(HealthDay News) -- Determining if a child's troubling behavior is "part of growing up" or a sign of a mental health problem can be difficult.
Parents should contact a mental health professional if symptoms last weeks or more and interfere with the child's daily life, says the National Institute of Mental Health.
Warning signs of a mental illness may include:
Minimal interest in things that the person once enjoyed.
Too much or too little sleep.
Smoking, drinking or drug use.
Excessive exercise or diet.
Thoughts of suicide.
Risky or destructive behavior.