Types of ADHD

In some people the signs of attention-deficit/hyperactivity disorder ( ADHD) seem obvious - fidgeting constantly, having difficulty paying attention in school or at work, and leaving every task unfinished. Based on these and other symptoms, doctors have designated different types of ADHD, which are used to diagnose ADHD and prescribe treatment (often stimulant medications, such as Methylphenidate).

The symptoms of ADHD may mimic those of other conditions, and sometimes the signs are subtler and harder to distinguish.

How is ADHD usually diagnosed?

Most psychologists, psychiatrists and paediatricians diagnose ADHD based on a series of inattention and hyperactivity symptoms. For someone to be diagnosed with ADHD, the behaviours must have lasted for at least six months, and they must be severe enough to disrupt school and other aspects of the individual's life.

Inattention symptoms include:

• Not paying attention to detail
• Making careless mistakes
• Failing to pay attention and keep on task
• Not listening
• Being unable to follow or understand instructions
• Avoiding tasks that involve effort
• Being distracted or forgetful
• Losing things that are needed to complete tasks

Hyperactivity-impulsivity symptoms include:

• Fidgeting
• Squirming
• Getting up often when seated
• Running or climbing at inappropriate times
• Having trouble playing quietly
• Talking excessively or out of turn
• Interrupting

Based on these criteria, three subtypes of ADHD have been identified:

1. ADHD, combined type. Both inattention and hyperactivity-impulsivity symptoms.
2. ADHD, predominantly inattentive type. Inattention but not hyperactivity-impulsivity symptoms.
3. ADHD, predominantly hyperactive-impulsive type. Hyperactivity-impulsivity but not inattention symptoms.