If ADHD is accompanied by other conditions (co-morbidities) ADHD can be difficult to diagnose.
For example, children with ADHD may also have a specific learning disability, which means they have trouble mastering language or certain academic skills, such as reading or maths.
ADHD, in itself, is not a specific learning disability. But because it can interfere with concentration and attention, ADHD can make it more challenging for a child with learning disability to do well in school.
Disorders that can accompany ADHD:
Learning disabilities affect approximately 30 to 50 percent of people with ADHD.
In preschool years, these disabilities include difficulty in understanding certain sounds or words and / or difficulty in expressing oneself in words.
In school reading or spelling disabilities, writing and maths disorders may appear. Dyslexia, a neurologically-based disorder that inhibits orderly achievement and processing of linguistic information, is also a widespread co-morbidity.
Oppositional Defiant Disorder (ODD)
As many as 40 to 60 percent of all children with ADHD – mostly boys – have ODD.
These children may appear defiant, stubborn, non-compliant, have outbursts of temper, or become belligerent. They may also argue and refuse be disobedient.
Conduct Disorder (CD)
About 20 – 40 percent of children with ADHD may eventually develop CD, a more serious pattern of antisocial behaviour.
These children may violate the basic rights of other people by frequently lying, stealing, fighting with or bullying others, may also be aggressive towards animals, destroy property, break into people’s homes, commit thefts, carry or use weapons or engage in vandalism. These people are at greater risk for substance use experimentation, and later dependence and abuse.
The need immediate help as they are at a real risk of getting into trouble at school or with the police.
Anxiety and Depression
ADHD is often accompanied by anxiety or depression.
If the anxiety or depression is recognised and treated, you'll be better able to handle the challenges that accompany ADHD.
Conversely, effective treatment of ADHD can have a positive impact on anxiety as you'll be better able to master tasks at hand.
There are no accurate statistics on how many people with ADHD also have bipolar disorder.
Differentiating between ADHD and bipolar disorder can be difficult. There are some symptoms that can be present both in ADHD and bipolar disorder, such as a high level of energy and reduced need for sleep.
In its classic form, bipolar disorder is characterised by mood cycling between periods of intense highs and lows.
Of the symptoms differentiating these two, elated mood and grandiosity are distinguishing characteristics in bipolar disorder.
A very small proportion of people with ADHD have a neurological disorder called Tourette syndrome.
Symptoms include various nervous tics and repetitive mannerisms, such as eye blinks, facial twitches, or grimacing. Others are frequent throat clearing, snorting, sniffing or barking out words.
These behaviours can be controlled with medication.
Autism Spectrum Disorders
This term refers to Autism, Asperger’s syndrome, Pervasive developmental disorders, and high-functioning Autism.
ADHD and especially Asperger’s syndrome are closely related disorders which share many similar characteristics. In both, there is trouble with self-talk, self-awareness, the reading of social cues, and the demonstration of empathy. Both groups generalise rules poorly, and do better with predictability and routine.