Psychiatrymiddle twist
A 46-year-old accountant is brought in by his wife. Over five weeks he has become convinced that his neighbours are broadcasting his thoughts to the street, and for the past fortnight he has woken most mornings with a headache that eases by lunchtime. He has never seen a psychiatrist and takes no medicines. He is alert and fully oriented, there is no fever, no abnormal movement and no rigidity, and neurological examination including fundoscopy is normal. Full blood count, electrolytes, liver biochemistry, calcium, thyroid function and urine drug screen are all normal. Which one of the following investigations should be arranged next?