Information provided on this website is intended for your general knowledge and is not meant to be a substitute for professional medical advice and treatment. You should never disregard professional medical advice or delay in seeking an assessment or medical treatment because of something you may have read on this site. You should also not use the information on this web site or the information on links from this site to diagnose or treat ADHD and/or co-morbidities, in yourself or others, without consulting a qualified adult ADHD specialist.

Differentiating ADHD From Other Coexisting Conditions

Comorbidities are one or more disorders that are present along with the primary disorder of ADHD.  A comorbidity may be independent of ADHD or it may be related.  The presence of comorbidities can affect the presentation of ADHD symptoms and can sometimes even mask the presence of ADHD. This makes diagnosis difficult to the extent that in the latter case some adults diagnosed with a disorder may not have had the core disorder, ADHD, identified and thus their treatment may be ineffective.  Some of the comorbidities associated with ADHD may be a result of the impact of ADHD upon a person’s life (e.g. problems with work performance leading to anxiety).  Other disorders may occur simultaneously (e.g. ADHD and Dyslexia).

Mood Disorders 

The most common mood disorders associated with ADHD are bipolar disorder, cyclothymia, depression  and self-harm.

1. Bipolar Disorder: Traditionally the distinction between ADHD and bipolar disorder has been fairly easy to make. Bipolar disorder has been associated with euphoria, grandiosity and a cycling course, with each episode lasting for several days at least. ADHD, by contrast, has been regarded as a persisting disability in which euphoria is not particularly a feature. The goal-directed over-activity of mania is usually seen to be in contrast with the disorganised and off-task activity of ADHD. Individuals with ADHD often have difficulty sleeping but unlike mania or hypomania they complain about their lack of sleep and often feel exhausted during the day. In general individuals with ADHD report that they cannot function effectively and this is often associated with chronic low self-esteem, very different from the feelings of heightened efficiency seen in mania. In ADHD thoughts are often described as ‘on the go’  all the time, but unlike mania or hypomania, these are experienced as unfocused, muddled and inefficient and there is no subjective sense of improved efficiency of thought processes.

There has, however, been a broadening of the concept of bipolar disorder, to include cases where the mood change is not euphoria but irritability or chronic mixed affective states, and where the cyclical nature consists of many changes within a single day (indistinguishable from a volatile, labile mood). This leads to a very considerable similarity in formal definitions between this so-called ultradian version (abrupt mood shifts of less than 24 hours duration) of bipolar disorder and ADHD. An unstable and over-reactive mood is very commonly seen in ADHD, even though it is not part of the diagnostic definitions, and the development of an oppositional disorder, in which frequent tantrums are common, can be described as an ‘irritable’ state and therefore contributes to a bipolar diagnosis.

One of the main questions relates to the validity of a diagnostic concept broadly defined as bipolar disorder, or whether mood instability/irritability in the presence of ADHD may be more adequately described by a new dimension, such as mood dysregulation.  Until the relevant empirical data become available, the classic definition of mania should be maintained: a diagnosis of bipolar disorder requires euphoria, grandiosity and episodicity, and the differential between ADHD and bipolar disorder remains explicit (1). More information is available from the NHS Choices website, the Bipolar UK website and the website for the Royal College of Psychiatrists (Accessed 15/5/2017).

2. Cyclothymia: People with cyclothymia will have a history of mood swings that range from mild depression to periods of euphoria and excitement when they don’t need much sleep.  Most people’s symptoms can be mild enough that they do not seek mental health treatment, so cyclothymia often goes undiagnosed and untreated. However, the mood swings can disrupt personal and work relationships. Cyclothymia can progress into bipolar disorder and people often don’t seek treatment until this late stage. People with cyclothymia will have persistent and frequent mood swings and will have no more than two months in a row that are symptom free. The causes are unknown but there is probably a genetic link since cyclothymia, clinical depression and bipolar all tend to run in families. In some people, traumatic events or experiences (such as severe illnesses or long periods of stress) may act as a trigger. Cyclothymia may continue as a lifelong condition or it may disappear with time. More information is available on the NHS Choices website (Accessed 15/5/2017).

3. Depression: This is a real illness with real symptoms and it isn’t something you can snap out of by pulling yourself together. Depression affects people in different ways and can cause a wide variety of symptoms. They range from lasting feelings of unhappiness and hopelessness, to losing interest in the things you used to enjoy and feeling very tearful. Many people with depression also have symptoms of anxiety. There can be physical symptoms too, such as feeling constantly tired, sleeping badly, having no appetite or sex drive, and various aches and pains. The symptoms of depression range from mild to severe. At its mildest, you may simply feel persistently low in spirit, while severe depression can make you feel suicidal, that life is no longer worth living. More information is available on the NHS Choices website (Accessed 15/5/2017).

4. Dysthymia: This is a chronic depressive state (two years or more duration) which is not the consequence of a partly resolved major depression and does not meet the diagnostic criteria for major depression. It is sometimes called persistent depressive disorder or chronic depression. Some of the symptoms are feeling low most days, trouble concentrating, difficulty making decisions, low energy levels, fatigue, loss of appetite or overeating and low self-esteem.

5. Self-harm: ADHD is a potential risk factor for self-harm whilst the latter is a significant health problem in the UK and is one of the most common reasons for visits to A&E. (1) Self-harm is when somebody intentionally damages or injures their body. It’s usually a way of coping with or expressing overwhelming emotional distress. Sometimes when people self-harm, they feel on some level that they intend to die. Over half of people who die by suicide have a history of self-harm. However, the intention is often to punish themselves, express their distress or relieve unbearable tension. Sometimes the reason is a mixture of both. Self-harm can also be a cry for help. There are many different ways people can intentionally harm themselves, such as: cutting or burning their skin, punching or hitting themselves, poisoning themselves, misusing alcohol or drugs, deliberately starving themselves or binge eating, or by excessively exercising. People often try to keep self-harm a secret because of shame or fear of discovery. For example, if they’re cutting themselves, they may cover up their skin and avoid discussing the problem. It’s often up to close family and friends to notice when somebody is self-harming, and to approach the subject with care and understanding. Note: a review of the relationship between ADHD and suicidality found that ADHD symptoms occur more frequently in suicidal populations and may be a reason for completed suicide. In sum, there is a positive relationship between ADHD and risk to self while numerous studies have indicated that self-harm predicts suicide. Suicide risk among self-harm patients is “hundreds of times higher than in the general population” (2). More information is available from the references below as well as the NHS Choices website. (Accessed 15/5/2017)

Please note: If you’re reading this because you have, or have had, thoughts about taking your life, it’s important you ask someone for help. It’s probably difficult for you to see at this time, but you’re not alone and not beyond help.

Many people who’ve had suicidal thoughts say they were so overwhelmed by negative feelings they felt they had no other option. However, with support and treatment they were able to allow the negative feelings to pass.

Speak to someone you trust because they may be able to help you find some breathing space, or call the Samaritans (24 hour support service) on 116 123, or go to your closest A&E and tell the staff how you feel, or ring NHS 111, or make an urgent appointment to see your GP.  Remember you are not alone and not beyond help. There is more information on the NHS Choices website. (Accessed 15/5/2017)

Anxiety disorders

Individuals with ADHD commonly report high levels of anxiety on rating scales. However, a more detailed enquiry about the psychopathology shows that in some cases the ADHD syndrome mimics some aspects of anxiety. Individuals with ADHD may have difficulty coping with social situations because they are unable to focus on conversations; difficulty travelling because they are unable to organise the journey; and difficulty shopping because they may become irritable waiting in queues and because they may forget things and be highly disorganised. Problems with simple everyday tasks that most people take for granted are a source of considerable concern and are often accompanied by avoidance of stressful tasks and poor self esteem.

In combination with ceaseless mental activity, these legitimate concerns and responses may take on the appearance of a mild to moderate anxiety state, although lacking the systemic manifestations of anxiety disorders. An important distinction is to consider whether the symptoms have a similar onset and time course to ADHD or whether they arise episodically and in response to stressors, which is characteristic of anxiety (1).

Even though some aspects of ADHD may mimic anxiety, anxiety can also be comorbid with ADHD. The 4 anxiety disorders most likely to be comorbid with ADHD are generalised anxiety disorder, separation anxiety disorder, social anxiety disorder and post traumatic stress disorder.

1. Generalised anxiety disorder (GAD): This disorder is also known as ‘chronic worrying’ or ‘free floating anxiety.’ People with this condition feel as if they are in a constant state of high anxiety (for 6 months or more) and feel as if their thoughts are racing with difficulty in focusing and concentrating. They have problems with sleeping and may also have work and relationship difficulties. More information is available from Anxiety UK(Accessed 17/5/2017)

2. Separation anxiety disorder: This usually develops in childhood and can persist into adulthood, but it also has a relatively high prevalence rate in adults many of whom developed it in adulthood although it has only been identified as such fairly recently.  People with separation anxiety can experience high levels of disability. Affected adults experience intense fears that harm will befall close attachment figures, engaging in a range of strategies to maintain close contact with them. When faced with real or feared separations from family members, persons with separation anxiety are at risk of developing panic attacks (3).

3. Social anxiety disorder: Social anxiety disorder is persistent and overwhelming fear of or anxiety about one or more social situations (e.g. eating or drinking in a public place) where embarrassment may occur. This fear or anxiety is out of proportion to the actual threat posed. Although anxiety about some social situations is common in the general population, people with social anxiety disorder can worry excessively about them and can do so for weeks in advance. They may also ruminate on social events they perceive have gone wrong for weeks afterwards. Usually the condition causes significant impairment in social, occupational (e.g. talking to authority figures, or writing documents in front of others) or other areas of functioning. Some of the symptoms are unable to think straight or the mind goes blank, stumbling over words, poor concentration and poor short term memory, talking excessively and missing appointments or events.  More information is available on the NHS Choices website (Accessed 15/5/2017)

4. Post-traumatic stress disorder (PTSD): This is a disorder caused by very stressful, frightening or distressing events.  Someone with PTSD often relives the traumatic event through nightmares and flashbacks, and may experience feelings of isolation, irritability and guilt.  They may also have problems sleeping and may find concentrating difficult. These symptoms are often severe and persistent enough to have a significant impact on day to day life.  More information about the causes, symptoms, and treatment is available on the NHS Choices website. (Accessed 15/5/2017)

Personality Disorders

The chronic trait-like characteristics of ADHD symptoms that start in early childhood and persist into adulthood are frequently mistaken for traits of a personality disorder. This happens for two disorders in particular of the cluster B personality disorders, namely antisocial and borderline personality disorders, because these two include symptoms that are commonly associated with adult ADHD, for example mood instability, impulsivity and anger outbursts (1). Some adults with ADHD, however, may also have a comorbid personality disorder; possibly because they share common biological influences.

1. Antisocial Personality Disorder (ASPD): This disorder is characterised as a ‘pervasive pattern of disregard for and violation of the rights of others that has been occurring in the person since the age of 15 years, as indicated by three (or more) of seven criteria, namely: a failure to conform to social norms; irresponsibility; deceitfulness; indifference to the welfare of others; recklessness; a failure to plan ahead; and irritability and aggressiveness’ (4).  People with ASPD may have traits of impulsivity and high negative emotionality along with interpersonal and social difficulties.  More information about causes, diagnosis, and treatments are available in the NICE guidance “Antisocial Personality Disorder: Treatment, Management and Prevention.” (Accessed 17/5/2017)

2. Borderline Personality Disorder (BPD): This is diagnosed when there is a pervasive pattern of instability of interpersonal relationships, self-image and moods, rapid fluctuations from confidence to despair, fear of rejection, frantic efforts to avoid real or imagined abandonment, identity disturbance, and a strong tendency to suicidal thinking and self-harm with risk of suicide.  There may also be temporary psychotic symptoms including delusions and hallucinations.  The severity of the symptoms varies considerably from one person to another and some people may recover over time whilst others may continue to experience difficulties. More information about BPD including prevalence rates and treatments are available in the NICE Guidance “Borderline Personality Disorder: recognition and management” and the NHS Choices website. (Accessed 17/5/2017)

Psychotic Disorders

1. Schizophrenia: this disorder may coexist with ADHD but it does not occur any more frequently in people with ADHD than in the general population (approximately 1 in every 100).  However, people with schizophrenia often have problems with attention and activity levels which may make it difficult to determine whether or not ADHD is also present. Also,  Careful monitoring of both psychotic symptoms and ADHD symptoms is advised but it may be difficult to distinguish some symptoms of schizophrenia from ADHD (1). The disorder may develop slowly and the signs can be hard to identify at first (such as becoming socially withdrawn and changes in sleeping patterns).  A person with schizophrenia may also have muddled thoughts, changes in behaviour, hallucinations and delusions. More information about symptoms, causes, diagnosis and treatment are available from NHS Choices  and the Royal College of Psychiatrists. (Accessed 17/5/2017)

Developmental Disorders

Specific learning difference (SpLD)

These are neurological disorders which affect some aspects of the way people learn. The most common SpLD’s are Dysgraphia, Dyspraxia, Dyscalculia and Dyslexia (many universities place ADHD within SpLD group).  Anybody with an SpLD is just as able as anybody else except in one or two areas of learning depending upon whichever of the SpLD’s is present.  These disorders are unrelated to levels of intelligence.  People with one of these disorders are also more likely to have ADHD (or an Autistic Spectrum Disorder) than people who do not have an SpLD.

1. Dysgraphia: This is a disorder that causes problems with written expressions despite practice and regardless of ability to read.  As well as poor handwriting, people with dysgraphia have difficulty with spelling, with grammar, and trying to put their thoughts on paper.  They may need to talk with themselves while writing.  People  also have difficulty with fine motor skills  such as a difficulty holding a pen.  More information can be found on the University of Bath website. (Accessed 17/5/2017)

2. Dyspraxia: People with this disorder have difficulty with movement and coordination leading to clumsiness, poor balance, poor hand to eye coordination, poor manual dexterity and may use either hand for different tasks at different times.  They may also have problems with language, perception and organising thoughts.  These difficulties are unrelated to intelligence. More information is available from the Dyspraxia Foundation. (Accessed 17/5/2017)

3. Dyscalculia: This disorder affects the ability to acquire basic arithmetic skills and approximately 4-6% of the population have dyscalculia.  Someone with dyscalculia has difficulty performing mathematical calculations and sometimes can’t get past long division, difficulty understanding place value and the role of zero, difficulty counting backwards, difficulty following sequential directions, reading timetables, telling and keeping track of time, handling every day money transactions (e.g. giving change & managing a bank account), remembering faces and names, identifying clothes sizes and difficulty distinguishing between left and right.  Dyscalculia can cause difficulties at work (e.g. filling out time sheets, managing a diary, budgeting & timekeeping). Sometimes people with dyscalculia may have above average reading and writing skills, and a good visual memory for the printed word. There is more information on the British Dyslex!a Association website. (Accessed 18/5/2017)

4. Dyslexia: This disorder causes difficulties with reading, writing and spelling and about 1 in every 10 people are affected to some degree.  Someone with Dyslexia may read and write slowly, may confuse the order of letters and may write them the wrong way round.  They may also have difficulties following directions, with time perception and with planning and organisation. People with Dyslexia often have strong visual creative and problem solving skills.
More information including where to get help and workplace information is available on the British Dylex!a Association website. (Accessed 19/5/2017)

Autism Spectrum Disorders (ASD)

ASD is a group of complex neurodevelopmental disorders.  In the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) the umbrella diagnostic term used was “Pervasive Developmental Disorders” under which Autistic Disorder, Asperger’s Syndrome and Pathological Demand Avoidance (PDA) as well as other disorders were listed in sub categories as separate disorders. Then DSM-IV was finally updated and published in 2013 as DSM-V. DSM-V now includes Autistic Disorder, Asperger’s Syndrome and PDA as part of ASD rather than as part of separate disorders.

Some organisations and health professionals, however, do not use the DSM-V to describe ASD, instead they use the International Classification of Diseases (ICD-10).  ICD-10 has not yet been updated (ICD-11 is expected in 2018) so until the ICD is updated and published you will still encounter the older terms of Autistic Disorder, Asperger’s Syndrome, PDA etc.  After 2018 when the DSM-V and the ICD-11 have become aligned the term Autism Spectrum Disorder will be the one that is commonly used.

ASD affects about 1 in every 100 people.  The severity of the disorder ranges from severe to mild and it is based upon the degree to which social communication and interaction, dislike of change in activities and surroundings, and repetitive patterns of behaviour impact a person’s daily functioning.    More information is available on The National Autistic Society website (ICD-10) and the NHS Choices website (DSM-V). (Accessed 19/5/2017)

Tourette syndrome (TS)

This was first described by a French doctor called Georges Gilles de la Tourette.  It is a complex neurological inheritable condition that may form part of a spectrum that includes OCD & ADHD.  People with TS have motor and vocal tics  such as rapid, repetitive and meaningless blinking, head shaking and grimacing, sniffing, throat clearing and grunting.  Some people are very mildly affected, while a small percentage (about 10% of people with TS) have more severe symptoms which make the disorder more noticeable and disabling (such as uncontrollable bursts of profanity or the repetition of words or sounds).   In addition to being linked with ADHD, it is also often linked with obsessive compulsive disorder. More information about possible causes, symptoms, diagnosis and managing TS is available from the Tourettes Action website and from the NHS Choices website (Both accessed 19/05/2017)


A longitudinal study found that people with ADHD are at much greater risk for being overweight or obese. The extremely high rate of comorbid ADHD among obese people was noted in a study in Israel where the researchers strongly advised physicians to check for or refer obese patients to clinical psychologists to assess ADHD and other mental health disorders, because treating ADHD could help with treating obesity.  A clinical study in Turkey found that children and teenagers with ADHD have a much lower tolerance to stress and frustration than those without ADHD and thus may binge on junk food possibly as a form of self-medicating. In addition to this, ADHD was correlated with both malnutrition as well as being overweight and obese. The researchers stated that this shows ADHD to be a major risk factor not only for obesity but also for eating disorders in general (7).

Eating Disorders

Eating disorders are complex and the causes are not yet fully understood other than that many different risk factors (genetic, biological, psychological, environmental and social) are involved. There seems to be a strong association between ADHD and eating disorders.  The relationship, however, between ADHD and eating disorders is complex and not yet clearly understood. It is possible that inattention can lead to confusion about adequate food intake whilst impulsivity and hyperactivity symptoms can lead to binge eating and purging but more research is needed to better understand the association between ADHD and Eating Disorders (4).  Some people will have more than one type of eating disorders and symptoms can change over time. Eating Disorders are serious but treatable. Brief descriptions are given below but for more information about the types of eating disorders, the behavioural signs, the symptoms as well as information about help and treatment see the website for beat: beating eating disorders (Accessed 23/05/2017).

1. Anorexia Nervosa: This is a serious but treatable disorder where people try to keep their body weight as low as possible.  It can affect boys and men as well as girls and women.  Some people with anorexia think they are overweight when in reality they are not, and many will try to hide their behaviour from others. Anorexia can cause severe physical problems and can also impact relationships with family and friends.

2. Bulimia Nervosa: people with Bulimia eat large quantities of food and then vomit, take laxatives or diuretics to prevent gaining weight. This cycle can dominate their lives and they may also try to hide their behaviour and they are also unlikely to seek help.

3. Binge-Eating: people will eat very large quantities of food over a short period of time and will often do so when they are not actually hungry.  These ‘binges’ usually are planned and carried out in private and are often followed by feelings of guilt and shame.  People who binge do not purge themselves unlike those suffering from Bulimia.  Binge eating affects men and women equally.

Alcohol/Drug Misuse

Addiction involves a complex interaction between repeated exposure to drugs and alcohol, genetic and developmental predisposition and environmental conditions such as drug availability and social and economic factors.  ADHD is strongly related to cigarette smoking, and this may represent an attempt at self-medication because nicotine impacts levels of dopamine within the brain.  Nicotine dependence, however, could increase the risk for those who are vulnerable to misusing alcohol, cannabis and other substances, and thus possibly result in the development of addiction disorders. The hyperactive subtype of ADHD, associated with conduct disorder or antisocial personality disorder, is also strongly linked with substance abuse. It should be noted, however, that people receiving treatment for their ADHD are far less likely to misuse drugs and alcohol than those whose ADHD has not been recognised and treated. You can find out more information about drugs and alcohol on the website for Talk to Frank: Friendly, confidential drugs advice and also NHS Choices (both accessed 23/05/2017).

Other Addictions

1. Gambling Disorder: people with this disorder are unable to control urges to gamble, and in fact the NHS says that the thrill of gambling creates a natural high that can be addictive.  Gambling has become easier with the growth of the Internet.  Many studies have shown that people with ADHD are at increased risk for developing this disorder and also that people with ADHD may have more severe gambling problems.  Screening for ADHD should be part of gambling treatment and gambling is treatable.  More information about gambling including where to get help is available from GamCare and from NHS Choices (both accessed 23/05/2017).

2. Compulsive Sexual Behaviour Disorder:  The defining feature of this condition is that the need for repetitive and short-term sexual gratification overrides its potential long-term harm, distress and impairment. It is also known as sex addiction or hypersexuality.  People with ADHD tend to have problems with sex including making impulsive sexual choices whilst others engage in thrill seeking behaviour which can include problematic behaviours such as over-using pornography and having multiple affairs. Some feel that people with ADHD have problematic sexual behaviour as a way to self-medicate, feel better when bored or frustrated, or to avoid feelings of anxiety and low self-esteem (8).

3. Internet Gaming Disorder (IGD): this was originally seen as part of Problematic Internet Use (PIU).  IGD is included in DSM-5 but as a subject that needs further research because while it is recognised that it is not part of PIU there is still not enough known about internet gaming to give it the status of an official diagnosis. Despite the fact that data about IGD also included data about other problematic internet uses, it does appear that IGD is associated with symptoms of ADHD. There is a study that shows that approximately 39% of young adults with IGD also meet the criteria for ADHD (6).

4. Problematic Internet use (PIU):  This is a somewhat controversial listing and it’s not listed in DSM-5 because on the one hand it describes an addiction to a delivery mechanism rather than an actual substance and on the other it is used for a variety on online behaviours such as gambling, shopping, and sexual activities.  Still overall there is a strong association between ADHD and PIU (6).


Two to three times higher rates of ADHD have been found in people with epilepsy with equal rates for males and females.  There is some evidence that the  predominantly inattentive type of ADHD is more common in people with epilepsy than the combined type of ADHD but more research is needed to understand the differences in ADHD subtypes in epilepsy.  It seems likely that ADHD is comorbid with epilepsy (rather than a result of epilepsy) because ADHD symptoms are frequently present before onset of seizures. Earlier age of seizure onset is associated with greater cognitive deficits including attention. Methylphenidate may be an effective treatment for children with epilepsy and ADHD but the effectiveness seems to be less than for children with ADHD without epilepsy. There is very limited data for other ADHD medications.  In addition, people should be warned that there is a low risk of increased seizures with methylphenidate and atomoxetine.  Further research is needed (5).  More information about epilepsy is available from NHS Choices and more information about epilepsy and ADHD from the Epilepsy Society (both accessed 23/05/2017).

Sleep disorders

People with ADHD are two to three times more likely to have sleep disorders than people without ADHD; they may have problems falling asleep, trouble staying asleep, delayed sleep phase, restless sleep, breathing difficulties, nightmares, and finally and not surprising trouble waking up in the morning and daytime sleepiness.

The symptoms of sleep disorders (eg inattentiveness, hyperactivity, moodiness and distractibility) can be confused with those of ADHD, so a misdiagnosis of ADHD when the core problem might be a sleep disorder is a possibility.  To make things more confusing, however, some people with ADHD may have co-existing anxiety, depression or substance misuse which can also negatively impact the quality of sleep and worsen the symptoms of ADHD, whilst others may have a co-existing sleep disorder which again can also make the symptoms of ADHD worse.

Researchers are still not sure how ADHD, co-morbidities and sleep problems are related, and research is still ongoing to develop a better understanding of how the different areas of the brain interact and how these different areas combine in a way that affects sleep in people with ADHD.

Since sleep disorders can confuse the diagnosis of ADHD, and  since they are also very common in people with ADHD, and since sleep problems can have a negative impact upon the effectiveness of treatment, it would be helpful if screening for sleep problems became part of the diagnostic process.

The sleep disorders that are commonly associated with ADHD are Restless Leg Syndrome (RLS), Periodic Limb Movement during Sleep (PLMS) and Circadian Rhythm Sleep Disorders.

1. Restless Leg Syndrome (RLS): The following description has been taken from the excellent factsheet that’s available on the website for the American National Institute of Neurological Disorders and Stroke (NINDS).

Restless legs syndrome (RLS), also called Willis-Ekbom Disease, causes unpleasant or uncomfortable sensations in the legs and an irresistible urge to move them.  Symptoms commonly occur in the late afternoon or evening hours, and are often most severe at night when a person is resting, such as sitting or lying in bed.  They also may occur when someone is inactive and sitting for extended periods (for example, when taking a trip by plane or watching a movie).  Since symptoms can increase in severity during the night, it could become difficult to fall asleep or return to sleep after waking up.  Moving the legs or walking typically relieves the discomfort but the sensations often recur once the movement stops.  RLS is classified as a sleep disorder since the symptoms are triggered by resting and attempting to sleep, and as a movement disorder, since people are forced to move their legs in order to relieve symptoms.  It is, however, best characterized as a neurological sensory disorder with symptoms that are produced from within the brain itself.

RLS is one of several disorders that can cause exhaustion and daytime sleepiness, which can strongly affect mood, concentration, job and school performance, and personal relationships.  Many people with RLS report they are often unable to concentrate, have impaired memory, or fail to accomplish daily tasks.  Untreated moderate to severe RLS can lead to about a 20 percent decrease in work productivity and can contribute to depression and anxiety.  It also can make traveling difficult.

In most cases, the cause of RLS is unknown (called primary RLS).  However, RLS has a genetic component and can be found in families where the onset of symptoms is before age 40.  Specific gene variants have been associated with RLS.  Evidence indicates that low levels of iron in the brain also may be responsible for RLS.
Considerable evidence also suggests that RLS is related to a dysfunction in one of the sections of the brain that control movement (called the basal ganglia) that use the brain chemical dopamine.  Dopamine is needed to produce smooth, purposeful muscle activity and movement.  Disruption of these pathways frequently results in involuntary movements. 

More than 80 percent of people with RLS also experience periodic limb movement of sleep (PLMS). 

More information about RLS is available in the factsheet on the National Institute of Neurological Disorders and Stroke (NINDS) website (accessed 25/05/2017).

2. Periodic Limb Movement during Sleep (PLMS): PLMS (formerly known as nocturnal myoclonus) is frequently associated with nocturnal arousals of which patients are unaware and it often occurs with RLS (above). Partners sleeping in the same bed may be woken by uncontrollable brief jerks of the limbs occurring at approximately 20-40 second intervals.  These movements occur more often in the toes, feet and legs than the arms, and they are also associated with transient arousal or awakening from sleep.  These limb movements may be reported as the presenting symptom by the patient, but more often by the bed partner. Patients frequently report feeling unrefreshed following sleep. PLMS is associated with subjective diminished physical and psychological fitness on awakening, and with symptoms of daytime sleepiness, fatigue, and poor performance at work. More information is available from the Restless Leg Syndrome section of NHS Choices (accessed 25/05/2017).

3. Circadian Rhythm Sleep Disorders: Circadian rhythm refers to the body’s natural cycle of sleep and waking patterns. Circadian rhythm disorders are sleep disorders where there is a mismatch between circadian rhythms and required sleep– wake cycle. Thus there can be sleeplessness when trying to sleep at a time not signalled by the internal clock, and excessive sleepiness when needing to be awake. Some circadian disorders (jetlag and shift-work disorder) are due to an individual lifestyle, including work and travel schedules, that conflicts with the internal clock. Others are: (1) delayed sleep-phase syndrome (DSPS), where there is difficulty falling asleep before 2–3a.m. (sometimes later), and on days without work/school/college the preferred wake time is after 10a.m., resulting in sleep-onset insomnia and difficulty waking up in the morning on days when an early bedtime for an early start time is necessary (2) free-running sleep disorder, where there is a daily increment of sleep and wake times (getting later each day). This is often associated with insomnia of varying severity and daytime sleepiness. This information was taken from British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders (2010). (Accessed 25/05/2017)


People with ADHD are twice as more likely to have a comorbid diagnosis of asthma and this potentially could be due to a genetic association  in that a gene polymorphism of dopamine receptor D5 (DRD5) is associated with ADHD and also with some part of the immunological regulatory process which is involved in asthma development.  Much more research is needed to understand the relationship between asthma and ADHD but in the meantime collaborative treatment for people with both ADHD and asthma will be beneficial (9) since symptoms of asthma can exacerbate some symptoms of ADHD and vice versa.


1. National Institute for Health and Clinical Excellence (2008) Diagnosis and management of ADHD in children, young people and adults. NICE guideline (CG72)

2. Allely CS: The association of ADHD symptoms to self-harm behaviours: a systematic PRISMA review. BMC Psychiatry. 2014, 14:133

3. Silove DM, Marnane CL, Wagner R et al: The prevalence and correlates of adult separation anxiety disorder in an anxiety clinic. BMC Psychiatry. 2010, 10:31

4. Kaisari P, Dourish CT, Higgs S: Attention Deficit Hyperactivity Disorder (ADHD) and disordered eating behaviour: A systematic review and a framework for future. Clinical Psychology Review 53 (2017) 109–121

5. Williams AE, Giust JM, Kronenberger WG, et al: Epilepsy and attention-deficit hyperactivity disorder: links, risks, and challenges. Neuropsychiatric Disease and Treatment. 2016; 12: 287–296.

6. Starcevic V, Khazaal Y: Relationships between Behavioural Addictions and Psychiatric Disorders: What Is Known and What Is Yet to Be Learned?. Frontiers in Psychiatry 2017 Apr 7; 8: 53.

7. Weissenberger S, Ptacek R, Klicperova-Baker M, et al: ADHD, Lifestyles and Comorbidities: A Call for an Holistic Perspective – from Medical to Societal Intervening Factors. Frontiers in Psychology 2017; 8: 454.

8. Garcia JR, Mackillop J, Aller EL, et al:  Associations between Dopamine D4 Receptor Gene Variation with Both Infidelity and Sexual Promiscuity. PLOS ONE 5(11): e14162

9. Miyazaki C, Koyama M, Ota E, et al: Allergic diseases in children with attention deficit hyperactivity disorder: a systematic review and meta-analysis. BMC Psychiatry. 2017 Mar 31;17(1):120.



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What is ADHD? 


Diagnosis & Treatment         

Complementary Therapies         



Last review date: 25/05/2017

Next review due: 26/05/2020


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