By ANDY BEAVEN, NEWS AND FEATURE WRITER and LUKE ANDREWS, U.S. SENIOR HEALTH CORRESPONDENT
Published: 12:27 BST, 11 August 2026 | Updated: 13:02 BST, 11 August 2026
Completely out of character, Jim Harwood found himself intensely stressed and angry about even the most trivial things.
Someone pushing a shopping cart in front of him at the grocery store or a minor error by a work colleague would trigger a harshly worded outburst which he would immediately regret.
At the same time, the razor-sharp focus and intense concentration he had always relied on as a computer programmer was starting to desert him. He struggled to keep his mind on the job, to remember names, to control his words and actions.
The 73-year-old says: 'I just didn't know what was happening to me. I had a level of irritability – of stress and anxiety – that I just couldn't explain.'
As the symptoms got worse, he considered any number of possibilities – from the onset of dementia to even mad cow disease. One thing he never imagined, however, was that his problems were caused by his thyroid.
Yet experts have told the Daily Mail that psychological and cognitive disturbances are an under-recognized and frequently overlooked symptom of hypothyroidism – a condition that affects nearly five percent of Americans ages 12 and older.
And they have called on doctors to consider thyroid tests in patients struggling with symptoms such as depression, anxiety, memory problems and difficulty concentrating – to establish whether an underactive thyroid could be to blame.
Completely out of character, Jim Harwood found himself intensely angry about trivial matters
Kristien Boelaert, professor of endocrinology at the University of Birmingham and a trustee of the British Thyroid Foundation, says: 'Hypothyroidism often goes undiagnosed. So if people go to their doctor with anxiety or depression – especially if they are showing any of the other more commonly recognized physical symptoms – then doctors should be prepared to suggest tests for thyroid function.'
So how can you know whether you have hypothyroidism? And how can it be treated?
First, it's important to explain what exactly the thyroid is. The thyroid gland is a small, butterfly-shaped organ found in the neck just in front of the voice box that produces crucial hormones needed to keep the body healthy.
In hypothyroidism, levels of these hormones are too low, which can lead to a wide range of physical symptoms including tiredness, weight gain, feeling cold, constipation, dry or thinning hair, muscle weakness, aches, a hoarse voice and slowed speech and movement.
However, because receptors for thyroid hormones are also found in the brain, research shows that hypothyroidism can even affect how people think and feel.
