As you navigate the adolescent years with your child, you might wonder about his or her behavior at times. Is it normal teenage moodiness, with all of the ups and downs that are common during this time of life? Or is your teen’s behavior and attitude indicative of a potential mental health problem? It can be difficult to know for sure, so if you do have concerns about your child’s mental health and they display mental illness warning signs, always consult his or her primary care doctor or a counselor. Here are 7 mental illness warning signs to look out for that will clue you in that a mental health evaluation by a professional is in order.

#1. Changes in Eating Habits

Your teen might eat everything not nailed down for a few weeks before a growth spurt, then settle into a three-meal-per-day habit for a while. Some teens routinely skip breakfast, then fill up on fruit, chips or candy later in the day. While not all of these are healthy patterns, they’re common, and they don’t necessarily mean that your teen has a problem.

If your teen is not eating much at all anymore, however, or seems obsessed with food, nutrition or dieting, that could be a red flag. Drastic overeating and binging, with or without purging, is also a potential issue. If your teen’s eating habits have changed significantly or you notice them gaining or losing a lot of weight, particularly if it happens over a relatively short period of time, a medical checkup is in order.

#2. Changes in Sleep Patterns

Again, teens’ sleep habits can run the gamut. Your teen might love to stay up into the wee hours of the night on the weekends, and then sleep until mid-afternoon. Adolescents go through changes in their circadian rhythm, so this can be normal.

A teen who is suddenly getting by on far less sleep than usual, however, could be throwing up a red flag. So can a teen who is needing to sleep excessively. Most teens need about nine hours of sleep per night. If your teen is averaging many hours more or less than this, there could be a physical condition, a mental health issue, or a drug problem involved.

#3. Dramatic Decline in Grades

Not all teens are straight-A students (in fact, most aren’t!), but you know your child’s baseline. If grades are plummeting, there’s got to be a reason why. Sometimes that reason could be a mental health disorder or a drug or alcohol problem. If it’s just one or two classes, talk to your child’s teacher or guidance counselor about the issue. If your teen is suddenly failing several classes, however, it’s definitely worth checking into the situation to see what’s going on.

#4. Secrecy and Isolation

It’s normal for teens to want to spend time alone in their bedrooms or going for solitary walks. However, this should be balanced with time spent with friends and family. If your teen is spending most of his or her time alone, this could indicate depression, an addiction, social anxiety, or some other type of treatable mental health condition.

Similarly, many teens want a lot of privacy. Secrecy, however, is a different story. Some teens will go to great lengths to hide self-mutilation, substance abuse, and other serious issues. Try to keep communicating with your teen so you can understand what’s going on in his or her life. If your teen doesn’t want to talk to you, arrange for them to spend some time with another trusted adult or a counselor. It’s important for teens to share their thoughts and feelings with someone.

#5. Extreme Anger or Sadness

All of us go through difficult emotions, and it might seem like your teen goes through them more often than you do. Between hormonal changes and the stresses of growing up, adolescents do cycle through good and bad moods frequently.

If your teen is extremely weepy and sad or angry and destructive for no discernible reason, however, this could be a sign of a mental health issue, particularly if it lasts longer than a few hours. Also keep your eye out for extreme elation and giddiness, especially if it tends to come after a time of very negative feelings. While some mood swings can be normal, if you think that your teen’s are abnormal, it’s best to get it checked out.

#6. Sudden Changes in Social Life and Activities

Most teens have a core group of good friends and at least one or two activities that they enjoy. Sometimes friends will come and go, but if your teen suddenly drops a lot of his or her friends, this could indicate a mental health issue. Keep an eye and ear out to see if your child is picking fights, completely ignoring people, or simply not being able to make friends at all. If any of these are happening, it’s worth looking into.

Similarly, if your teen drops a favored activity for something else, it can be normal and healthy. If he or she drops all activities, there might be a reason why. Sometimes kids are anxious or depressed, and this causes them to want to simply stay home. Other times, an addiction or other unhealthy behavior can be taking up their time. Investigate and find out what is going on.

#7. Your Teen Thinks There’s Something Wrong

If you have a teen who talks to you openly and he or she expresses concern that there’s a problem, take it seriously. Your child might not know exactly how to verbalize what they’re feeling, but if you hear things like, “I feel like I’m not myself,” or “I just feel sad all the time,” this warrants a visit to the doctor or counselor. Many teens are introspective and will have insight on their mental health issues before they give enough outward mental illness warning signs for you to notice, so if your teen speaks up, treat it as a red flag. Trust your child to know him- or herself well enough to know when something is wrong.

There are no instructions that come with teenagers, and it can feel overwhelming to you to be vigilant for mental illness warning signs. In general, if your teen seems happy and well-adjusted most of the time, they likely are. However, if you notice any of the mental illness warning signs mentioned above or that small voice tells you that something seems wrong, don’t be afraid to act on it. Bringing your child to the doctor when you are worried can ease your mind if all seems normal, but more importantly, it can catch the early signs of a potentially serious mental health disorder before it gets worse.