A loud snap made them all jump. Professor Lupin was breaking an enormous slab of chocolate into pieces.

‘Here,’ he said to Harry, handing him a particularly large piece. ‘Eat it. It’ll help.’

Prisoner of Azkaban - page 67 - UK Hardcover

Throughout the Harry Potter series, chocolate is used as the main treatment for contact with a Dementor, which we know is an analogy for depression.

Is there any scientific basis for JK Rowling using chocolate as a medical and psychological treatment in the HP series?