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 in Adults From Other Coexisting Conditions

Since ADHD often coexists with other disorders we’ve included here descriptions of the more common co-morbidities:

Mood Disorders 

Bipolar Disorder

Traditionally the distinction between ADHD and bipolar disorder has been fairly easy to make. Bipolar disorder has been associated with euphoriagrandiosity 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-calledultradian version 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 (CG72,5.16.2).

More Information:


  • Affective states:  emotional or feeling experiences
  • Euphoria: a sense of exaggerated elation and happiness
  • Grandiosity: an exaggerated sense of one’s own importance, power, and knowledge
  • Hypomania: a persistently elevated mood without the accompanying psychotic symptoms usually associated with mania
  • Labile: unstable (e.g. mood swings)
  • Ultradian: abrupt mood shifts of less than 24 hours duration


A volatile and irritable mood is frequently seen in adult ADHD and is not usually the consequence of coexisting depression or bipolar disorder. The overlap of mood symptoms does mean that care must be taken to exclude the possibility of a major affective disorder and that mood lability does not occur solely within the context of such disorders. Attending to the time-course of the symptoms and psychopathology can help to distinguish the two. Early onset, chronic trait-like course, frequent mood swings throughout the day, no recent deterioration or severe exacerbation frequently accompany ADHD, whereas extreme low or high moods, sustained mood change for long periods of time and recent onset are more indicative of a primary affective disorder. Some individuals previously diagnosed with atypical depression, cyclothymia or unstable emotional personality disorder will have a primary diagnosis of ADHD (CG72, 5.16.2).

More Information:

Anxiety disorders

(eg agoraphobia, social anxiety disorder and including obsessive-compulsive disorder)

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 (CG72, 5.16.3).

More Information:

Personality Disorders

{Including antisocial personality disorder and borderline personality disorder)

The diagnostic issue is to recognise when there is evidence for ADHD, that is whether the operational criteria were fulfilled in childhood and whether ADHD symptoms that started in childhood have persisted and continue to bring about significant impairments. While the diagnostic focus should be on the main symptoms that define inattention, hyperactivity and impulsivity it is also important to remember that mood instability and impulsivity are commonly seen in adults with ADHD. Care must be taken to distinguish between uncontrolled, impulsive, oppositional and antisocial behaviours that arise in the context of a specific ADHD syndrome from those that do not. For this reason it is often useful to make particular enquiries about symptoms that are more specific to ADHD such as short attention span, variable performance, distractibility, forgetfulness, disorganisation, physical restlessness and over-talkativeness rather than focus only on the occurrence of maladjusted and disruptive behaviours (CG72, 5.16.1).

Antisocial Personality Disorder

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’.

More Information:

Borderline Personality Disorder

A pervasive pattern of instability of interpersonal relationships, self-image and affects, and marked impulsivity beginning by early adulthood and present in a variety of contexts, as indicated by five (or more) of the following: Frantic efforts to avoid real or imagined abandonment; a pattern of unstable and intense interpersonal relationships characterised by alternating between extremes of idealisation and devaluation; identity disturbance, markedly and persistently unstable self-image or sense of self; impulsivity in at least two areas that are potentially self-damaging (for example, spending, sex, substance abuse, reckless driving, binge eating); recurrent suicidal behaviour, gestures, or threats, or self-mutilating behaviour; affective instability due to a marked reactivity of mood (for example, intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days); chronic feelings of emptiness; inappropriate, intense anger or difficulty controlling anger (for example, frequent displays of temper, constant anger, recurrent physical fights); transient, stress-related paranoid ideation or severe dissociative symptoms.

More Information:

Psychotic Disorders

Severe inattention may rarely mimic the thought disorder symptoms seen in some psychoses, such as derailment, tangential thought processes, circumstantiality and flight of ideas. Careful monitoring of both psychotic symptoms and ADHD symptoms is advised but it may be difficult to distinguish residual symptoms of a major mental illness from persistence of ADHD symptoms (CG 72,5.16.4).


Typically, the problems of schizophrenia are preceded by a ‘prodromal’ period. This is often characterised by some deterioration in personal functioning. Difficulties may include memory and concentration problems, social withdrawal, unusual and uncharacteristic behaviour, disturbed communication and affect, bizarre ideas and perceptual experiences, poor personal hygiene, and reduced interest in and motivation for day-to-day activities.

More Information:

Developmental Disorders

Specific learning difficulties

  • Dysgraphia: writing difficulty that persists despite practice and regardless of an ability to read.  As well as poor handwriting, people with dysgraphia may have difficulty with fine motor skills, such as tying shoe laces, they may also have poor spelling and may write the wrong word when trying to put their thoughts on paper, and they may need to talk to themselves while trying to write.

More information can be found here:

  • Dyspraxia: difficulty with movement and coordination leading to clumsiness, and also problems with language, perception and organising thoughts.  It is unrelated to intelligence.

More Information:

  • Dyscalculia: difficulty performing mathematical calculations, following sequential directions, reading timetables, telling and keeping track of time, handling money, remembering faces and names, and difficulty distinguishing between left and right.  Sometimes people with dyscalculia may have above average reading and writing skills, and a good visual memory for the printed word.
    More Information:,3343,en_2649_35845581_34495560_1_1_1_1,00.html)

  • Dyslexia: difficulties with accurate word recognition and with spelling that are unrelated to levels of intelligence.  There may also be problems with reading comprehension, using a pencil to write, and distinguishing between left and right.
    More Information:

Autistic Spectrum Disorders

These disorders impact the way that a person communicates with and relates to other people.  They have trouble reading social cues and difficulty with recognising other people’s feelings.  They may also have a very limited range of interests and a pattern of repetitive behaviours. The disorders can range from the severe form, Autism, through to a much milder form called Asperger syndrome.

More Information:

Tourette’s syndrome

This was first described by a French doctor called Georges Gilles de la Tourette.  People with this syndrome 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 may 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:{5CE0C69B-C7CB-4FC5-91B5-0E94A57B3EF9}


About one third of people with epilepsy, particularly people with partial epilepsy of temporal and frontal lobe origin (abnormal electrical activity that only occurs in the temporal or frontal lobes), as well as those with primary generalised epilepsy (burst of abnormal electrical activity throughout the brain), may also have ADHD. Absence epilepsy (usually only seen in children and adolescents) can cause lapses in attention which could be misdiagnosed as predominantly inattentive ADHD.

More Information:

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 of 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.

More Information:

Sleep disorders

The symptoms of sleep disorders (eg inattentiveness, moodiness and distractability) 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 or depression which can negatively impact the quality of sleep and worsen the symptoms of ADHD, whilst others may have a co-existing sleep disorder which can also make the symptoms of ADHD worse.

The two sleep disorders that are commonly associated with ADHD are Restless Leg Syndrome (RLS) and Periodic Limb Movements during Sleep (PLMS).  There is also a possibility that RLS and PLMS may be more linked with the Hyperactive/Impulsive and Combined ADHD subtypes and they may also be more common in people who have both Tourette’s Syndrome and ADHD, although these relationships and their causes are currently still being researched.

The following descriptions were taken from ‘Review of the Possible Relationship and Hypothetical Links Between Attention Deficit Hyperactivity Disorder (ADHD) and the Simple Sleep Related Movement Disorders, Parasomnias, Hypersomnias, and Circadian Rhythm Disorder’ Walters AS, Silvestri R, Zucconi M, Chandrashekariah R, Konofal E. Journal of Clinical Sleep Medicine, 2008 Dec 15; 4(6) 591-600

More Information:

Restless Leg Syndrome (RLS)

 Restless Leg Syndrome (RLS) is a common sensorimotor disorder characterized by an irresistible urge to move the legs, which is often accompanied by uncomfortable sensations in the legs or, less frequently, other body parts. These sensations are worse at rest, relieved by movement and worse in the evening or night and at rest. In RLS patients frequently experience insomnia from the leg discomfort and the need to move around. The diagnosis of RLS is based on the revised RLS criteria developed by the International Restless Leg Syndrome Study Group (IRLSSG). Although RLS is traditionally considered a disorder of middle to older age, several case series show that it may occur in childhood.  Patients with RLS also frequently have a related sleep disorder called Periodic Limb Movements in Sleep (PLMS).

Periodic Limb Movements in Sleep (PLMS)

Periodic Limb Movements in Sleep (PLMS) is defined as movements that last 0.5–10 seconds and recur every 5 to 90 seconds.  These movements usually affect the legs although the arms may be involved as well. Typical movements consist of simultaneous flexions of the hips, knees and ankles. Eighty percent of adult patients with RLS have PLMS.

More Information:

Welcome to our website! If there is anything on this page you would like to discuss, or if you have any questions, please join us in our Forum here.

Last review date: 13/04/2011

Next review due: 13/04/2012

What is ADHD?   Symptoms  Diagnosis & Treatment   Complementary Therapies   Home

Comments are closed.

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 1,028 other followers

Latest Tweets

%d bloggers like this: