Co-existing Conditions

Evidence-based information about adult ADHD

ADHD isn’t just about inattentiveness or hyperactivity/impulsivity…

Although the diagnostic criteria for ADHD are focussed on inattentiveness and/or hyperactivity/impulsivity, there are a number of other disorders which are commonly seen in adults with ADHD which add to the burden of the condition. Details of these are provided below and there is a downloadable PDF which has all these details at rthe bottom of the page.

Mood Disorders

There are a number of mood disorders associated with ADHD. These can include depression (three times more prevalent in adults with ADHD compared to adults without ADHD), dysthymia (a persistent, low mood which affects more than 10% of adults with ADHD), bipolar spectrum disorder (rates of co-morbid bipolar disorder in ADHD are between 5.1% and 47.1% ) or others. These mood problems aren’t necessarily due directly to ADHD, but commonly co-exist with it. ADHD itself can affect mood, and this is why sometimes it tales time to get a diagnosis of co-existing mood disorders.

Anxiety Disorders

The risk for anxiety disorders is higher in individuals with ADHD than in the general population with rates approaching 50%. These can include generalised anxiety disorder (GAD), post traumatic stress disorder (PTSD), obsessive compulsive disorder (OCD) and others. As with mood disorders, some of the behaviour traits associated with ADHD can be hard to distinguish from anxiety disorders, causing problems with diagnosis in some.

Emotional Dysregulation (ED)

People with ADHD often feel emotions more intensely than people without the condition. As many as 70% of adults with ADHD will also have ED. Studies on emotional dysregulation in adult ADHD have shown that ADHD patients are less able to regulate and control emotions than controls and that these emotional deficits influence quality of life more negatively than the ADHD core symptoms of inattention/hyperactivity alone. ED can manifest itself as extremely emotional reactions to even small challenges or setbacks.

Rejection Sensitive Dysphoria (RSD)

RSD is a condition where extreme emotional sensitivity and pain are triggered by the perception that a person has been rejected or criticised by other, sometimes important people in their life. Internally, RSD can feel like a full, major mood disorder complete with suicidal ideation and these feelings can develop extremely rapidly. Externally, RSD can come across as instantaneous rage, over-pleasing or complete avoidance at the person or situation responsible for causing the pain. RSD can even occur when a person expects rejection, but hasn’t gone through it yet.

Poor Working Memory

Many adults with ADHD have difficulty with their working memory. Working memory is a system in the brain with a limited capacity that can temporarily hold information. Working memory is important for reasoning, decision-making and behaviour. Working memory is different to short-term memory, as short term memory simply stores information for a brief period of time, whereas working memory retains information for a few seconds in order to reason, manipulate or comprehend it. Poor working memory in ADHD can lead to a poor prioritisation of relevant information, causing problems with recall (even seconds after receiving information), organisation, and distinguishing between important and unimportant things.

Time Blindness

Time blindness is a term actually invented to explain issues with ADHD. Adults normally develop a pretty good awareness of time and the ability to track its passing but people with ADHD can struggle with this, hence the name ‘time blindness’. Time blindness can show itself in people always being late, or sometimes always early (as a coping mechanism to avoid anxiety). Because many people with ADHD are just unaware of time, they cannot manage it successfully.

Oppositional defiant disorder (ODD)

Although more commonly associated with ADHD in childhood, many adults with ADHD also have ODD. People with ODD can be angry more often than not, and can argue regularly with loved ones or coworkers. Having ODD can feel like being angry at the world, and it can lead to a strong dislike for authority.


Not all of the conditions commonly associated with ADHD in adults are behavioural. In a study of adults requiring gastric bypass surgery due to obesity, 27% had inattentive ADHD which increased to 43% in those who were very obese. Those with ADHD in this study also lost less weight. Eating disorders such as binge eating or bulimia can co-exist with ADHD and it is thought that impulsive eating and reduced physical activity are to blame for this increased risk of ADHD.

Substance Abuse

Several studies have shown a strong connection between ADHD and substance abuse, including addiction. ADHD is 5 to 10 times more common in adult alcoholics than non-ADHD adults and in adults being treated for alcohol and substance abuse, the rate of ADHD is about 25%.


There is evidence from a number of studies that migraine and ADHD are linked. Evidence suggests that the link between migraines and ADHD is strongest in middle age, while one study reported that men with ADHD are twice as likely to have migraines than men without.

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