Adult ADHD (Attention Deficit Hyperactivity Disorder)

The exact cause is unknown but the condition has been shown to run in families. Research has also identified a number of possible differences in the brains of people with ADHD when compared with those without the condition.

Other potential factors include:

• being born prematurely (before the 37th week of pregnancy)
• having a low birthweight
• smoking, or alcohol or drug abuse during pregnancy.

ADHD can occur in people of any intellectual ability, although it’s more common in people with learning difficulties.

Diagnosing Adult ADHD is more difficult because there’s some disagreement about whether the list of symptoms used to diagnose children and teenagers also applies to adults. In some cases, an adult may be diagnosed with ADHD if they have 6 or more of the symptoms of inattentiveness, or 6 or more of hyperactivity and impulsiveness, listed in diagnostic criteria for children with ADHD.

As part of your assessment, the Adult ADHD specialist will ask about your present symptoms. However, under current diagnostic guidelines, a diagnosis of ADHD in adults cannot be confirmed unless your symptoms have been present from childhood.

If you find it difficult to remember whether you had problems as a child, or you were not diagnosed with ADHD when you were younger, your specialist may wish to see your old school reports or talk to your parents, teachers or anyone else who knew you well when you were a child.

For a diagnosis of Adult ADHD to be made, symptoms should also have a moderate effect on different areas of their life, such as:

• underachieving at work or in education
• driving dangerously
• difficulty making or keeping friends
• difficulty in relationships with partners.

If your problems are recent and did not occur regularly in the past, you’re not considered to have ADHD as it’s currently thought that ADHD cannot develop for the first time in adults.

Treatment for ADHD can help relieve the symptoms and make the condition much less of a daily problem.

​ADHD can be treated using medication or therapy but a combination of both is often best. Treatment is usually arranged by a specialist, such as a psychiatrist, although the condition may be monitored by your GP.

There are 5 types of medication licensed for the treatment of ADHD:

• Methylphenidate
• Dexamfetamine
• Lisdexamfetamine
• Atomoxetine
• Guanfacine

​These medications are not a permanent cure for ADHD but may help someone with the condition concentrate better, be less impulsive, feel calmer, and learn and practise new skills.

​If you’re prescribed one of these medications, you’ll be given small doses at first, which may then be gradually increased (titration). You will need to see your Adult ADHD specialist and GP for regular check-ups to ensure the treatment is working effectively and check for any side effects or problems. It’s important to let your GP know about any side effects and talk to them if you feel you need to stop or change treatment. Your specialist will discuss how long you should take your treatment but, in many cases, treatment is continued for as long as it is helping.

Methylphenidate is the most commonly used medication for ADHD. It belongs to a group of medicines called stimulants, which work by increasing activity in the brain, particularly in areas that play a part in controlling attention and behaviour.

​The medication can be taken as either immediate-release tablets (small doses taken 2 to 3 times a day) or as modified-release tablets (taken once a day in the morning, with the dose released throughout the day).

​Common side effects of methylphenidate include:

• a small increase in blood pressure and heart rate
• loss of appetite, which can lead to weight loss or poor weight gain
• insomnia
• headaches
• stomach aches
• mood swings

Lisdexamfetamine is a similar medication to dexamfetamine and works in the same way. Adults may be offered lisdexamfetamine as the first-choice medication instead of methylphenidate.

Lisdexamfetamine comes in capsule form, taken once a day.

Common side effects of lisdexamfetamine include:

• decreased appetite, which can lead to weight loss or poor weight gain
• aggression
• drowsiness
• dizziness
• headaches
• diarrhoea
• nausea and vomiting

Dexamfetamine is similar to lisdexamfetamine and works in the same way.

​Dexamfetamine is usually taken as a tablet once or twice a day, although an oral solution is also available.

Common side effects of dexamfetamine include:

• decreased appetite
• mood swings
• agitation and aggression
• dizziness
• headaches
• diarrhoea
• nausea and vomiting

Atomoxetine works differently from other ADHD medications. It’s a selective noradrenaline reuptake inhibitor (SNRI), which means it increases the amount of a chemical in the brain called noradrenaline. This chemical passes messages between brain cells, and increasing it can aid concentration and help control impulses.

Atomoxetine may be offered to adults if it’s not possible to use methylphenidate or lisdexamfetamine.

​Atomoxetine comes in capsule form, usually taken once or twice a day.

Common side effects of atomoxetine include:

• a small increase in blood pressure and heart rate
• nausea and vomiting
• stomach aches
• trouble sleeping
• dizziness
• headaches
• irritability

​Atomoxetine has also been linked to some more serious side effects that are important to look out for, including suicidal thoughts and liver damage. If either you begin to feel depressed or suicidal while taking this medication, speak to your doctor.

Guanfacine acts on part of the brain to improve attention, and it also reduces blood pressure.

It may be offered to teenagers and children over the age of 5 if it’s not possible to use methylphenidate or lisdexamfetamine. Guanfacine should not be offered to adults with ADHD.

Guanfacine is usually taken as a tablet once a day, in the morning or evening.

Common side effects include:

• tiredness or fatigue
• headache
• abdominal pain
• dry mouth