ADHD is associated with abnormally low levels of the neurotransmitters (brain "messengers") that send information between two parts of the brain associated with pleasure/reward, mood and complex behaviors, the prefrontal cortical area and the basal ganglia (i.e. dopamine and noradrenaline). 

While some behaviors associated with ADHD are "normal" and not a cause for concern to most people, someone with ADHD will have trouble controlling these behaviors and will show them persistently for an extended period of time.

Signs of inattention include:

• Becoming easily distracted, and jumping from activity to activity
• Quickly becoming bored with a task
• Difficulty focusing attention or completing a single task or activity
• Trouble completing or turning in homework assignments
• Losing things such as school supplies or toys
• Not listening or paying attention when spoken to
• Daydreaming or wandering with lack of motivation
• Difficulty processing information quickly
• Struggling to follow directions

Signs of hyperactivity include:

• Fidgeting and squirming, having trouble sitting still
• Non-stop talking
• Touching or playing with everything
• Difficulty doing quiet tasks or activities

Signs of impulsivity include:

• Impatience.
• Acting without regard for consequences, blurting things out.
• Difficulty taking turns, waiting or sharing. Interrupting others.

My preschooler is too young to have ADHD

ADHD symptoms can appear as early as the preschool years.

They're just lazy and unmotivated

A child who finds it nearly impossible to stay focused in class, or to complete a lengthy task such as writing a long essay, may try to save face by acting as though he is too lazy to finish. This behavior may look on the outside like laziness or lack of motivation, but in reality it stems from a considerable difficulty in functioning.

ADHD is managed and treated in several ways:

• Medications, including stimulants, nonstimulants and antidepressants
• Behavioral therapy
• Self-management, education programs and assistance through schools or work or alternative treatment approaches