to emotional situations. This is probably one of the important reasons why adolescents are "up and down" emotionally".
The up and the down side
As the brain's development is still happening right into the early 20's, this also implies that the brain is more susceptible to the effects of toxins, for example alcohol, nicotine, and other recreational drugs at this age, when the long-term effects may be more serious than at a later stage, says Dr Rosman.
But the news isn't all perilous. Dr Rosman says: "At any age, but especially at this rapid development stage, new connections in the brain are made by practice. This will include things such as reading, and exposure to new healthy experiences. At this age, for this reason amongst others, adolescents should be exposed to a wide variety of experiences, especially intellectual ones. This, theoretically at least, will help them get balance in their own minds later on, when they can draw on experiential resources to evaluate new situations."
Which means that fostering sound lines of communication, and taking time to do interesting things with your teenager will make less space for tantrums, lay down some very useful skills and open up interests that will last them a lifetime.
Dr Neil McGibbon, psychologist, says: "Parents expecting adult responses and reflection from adolescents are somewhat misguided in their expectations. Adolescence is a process in which the child moves into adulthood, and the process is far from complete at 14 or 16 years of age."
"It is noteworthy that research on the adolescent brain suggests that, due to brain development, emotional reactions take precedence over rational thought. Parents will recognise this as the sometimes explosive emotional reaction to a request that has been denied. At this point parent and teen will be on very different pages – the adult rationality versus adolescent emotionality."
In moments like these, it's important to realise that your teen's reasoning faculties have been overrun by emotion. Rather give an age-appropriate version of the toddler's time-out, and have this discussion when tempers have cooled and emotions have quietened down.
Sleeping on it
Another parallel drawn between toddlers and teens is the change in sleep patterns. Due to the major changes happening within and without, teens need more nap time.
Dr Rosman says of the sleep issue: "although the sleep schedule may not be the same as their parents, adolescents probably require more sleep now than at a later stage. Sleep is particularly important for forming new memories, and a lack of sleep will likely have a detrimental effect on school performance. Lack of sleep has also been well demonstrated to affect mood - so too little sleep is going to worsen an already labile young person in terms of mood control, aggression and rebellion."
"During adolescence there is a stage where the sleep tends to start later at night and last later in the morning. This is why they drive their parents crazy staying up all night, and sleeping all morning. It also means that they are likely to learn and concentrate worse in the morning. In a recent study from the USA, when a school elected to start classes later, there was an average 7% increase accross the board of the marks!" adds Rosman.
Knowledge is power
When trying to get sense out of an eye-rolling 15-year-old with a phone glued to her ear, or battling to wake your 14-year-old son in time for school, don't be discouraged – your children haven't been snatched and replaced by aliens, all is exactly as it should be. Not only is this behaviour normal, it's pivotal to your child's healthy development. Now that you've got a window into your teen's mind, it's going to be easier to help him navigate the transition from child to adult.
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Any questions? Visit the Teen Centre or write to the Teen Expert
(Joanne Hart, Health24, October 2010)