Physiological and mental changes in adolescence
Effects of puberty
Puberty is the rapid physical growth of bones and muscles and psychological changes, culminating in sexual maturity of bones and muscles. It begins from 9-12 for girls and 11-14 for boys.
1. They begin to be conscious of how they look
The increased hormone activity of an early teen begins to affect their height, weight, and emotions. Their physique changes and they become conscious of how they look. You may notice changes in hygiene and the way they assert what they will wear, hairstyle, and vanity.
2. Heightened sexual desire and emotions
The human brain is not fully developed by the time a person reaches puberty. Between the ages of 10 and 25, the brain undergoes changes that affect behavior the physiology. In teenagers, they experience sudden and rapid growth, triggered by the pituitary gland.
This gland located in the brain that secretes a surge of hormonal agents into the bloodstream, initiating a chain reaction to occur. Also known as the “master gland,” it affects their entire body, particularly their sexual development and emotions.
The pituitary is a small pea-size gland located at the base of the brain. This “master gland” releases a wide variety of hormones that is important in a teen’s physical and emotional development.
3. Increased desire for adventure
The circulatory and respiratory systems are mostly influenced during this development. Their muscles and bones grow significantly. Coupled with changes in their emotions, they have a strong desire for physical activity.
Activities like biking are encouraged because it feeds both their muscle’s demand and their quench to discover new things.
4. Increased brain capacity to understand and reason
As the brain develops during adolescence, the amount of “white matter” in the brain increases, while the “gray matter” is pruned called synaptic pruning. The brain appears to be destroying itself, but the pruning makes it more efficient due to increased myelination (insulation of axons or nerve fibers) and reduction of unused pathways (neurons). 
The brain should be well fed before synaptic pruning occur
The result of synaptic pruning helps improve the way they process data fed to them. Teens logic and reasoning improves. In short, you can no longer outsmart them, as if they’re little children.
you can no longer outsmart them.
However, pruning also means that there are certain “circuits” that the brain chooses to cut or retain. Children can absorb so much knowledge such as learning multiple languages, as compared to when they become adults. Any second language they learn before puberty will likely be retained. However, new languages taught in college will likely be forgotten unless spoken daily.
Therefore, learning things like foreign language, dancing, or music should be taught before puberty stage (or before High School).
“All these things should be taught earlier than they are being taught, that is one lesson we know about the pruning process,” says Dr. Dan Siegel, Clinical Professor of Psychiatry at the UCLA School of Medicine.
Learning things like foreign language, dancing, or music should be taught before puberty stage.
Synaptic pruning or Axon pruning starts near the time of birth and is completed by the time of sexual maturation (puberty). The “extra neurons” (cells that process and transmits information) are eliminated to improve the efficiency of neural transmission (brain signals). Synapse is a structure that allows nerve cells (neurons) to pass signals to another neuron. In puberty, synaptic growth spurts.
The “Dorsolateral Prefrontal Cortex” (DLPFC) covers the front part of the frontal lobe. The development of DLPFC affects a teenager’s motivation, mood, and general emotion.  The most significant change in the brain happens here. DLPC is involved in decision making and cognitive control. Children with Autism have extra synapses in Brain . Researcher Jay Giedd compares synaptic pruning from a block of marble that is sculpted to create a refined image.
DLPC is involved in decision making and cognitive control.
Important facts about a teen’s developing brain
1. It is the last part of the brain to mature or until age 24.
2. The Executive Function of DLPFC are the following:
● Overall personality of a teenager
Also known as frontal lobe has the “Executive Function.” It’s responsible for abstract reasoning and decision making.
5. Emotional vulnerability and rebellion
Teenagers at this stage of brain development have a better evaluation of risks and rewards. They have improved brain processes that lead to a better understanding of consequences. However, their “new found knowledge and wisdom” may also cause rebellion.
A teen’s logic is not the same as their parents. This may result in opposing views between them. Although the wisdom of parents will likely prove to be the sensible choice in making a decision, a teenager’s lack of life-experience may result in a “flawed logic,” creating conflict and rebellion.
Although they are less impulsive , they become more sensitive and vulnerable to words that parents use, which they often misinterpret. Parents should talk to teens with adult reasoning because they can already handle analytical thinking, but don’t expect immediate submission.
Parents should talk to teens with adult reasoning because they can already handle analytical thinking
Neurotransmitters or “chemical messengers” are chemicals that enable “neurotransmission.” Neurotransmission is important for the process of communication between two neurons. A neuron is a basic unit of the brain, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells.
Synaptic transmission relies on the availability of the neurotransmitter which simply means that the more neurotransmitter there is, the better the synapse (brain communication) occur.
1. Glutamate (Impulsivity) – An amino acid chain that influences the reward system and related behavioral traits like impulsivity. 
2. Dopamine (pleasure) – Associated with pleasure and attuning to the environment during decision-making. During adolescence, dopamine levels increase thus the balance of excitatory to inhibitory neurotransmitters and increased dopamine activity in adolescence have implications for the teenager’s risk-taking and vulnerability to boredom. 
Facebook and dopamine
Drug abuse among teens allows them to experience higher levels of dopamine. Likewise, if they get excited by having more “likes” than expected, on a photo they posted on social media, it triggers more dopamine levels causing them pleasure. However, this form of affirmation may lead to “fake life and may even grow horns, a new study show.”
This is one reason some people spend more time getting that perfect “selfie.” The more likes, the more dopamine, the more pleasure. Becoming obsessed with better responses in the form of “likes” can be a problem. Wrong use of social media, like Facebook, can be a form of addiction.
Wrong use of social media
3. Serotonin (Happiness) – Help regulate mood and behavior. Changes in the levels of the dopamine (neurotransmitters) and serotonin (neuromodulator) make adolescents more emotional and more responsive to rewards and stress. They become more emotionally vulnerable. 
Serotonin is a chemical messenger that’s believed to act as a mood stabilizer. People who have depression often have low serotonin level. Serotonin levels can affect mood and behavior.
Serotonin is synthesized from the amino acid tryptophan. Teens should eat a generous amount of food that contains tryptophan. These include eggs, cheese, fruits, tofu, fish, nuts, and seeds. Parents can also give protein food supplements that contain FGF that help lower cortisol and trigger serotonin. A good amount of serotonin will help your teens focus more on studies, better emotional well-being and sleep better. 
What we can learn from these scientific data
|They begin to be conscious of how they look.||Verbal compliment of their looks and what they do.|
|Heightened sexual desire and emotions.||Encourage more sports.|
|Increased desire for adventure.||Spend on family vacation.|
|Increased brain capacity to understand and reason.||Allow them to experience consequences.|
|Increased desire for adventure||Spend on family recreation and their interest.|
|Emotional vulnerability and rebellion||Stop talking when they get stressed, provide a healthy diet, and pray more.|
As Christian parents
Although teenagers can better process emotions, they will have difficulty in submission because of conflicting wants and needs. Their desire for more freedom causes them to have a rebellious attitude towards parents and authority.
In Christian parenting, demonic influences usually encourage teenage rebellion. These can elevate to demonic power-struggles. Thus, their spiritual well-being should carefully be guarded.
What Christian parents can do
1. Encourage them to do their quiet time at bedtime.
2. Pray with your teens daily, declaring victory in Christ.
3. Anoint them with oil while speaking life!
4. Fast for them at least once a month.
5. Encourage them to join Youth Fellowships and retreat.
 Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2782527/