Knowing about marijuana can help you tell if your child or someone else is using it, and help them get treatment.

Marijuana is the most commonly used mind-altering drug in the U.S., after alcohol. It's illegal in some states, but other states have legalized it for medical and recreational use. The drug comes from the hemp plant. The chemicals in marijuana are found in the leaves and flowering shoots. THC is the most well-known of these chemicals. There are also manmade chemicals that act like THC. But they are much stronger. They are synthetic marijuana. They are sold under names, such as K2, Kronic, or Spice.

Marijuana can be used in several forms. It's often smoked as a dry, shredded green and brown mix of flowers, stems, seeds, and leave. It can be smoked as a cigarette (joint), in a pipe or bong, or as a blunt. A blunt is a cigar casing that has been filled with marijuana. Vape cartridges and pens filled with marijuana also have become quite popular.

The drug might also be mixed in food or brewed as a tea. There is a large commercial market for "edibles." This term refers to marijuana mixed in products meant to be eaten.

A more concentrated form called hashish is made from the tops of female plants. It has the highest concentration of THC. It's often pressed into small, solid pieces that look like a small piece of chocolate. These are often put inside a regular cigarette and smoked.

Studies suggest that some types of marijuana are now much stronger than in the past.

Users can become dependent on or addicted to marijuana, just as someone can with alcohol and tobacco. A person is dependent on marijuana when they have withdrawal symptoms. Someone is addicted to the drug when the drug use interferes with many aspects of life but they still can't stop using it. Drug use may affect their finances, schoolwork, and social life.

These are some effects of marijuana use:

• Feeling of joy, relaxation
• Increased sense of sight, hearing, and taste
• Increased appetite
• Loss of coordination. This makes it difficult, even dangerous, to do things such as drive a car.
• False sense of time
• Trouble thinking and problem-solving that can also affect driving
• Can't tell the difference between oneself and others
• Anxiety or panic reactions or being overly suspicious and distrustful can be seen with higher concentrations. This doesn't always happen. In fact, many people take marijuana to treat anxiety.

Signs of marijuana use include:

• Being dizzy
• Having trouble walking
• Being silly and giggly for no reason
• Having red, bloodshot eyes
• Having a hard time remembering things that just happened

When the early effects fade after a few hours, the user can get very sleepy.

Some long-term marijuana users who smoke the drug daily may have repeated and uncontrolled vomiting (cannabinoid hyperemesis syndrome). They often feel better when they take a hot shower. But many people get medical care.

If you're worried that your child may be using marijuana, know what signs to look for. These include the following behaviors:

• Withdrawal or separation from others
• Depression
• Excessive tiredness
• Not careful about personal hygiene or grooming
• Hostility
• Relationships with family members and friends get worse

Other things that may be linked to drug use include changes in school performance, skipping or missing school, lost interest in sports or other favorite activities, and changes in eating or sleeping habits.

Parents should also be aware of signs of drugs and drug items. These include:

• Pipes and rolling papers
• Strange smell on clothes and in the bedroom
• Using incense and other deodorizers
• Using eye drops
• Frequent red eyes
• Unexplained changes in appetite
• Eating more food

Long-term studies of high school students show few young people use other drugs without first trying marijuana. So the chance that a child will try cocaine is much higher if they have tried marijuana.

Marijuana can be harmful in several ways. Some of these are felt right away. Others damage a person's health over time. Marijuana affects short-term memory and the ability to handle difficult tasks. When using stronger types of marijuana, even simple tasks can be difficult.

The drug affects a person's ability to understand and also their reaction time. So users get in car crashes more often than people who don't use marijuana. They also may have more risky sexual behavior. There is a strong link between drug use, unsafe sex, and the spread of sexually transmitted infections.

Students who use marijuana may find it hard to study and learn because it hurts the ability to focus and pay attention. And young athletes may perform poorly. THC affects timing, movements, and coordination.

Synthetic marijuana products can have even more harmful effects. Hallucinations, kidney damage, seizures, and even death have been reported with these products.

Marijuana smoke contains some of the same compounds that cause cancer as tobacco. But they are sometimes in higher concentrations.

Treatments for marijuana dependence are similar to therapies for other drug-abuse problems. These include detoxification, behavioral therapies, and regular attendance at support-group meetings, such as those sponsored by Narcotics Anonymous.

Recent news stories and state laws have addressed the possible medical benefits of marijuana and its casual or recreational use. But these don't apply to children and teens. Teens often refer to these stories and laws to defend their use of marijuana.

There are many reports of small children overdosing on marijuana by accidentally eating edibles. These edibles often take the form of a gummy candy. Children eat them thinking they are candy.

There's no quick and easy way to prevent teen drug use. But you can influence your children by setting clear rules about not using drugs. Talk with your children about the dangers of using marijuana and other drugs. Act as role models, and stay very involved in your children's lives.