Article in English: Think about why you are concerned about your child. Do they seem to be feeling differently? Have they had unexplained changes in mood? Maybe it seems like your child is acting fearful for no clear reason. It is possible that it could be marijuana use. Marijuana is a psychoactive substance; it interacts with the user's brain, temporarily changing the way he or she thinks and feels. Smoking marijuana can cause cognitive impairment during a high which increases as more marijuana is consumed. If you think your child may be high, look for the following mental symptoms:  Slowed reaction time Impaired decision-making Diminished memory A tendency to "space out" or lose the thread of conversations Paranoia or irrational beliefs that one is in danger. This symptom may be more common among users with existing psychiatric problems or a predisposition to them. It's normal to be concerned about your teenager, but it is also normal for teens to go through rapid mood changes. At times, trying to keep track of your child's moods can seem like you are on a roller coaster. It is important to remember that teenagers are going through a lot of changes, both physically and emotionally. Some changes in behavior and mood are typical. Try doing some research or asking a trusted friend for advice in order to help you better understand your teen's actions. Even though your teen might not always acknowledge it, you are one of the most important people in his life. Your relationship is sometimes a big factor in why your teen behaves the way he does. Try to step back and objectively think about your relationship. Has anything changed recently? Is it possible that your teen is acting differently as a reaction to something that is going on in your home life? Although teens often behave in a confusing manner, not all of it can be chalked up to normal teenage angst. Pay close attention to all aspects of your child's life, while at the same time respecting their boundaries and growing independence. If the signs are all pointing to possible...

Summary in Vietnamese:
Xem xét tâm trạng của trẻ. Quan sát các thay đổi trong hành vi. Hiểu về bộ não của trẻ vị thành niên. Đánh giá quan hệ giữa bạn và con bạn. Biết khi nào đáng lo ngại.