It takes an average of three-and-a-half years for typical dementia symptoms to lead to a diagnosis, a new report finds.

Diagnosis often comes even later for early-onset dementias.

Speeding up the process is important, because “timely diagnosis can improve access to treatments and for some people prolong the time living with mild dementia before symptoms worsen,” explained study lead author Vasiliki Orgeta.  She’s a professor of psychiatry at University College London in the U.K.

Her study is the first large-scale effort to calculate the lag between symptom onset and dementia diagnosis, the report’s authors said.

The study is what’s known as a meta-analysis: Data was pooled from 13 separate studies on the issue conducted in Europe, the United States, Australia and China. In total, the data involved more than 30,000 participants.

In a UCL news release, Orgeta noted that the “timely diagnosis of dementia remains a major global challenge, shaped by a complex set of factors, and specific health care strategies are urgently needed to improve it." 

She noted that certain studies suggest that only 50%-65% of cases "are ever diagnosed in high-income countries, with many countries having even lower diagnostic rates.”

The advent of medications that might slow the progress of Alzheimer’s disease (if given during the dementia’s early stages) makes early diagnosis more important than ever. 

But the new report found that, overall, it takes an average of three-and-a-half years after symptoms first appear for a patient to be properly diagnosed with dementia. 

That lag stretched to just over four years when the person was younger and experiencing early-onset dementia, the researchers said.

Younger age, as well having a form of illness known as frontotemporal dementia, were each linked to a longer time to diagnosis, Orgeta’s team said.

One of the studies also found that Black patients faced longer wait times to a dementia diagnosis. 

Why are patients waiting so long to have their dementia spotted and treated?

“Symptoms of dementia are often mistaken for normal aging, while fear, stigma and low public awareness can discourage people from seeking help,” said study co-author Phuong Leung, also of the UCL division of psychiatry. 

Other factors might include inefficient doctor referral systems when dementia is suspected, language barriers between patient and doctor, and under-staffed memory clinics, the research team said.

“To speed up dementia diagnosis, we need action on multiple fronts, “ Orgeta said. 

“Public awareness campaigns can help improve understanding of early symptoms and reduce stigma, encouraging people to seek help sooner," she continued. "Clinician training is critical to improve early recognition and referral, along with access to early intervention and individualized support so that people with dementia and their families can get the help they need.”

The report was published July 27 in the International Journal of Geriatric Psychiatry.