DHD (Attention Deficit Hyperactivity Disorder) is a neurological disorder characterized by a combination of symptoms such as attention problems, hyperactivity and impulsivity. The symptoms of ADHD can vary from person to person and can manifest in different ways. Below are some common traits of ADHD:

1. Attention problems: People with ADHD often have trouble focusing their attention on one task and holding it for long periods of time. They can be easily distracted by external stimuli or internal thoughts and may have difficulty concentrating.
2. Hyperactivity: People with ADHD are often hyperactive and have difficulty sitting still or relaxing. They can move a lot and be restless, and often tend to act impulsively without thinking about the consequences.
3. Impulsivity: People with ADHD often have difficulty controlling their impulses and can act impulsively without thinking about the consequences. They can get bored easily and look for new and challenging experiences, which can lead to risky behavior.
4. Problems with organization and planning: People with ADHD often have difficulty organizing their time and scheduling tasks. They may also have difficulty starting or completing tasks. Especially visible when tasks are too complex or too boring.
5. Emotional instability: People with ADHD may have difficulty controlling their emotions and may quickly become angry, frustrated, or irritable.

Some people with ADHD regulate emotions by moving or by chewing on pencils, pens or hair. Moving (or fidgeting) and chewing helps to relax, as well as to exclude stimuli and focus on a task. A chewing chain can certainly offer a solution for the need for chewing.