Significant mental health problems can and do occur in young children. Children can show clear characteristics of anxiety disorders, attention-deficit/hyperactivity disorder, conduct disorder, depression, post-traumatic stress disorder, and neurodevelopmental disabilities, such as autism, at a very early age. That said, young children respond to and process emotional experiences and traumatic events in ways that are very different from adults and older children. Consequently, diagnosis in early childhood can be much more difficult than it is in adults.