Attention deficit-hyperactivity disorder (ADHD) is a well defined condition in child, adolescent and adult psychiatry. Heritability¹ is about 60-90%. It has similar status as a disorder as schizophrenia, bipolar disorder, etc. There are effective psychological and medical treatments which have now been shown to have good long-term outcomes. However, it is massively underdiagnosed in adult psychiatry and forensic psychiatry. 

Definition

The clinical symptoms include problems in relation to inattention and distractibility. Persons with these conditions show poor concentration; are unable to complete reading and other cognitive tasks; shift activities frequently; day dream a great deal; are easily distracted by external stimuli and events; are distracted by internal thoughts; are forgetful; have problems organising time; and pay poor attention to detail. In addition they show some impulsivity symptoms in terms of acting without thinking, talking out of turn, having impulsive urges and temper tantrums. Hyperactive symptoms can include a sense of restlessness, having motor hyperactivity, having difficulty remaining seated during meetings and meals and having difficulty working quietly. 

Children, in terms of hyperactivity, show symptoms of squirming and fidgeting in their seat, running or climbing excessively, not being able to play or work quietly, always seeming on the go. Similar symptoms in adults are manifested by feelings of inner restlessness, feeling overwhelmed, talking excessively. 

Problems with diagnosis^2,3

Some mental health professionals may be resistant to the diagnosis and regard it as a ‘new-fangled American idea’. Lack of training certainly has been a major problem in the past. Fears about stimulants have also played a role. The lack of diagnostic clarity with other conditions is also a problem and there is a very high rate of comorbidity. The depression, anxiety, personality disorder, conduct problems or substance misuse may be diagnosed but the underlying ADHD is missed or not looked for.

Missed diagnosis of ADHD

ADHD is probably the most commonly missed diagnosis in adult and forensic psychiatry. It is often misdiagnosed as mild bipolar disorder. The general moodiness of ADHD leads to this misdiagnosis. Bipolar disorder tends to show elevated mood, increased sexual interest, pressurised speech and racing thoughts while ADHD shows features of excessive talk, impulsive behaviour, sexual promiscuity, etc. The mood swings are far more severe in bipolar disorder. There are increased rates of ADHD in persons with forensic problems. Indeed the first published study on ADHD in prisons was conducted in Ireland by Curran and Fitzgerald.⁴ All forensic patients should have an assessment for ADHD. The treatment of forensic patients in the future is much more hopeful now with the diagnosis and treatment of ADHD and will become very much part of modern forensic psychiatry which will lead to getting away from the nihilism of the past. There is some evidence that a family history of ADHD and bipolar disorder leads to offspring with ADHD and bipolar disorder. ADHD generally has an earlier age of onset than bipolar disorder. Unfortunately in the US the term ‘childhood bipolar disorder’ is often used when ADHD would be the more appropriate diagnosis. This error is now being slowly corrected. 

Another area where ADHD will be central is in substance misuse, where treatment of the underlying ADHD that many patients with substance abuse have will probably lead to better and more hopeful outcomes. The diagnosis and treatment of ADHD will also play a role, hopefully, in the reduction of suicidal behaviour. ADHD is not an uncommon part of marital problems and breakdown. There is a link also in the genetic area between child and adult psychiatric disorders. Developmental thinking is becoming part of adult and child psychiatry with ADHD, autism spectrum disorders, intellectual disability, schizophrenia and bipolar disorder. 

Psychological treatments for ADHD include psychoeducation, counselling, CBT and other behaviour treatments. Combined treatments are often used. 

Training

There are far greater similarities between adult and child psychiatry now than realised in the past. It is critical that developing the ‘ADHD gestalt’ is central to adult psychiatry as well as to child psychiatry and indeed forensic psychiatry. ADHD is a central condition in psychiatry, one of the big neurodevelopmental disorders. A neurodevelopmental perspective is becoming critical to all psychiatry.  

Medication in ADHD

Non-stimulant medications⁵

Atomoxetine (Strattera) is a selective norepinephrine reuptake inhibitor. It is currently licensed up to the age of 18 but in adolescents whose symptoms persist into adulthood and who have shown clear benefit from treatment, it may be appropriate to continue treatment into adulthood. It gives 24-hour cover, which is very important if a person is driving a car at 2.00am in the morning when cover is required. The 24-hour cover also means that the delay which occurs with stimulants in the morning does not occur. Most common side-effects in adults may include constipation, dry mouth, decreased appetite, menstrual cramps, problems passing urine and sexual side-effects. It can slightly increase the risk of suicidal thoughts, with four out of every 1,000 patients developing these. It is not to be used with severe cardiovascular or cerebrovascular disease as it can increase blood pressure and heart rate. It is available as 10mg, 18mg, 25mg, 40mg, 60mg, 80mg and 100mg capsules. Up to 70kg body weight, atomoxetine should be initiated at approximately 0.5mg/kg/day. Maintenance: 1.2mg/kg/day. Over 70kg maintenance: 80mg, maximum 100mg.  

The NICE guidelines⁶ point out that atomoxetine may be increased to 1.8mg/kg/day up to a maximum of 120mg/day.

Stimulant medications

Methylphenidate (Ritalin) was first synthesised in 1944. It was initially marketed in 1957 for chronic fatigue and depression. Methylphenidate blocks the transporter for the reuptake of dopamine. It improves frontal lobe functioning. Doses range from 5mg to 40mg. The NICE guidelines point out that methylphenidate can be increased to 0.7mg/kg per dose up to three times a day or a total dose of 2.1mg/kg/day (up to a maximum of 90mg/day for immediate release or an equivalent dose of modified-release methylphenidate). Tolerance in ADHD in normal doses does not appear to be a problem. Stimulants have an efficacy of about 70% in reducing the symptoms of ADHD, improving cognition, improving self-esteem, and improving social and family function. In terms of short-acting stimulants methylphenidate has a duration of action of between two and four hours; dexamphetamine between four and five hours. Then there are the long-acting stimulants. 

Long-acting stimulants

There are several newer long-acting forms of methylphenidate. Equasym XL and Medikinet MR last about six to eight hours. Concerta XL lasts about eight to 12 hours. In terms of stimulant equivalents, short-acting methylphenidate of 15mg is equivalent to Concerta XL of 18mg; 30mg of short-acting methylphenidate is equivalent to 36mg of Concerta XL, 30mg of Equasym XL and 30mg of Medikinet MR.

Equasym XL has 10mg, 20mg and 30mg capsules available. 60mg is the maximum per day for children. For children with problems swallowing it can be sprinkled on soft food followed by drink. It is a long-acting form of methylphenidate.

Medikinet MR comes in 5mg, 10mg, 20mg, 30mg and 40mg capsules. There are also non-MR Medikinet tablets of 5mg, 10mg or 20mg.

Ritalin and Ritalin LA are not applicable to adults, according to the manufacturer. It has 10mg tablets, short acting. Maximum is 40mg per day. Long-acting Ritalin has 20mg, 30mg and 40mg capsules. 

Pre-drug assessment

Pre-drug assessments of methylphenidate or atomoxetine include psychiatric assessment and questions about fainting, undue breathlessness and other cardiovascular symptoms. Heart rate and blood pressure must be checked, as well as weight. For children this will include height. Any family history of cardiac disease should be documented and an electrocardiogram carried out if there is a medical or family history or death from cardiovascular disease before the age of 30.  

Common side-effects may include reduced appetite, palpitations, mood changes, headaches, feeling nervous and not being able to sleep. Uncommon side-effects at less than 1/1000 suicidal thoughts, hallucinations, tics, mania (0.1%).

References

1. Kirley A, Daly G, Hawi Z, Fitzgerald M, Gill M. Dopaminergic system genes in ADHD: towards a biological hypothesis. Neuropsychopharmacology 2002; 27: 607, 619 
2. Fitzgerald M, Belgrove M, Gill M. Handbook of Attention Deficit Hyper Activity Disorder. Wiley: Chichester, 2007 
3. Fitzgerald M. Does adult ADHD exist? J Psychiatry Neurosci 2001; 2(1): 114-116 
4. Curran S, Fitzgerald M. Attention deficit hyperactivity disorder in the prison population. Am J Psychiatry 1999; 156(10): 1664-1665 
5. Fitzgerald M. Psychopharmacological treatment of adolescent and adult ADHD. Ir J Psychol Med 2001; 18(3): 93-98 
6. National Clinical Practice Guideline No 72: ADHD. British Psychological Society/Royal College of Psychiatrists: London, 2009