Attention deficit hyperactivity disorder across the lifespan

This article is a research summary of published and non-published work pertaining to Attention Deficit Hyperactivity Disorders (ADHD). ADHD is one of the most common child mental health disorders and is under-recognised in children (5.29%} and adults (2.5%}. ADHD is highly heritable with a multifactorial pattern of inheritance. Siblings and parents of a child with ADHD are 4 to 5 times more likely to have

ADHD. Methylphenidate is the first line pharmacological treatment with a combined response (this includes trials of other licensed amphetamines) rate of 95%. All clinicians working in mental health should be aware of this disorder, comfortable diagnosing and treating people with ADHD. Young people with untreated ADHD are 5 times more likely to develop antisocial behaviour, substance abuse and other co morbid psychiatric disorders.

Introduction

The purpose of the review is to cover the epidemiology, aetiology, diagnostic criteria and different managements of Attention Deficit Hyperactivity Disorder (ADH D) with specific reference to practice of ADHD assessment and treatment management in Malta. This review’s target audience is for all clinicians to better understand what ADHD is and explain any misconceptions there are related to the medications which are used to manage ADHD and relate this to Malta. The authors will look to answer the questions using evidence based published and unpublished research.

What is ADHD?

ADHD is among the most common neurobehavioral disorders presenting in children and adolescents. It is characterised by persistent symptoms of inattention, hyperactivity and impulsivity according to Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM 5) present in

two of three environments (namely home, school, clinic). The onset of the symptoms must have been present before the age of 12 years; this was increased from the previous DSM- IV due to the recognition that adults may also be diagnosed with ADHD, however may not clearly remember their symptomatology in early childhood.2 This increase in age to diagnosis was thought to create a sudden rise in the prevalence of ADHD diagnosis around the world. ADHD is also classed under the term Hyperkinetic Disorder in the International Classification of Diseases 10th edition (ICD10) with similar characteristics including early onset, disorganized, ill-regulated, excessive activity, recklessness and impulsivity. The main difference between the DSM-5 and ICD- 10 diagnostic criteria is that in the former a young person (YP) may be diagnosed with concentration difficulties only, also known as Attention Deficit Disorder (ADD) or hyperactivity and impulsive symptoms but no concentration difficulties or ADHD combined type (attention, hyperactivity and impulsive symptoms). As opposed to the ICD-10 diagnostic criteria where a diagnosis is made only when all three core symptoms are present.

Over the last decade there has been interest in the pragmatic use of social language in children with ADHD, this is the domain that manages conversational contexts. It was reported that as many as 50% of children with ADHD have less developed pragmatic language skills (receptive and expressive) related to their typically developing peers. They also suffer from a developmental delay in onset of talking. As a result, social problems are reported in 52-82% of children with ADHD; such as having fewer reciprocated friendships, and being more often disliked by their peers. Social problems arise due to symptoms of impulsivity (e.g. interrupting, difficulty waiting their turn), and inattention (e.g. not listening). This means that a child with ADHD has a greater chance of getting into trouble at school and then when called in to explain to the teacher what really happened, struggles to verbalise the experience, as a result may be judged as defiant. Subsequently peer rejection and education failure has been associated with negative long-term outcomes such as substance abuse, delinquency and academic problems.

Is ADHD a valid diagnosis in adults?

ADHD is a common behavioural disorder that is associated with significant adult psychopathology, social and academic impairments and the risk for negative long­ term outcomes. There is no doubt that in many cases ADHD symptoms persist into adult life and cause significant clinical impairments. ADHD diagnosed in childhood tracks on through to adulthood, with 4-15% of adults retaining the full diagnosis and 50-66% of YP presenting in partial remission of ADHD symptoms. The main clinical issue is recognition of the disorder in adults and quantifying the impact on adult mental health.

To date there has been considerable debate on whether ADHD is a disorder solely present in YP or whether there is evidence that ADHD symptoms persist through to adult life. The latter hypothesis, is strongly supported by research, which found that symptoms of ADHD persist in 65% of adults. Furthermore, it is thought that the ADHD symptoms do not resolve in adulthood, but rather adults develop the required social skills to control and mask their ADHD symptoms and adapt to social requirements. On the other hand, Moncrieff has argued that the validity of symptoms in adults do not automatically follow those used to diagnose children and concluded that the rapid growth in interest in adult ADHD could be the result of the drug companies seizing the opportunity to expand on a lucrative market.

Clinical presentation in adults

Adults with ADHD clinically present with more symptoms of poor attention (rather than hyperactivity) and ceaseless mental activity (distracted mind) such as procrastinating to start a job, then trying to multitask and carry out a number of jobs at the same, without ever finishing any of these jobs or finishing them with careless mistakes. Hyperactivity (over activity) is not as prominent symptom in adults, since adults learn to manage their behaviour, on the one hand through learning to adapt to social norms and also due to development (maturity) of the pre-frontal cortex. Mood dysregulation and lability are common symptoms in adults with ADHD.

These symptoms lead to low tolerance of frustration, falling out with peers and colleagues, and as a result this effects their self-esteem and can lead to poor performance at the work place.

Epidemiology – how common is ADHD?

The worldwide prevalence of ADHD in children O – 18 years was reported to be 5.29% in a systematic review and meta­ regression analysis conducted by Polanczyk et al,18 with minor differences found between countries around the world. For example in the United Kingdom it was estimated that the prevalence of ADHD is 2.23% of children age 5-15 years.  Whilst in the United States of America, the National Health Interview Survey (NHIS) in 2006 estimated the prevalence of ADHD among children age 3-17 is 7%.20 The possible reasons for the significant difference in prevalence rates between these two countries has been widely debated; the most common reasons for the low prevalence reported in the UK is due to the strict adherence to ICD-102 as opposed to the DSM-5 in the USA. Furthermore, Biederman reported that the USA have higher rates of social deprivation and experiences of trauma as a country when compared to the UK. In addition, one of the reasons apart from the more lax DSM-5 criteria for diagnosing ADHD, is that for parents to get clinician reviews refunded by insurance, a diagnosis needs to be given. It is reported that ADHD is more common in YP living in urban rather than rural communities and there is a link with low socio-economic status. It is believed that ADH D is an under­ identified and under treated disorder.

In adulthood, the overall pooled prevalence rate for adult ADHD was 2.5%22 reported in a robustly conducted meta-analysis. Furthermore, Simon reported that children do not outgrow the disorder (ADHD) but they outgrow the diagnostic criteria (ICD-10, DSM-5),

therefore this means that there may be an underestimation of the true prevalence of this disorder in adults. Some of the reasons for the possible underestimation include: different methodological and diagnostic differences used in the different studies lead to differences in results, symptom recall bias, the use of DSM-5 diagnostic

criteria to diagnose adult ADH D23 which were written for YP, not adults,12 and the overlap of the symptoms of adult ADHD with other disorders, as well as the adult co-morbid disorders.

ADHD is more prevalent in males than females,  however the ratio varies depending on the study design of populations. The reported range varies between 9 males is to 1 female and 2.5 is to 1. Further analysis has gone into why there is such a discrepancy between males and females, it was hypothesised that it is almost socially accepted for boys to be hyperactive (boisterous), however girls are praised for being more obedient. It is also reported that girls tend to daydream more. However, day dreamers tend to still be quiet in class, therefore not picked up by teachers as having a concentration problem which may be effecting their overall academic potential.

Behaviours that reflect executive function impairments in adults

Activation: organising, prioritising and initiating work

Focus: focusing, sustaining and shifting attention to tasks

Effort: regulating alertness, sustaining effort and processing speed

Emotion: managing frustration and regulating emotions

Memory: utilising working memory and accessing recall

Action: monitoring and self-regulating of activities

Non-Stimulants

Atomoxetine increases noradrenaline and may also increase dopamine in the prefrontal cortex. It also blocks noradrenaline re- uptake pumps. Atomoxetine appears to be an efficacious treatment of children and adults with ADHD, and has a half-life of 24 hours so is prescribed as a once daily dose and is not a controlled drug. Its lack of abuse potential may be an advantage.

The effect size is smaller (0.7) than that of the stimulants, 58 however in recent findings published by,59 it was reported that once the

controlling for parental reporting, the effect size of Atomoxetine was only 0.3 (which means a mild effect).

Table 3: Medication efficacy in psychiatry65   Medication Efficacy Numbers Needed to Treat (NNT) Effect Size (range 0-1) Methylphenidate 4 1.0 Amfetamine 4 1.0 Atomoxetine 4 0.7 SSRI for depression in adults 10 0.5 Antipsychotics for Schizophrenia in adults 10 0.25

There are no long-term adverse effects of Atomoxetine, however the notable immediate effects include sedation and fatigue, a decrease in appetite (however this is less than for stimulants), an increase in heart rate of 6 to 9 beats per minute and an increase in blood pressure of 2 to 4 mmHg. Insomnia, anxiety, agitation, irritability, dizziness, nausea and vomiting are reported, however, these generally subside within 2 weeks of starting medication. Rare but potentially life­ threatening side effects include orthostatic hypotension, hypomania, mania, suicidal ideation and very rarely liver failure.

Non-Pharmacological treatment

Non-pharmacological management for ADH D includes behavioural therapy, CBT, family therapy, social skills training, parenting groups, neurofeedback, special diets, avoiding eating food with artificial colouring from ones diet and supplementation with free fatty acids such as omega 3 and 6. This treatment could be used alone or in combination with stimulant medication and must be maintained over an extended period of time for more positive and long lasting results. The results on non-pharmacological studies remain mixed. In the large MTA follow up study there was no difference found between those YP prescribed stimulant medication alone compared to those receiving a combination of medication and psychological treatment. There are some small scale individual studies which demonstrate the benefit of omega 3 and 6 fatty acids, cognitive training, parenting groups and removal of diets containing artificial colouring, however in a large and robust systematic review and meta­ analysis, it was found that only in the case of food colouring was there some evidence to show the benefit on the treatment of ADHD symptoms and all the rest showed no difference when compared to placebo effect.

Conclusion

ADHD is a common neurodevelopmental disorder which is possibly under-recognised in mental health settings and in community both in children (5.29%) and adults (2.5%). ADHD is a highly heritable disorder 0.76 and parents and siblings of a child with ADHD are 4 to 5 times more likely to have ADHD.

ADHD is easy to treat with 95% of correctly diagnosed patients (children or adults) responding to treatment Methylphenidate is suggested as the first line of pharmacological treatments. For most patients with ADHD symptoms, these should be safely managed by the use of a single medication, however there is evidence where methylphenidate immediate release has been added to augment the effect of methylphenidate extended release and also that of Atomoxetine, when the clinical response remains inadequate. There is initial good evidence which suggests that stimulants and alpha-2 agonist combinations may have an additive effect, improving effectively and reducing adverse side effects. The evidence for non-pharmacological treatment of ADHD remains mixed, there is some evidence to support the removal of food supplements from the diet of YP with ADHD and combination of psychological treatments and parenting groups with medication could have an added effect. All general psychiatrists should be aware of this disorder and be comfortable with making the diagnosis and treating both children and adults with ADHD.

Key Points

• ADHD is a common neurodevelopmental disorder which is possibly under-recognised in children and adults
• ADHD is easy to treat with 95% of correctly diagnosed patients responding to treatment
• To ensure the accuracy, a diagnosis of ADHD should be made following a multi modal assessment which is carried out by a multidisciplinary team trained in ADHD
• In younger children there is evidence to support that parenting groups and psychological treatment is effective, although the evidence is mixed regarding if combination with medication could have an added effect
• All general psychiatrists should be aware of and comfortable with making the diagnosis of ADH D and treating both children and adults

–Journal of the Malta College of Pharmacy Practice