ADHD is a clinical condition characterised by lack of attention, excessive activity and impulsive behaviour. Broadly classified by the Diagnostics and Statistics Manual of Mental Disorders (DSM-IV), ADHD consists of 3 main types –
ADHD, Predominantly Hyperactive-Impulsive type
In this type, patients demonstrate a primarily hyperactive and impulsive picture, but only a few inattention symptoms. Predominant symptoms include constant interrupting, fidgety behaviour, and standing up often when requested to sit down, running around against request and being noisy when playing about. In addition, they may also constantly interrupt others and may even invade their personal space. Inattentive symptoms such as not listening to instructions, not paying attention and being constantly distracted are present, but are not the main feature.
ADHD, Predominantly Inattentive type
Here, the patient demonstrates symptoms of inattentiveness such as lack of attention to detail, not following clear instruction, being constantly distracted, not listening when spoken to and being careless. Daily activity routines may be forgotten. Hyperactivity symptoms as described previously are a few.
ADHD, Combined type
Here, the patient demonstrates the symptoms of both the above described types.
While this classification is fairly broad, other methods of classification have emerged, such as the one described by Dr. Daniel Amen, a consultant psychiatrist. Based on a set of hallmark symptoms and appearance of the brain on a special scan called a SPECT scan, ADHD has been divided into 7 types.
Type 1 - Classic ADHD
In this type, the patient demonstrates the classic symptoms of ADHD such as shortened attention span, easy distractibility and poor organisation skills. In addition, the previously described symptoms of hyperactivity and impulsive behaviour also exist. Patients respond well the stimulant drugs.
Type 2 - Inattentive ADHD
Here, the patient exhibits features of the inattentive type of ADHD described previously, but lack the hyperactivity features. This group also responds well to stimulant drug treatments.
Type 3 - Overfocused ADHD
This specific type of ADHD is where the patient presents with ‘negative behaviours’. This means that they tend to argue, not listen to kind instructions and generally demonstrate an opposing attitude. Treatment includes stimulating drug therapy combined with antidepressants.
Type 4 - Temporal lobe
The temporal lobe is a part of the brain that lies on the sides. Patients with this form of ADHD tend to demonstrate irritability, poor memory and difficulty learning along with aggressive behaviour. The recommended treatment is the use of anti-epileptic drugs (drugs used to treat seizures).
Type 5 - Limbic ADHD
In this type, patients also exhibit symptoms suggestive of underlying depression. Treatment must include antidepressant medications.
Type 6 - The Ring Of Fire
Here, the patients demonstrate extremely moody behaviour, over-activity and opposing behaviour, to name a few features. Using stimulant treatment can worsen this condition, and is avoided.
Type 7 - Anxious ADHD
Patients with anxious ADHD demonstrate distractive behaviour, anxiety, nervous disposition, being uncomfortable in social situations and physical symptoms such as abdominal symptoms and headaches.
The above are the different ways ADHD is classified. Treatments depend on the type as do the long term outcomes.