A new estimate of the global prevalence of adult ADHD suggests the condition could be more common than previously realized. This likely explains the recent and questioned increase in adults diagnosed.

An international team of researchers examined 57 studies, with a total of 21 million participants and found about 180 million adults likely have ADHD.

I am one of those people. Earlier this year I received an ADHD diagnosis at the fresh young age of 38.

"Focusing on ADHD in adults is a critical public health concern, as leaving it untreated can lead to long term social, physical and mental health challenges," says Curtin University epidemiologist Rosa Alati.

Sadly, people with ADHD are three times more likely than the general population to take their own life.

Like many others, I was diagnosed with anxiety, and later depression, as my efforts to seek professional help never quite seemed to provide more than a temporary fix.

The most problematic manifestation for me in recent years has been chronic insomnia, which affects close to half of adult ADHDers. And once sleep goes, every other symptom is of course exacerbated.

"Several factors contribute to the startling fact that a vast majority of adults are not receiving the appropriate treatment, including limited attention, limited access to specialized care, diagnostic challenges, and variations in treatment options," explains Curtin University psychiatrist and epidemiologist Getinet Ayano.

Even in Australia – a country that prides itself for having one of the best medical systems in the world – I experienced over a year's wait time for an appointment.

After all the considerable effort it took to get a medical diagnosis, part of me still doesn't quite believe it. Possibly because many of us have grown up thinking ADHD is just the hyperactive child incarnation, and internalized stigmatization of the symptoms.

No, I can not for the life of me explain why I can't remember to simply close the cabinets in the kitchen, and believe me, by the nth case of pantry moths attacking my food, I'm more frustrated over it than anyone else!

"ADHD is typically associated with children but can affect any age group," says Ayano.

There are actually several ways this poorly named neurodevelopmental difference can present. Ayano and team's review found most adults, like me, have the inattentive type. This is followed by the better known hyperactive form and a type that presents neither one or the other set of symptoms more often (combined).

The official diagnostic tools are based on the hyperactive presentation in children, which is why so many of us were missed earlier in our lives.

This is no small issue – not receiving treatment for ADHD in childhood is one of several factors that contribute to the likelihood of ADHD persisting into adulthood – as the authors describe in their paper.

Research shows that current treatments, though unlikely to alleviate all symptoms, improve long-term outcomes for people with ADHD.

My hyperactivity manifests more as internalized anxiety rather than anything physical. What's more, having inattentive ADHD doesn't mean I usually can't pay attention. On the contrary, the reason I can write and did well at school is my ability to hyperfocus on things that interest me, to the point of forgetting time exists and that I am a human who still needs to eat and drink.

The much maligned medications, which are still lacking in long-term efficacy and safety data, as well as therapy that actually accounts for my brain differences are helping immensely. I haven't slept this well in years!

The prevalence of ADHD does not match health resources it receives compared to similarly prevalent conditions, Ayano and team point out. They caution however, that their conclusions are still just an estimate as not all the articles they used in their review were clear on their methods.

However, hopefully their work will promote a greater understanding so that more of us can receive the help we need sooner.

"[The review] has not only shed light on the significant prevalence of ADHD among adults but also shows the dire need for greater awareness, diagnosis, and management of this condition in adulthood," concludes Ayano.

Their research was published in Psychiatry Research.

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