Attention deficit hyperactivity disorder was first described in 1798 by Sir Alexander Crichton, a Scottish physician.

His work mentioned that the individuals he studied found it difficult to concentrate on a subject for a sustained period of time, that they were easily distracted or affected by sensory stimuli like heat, light or even a dog barking, which could bring on what he described as “the fidgets”.

The paradoxical effect of the stimulant Benzedrine was serendipitously discovered in 1937 by Charles Bradley, an American doctor experimenting with pneumoencephalograms on children identified with behavioural problems at Emma Pendleton Bradley Home, a children’s home in Rhode Island where he served as director.

But despite this long history, it was not until 1980 that the condition appeared in the second edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-II). It was called attention deficit disorder (ADD).