To quote Natasha Campbell-McBride

“Gut and Psychology Syndrome (GAP Syndrome or GAPS) is a condition, which establishes a connection between the functions of the digestive system and the brain. This term was created by Dr Natasha Campbell-McBride, MD, MMedSci (neurology), MMedSci (human nutrition) in 2004 after working with hundreds of children and adults with neurological and psychiatric conditions, such as autistic spectrum disorders, attention deficit hyperactivity disorder (ADHD/ADD), schizophrenia, dyslexia, dyspraxia, depression, obsessive –compulsive disorder, bi-polar disorder and other neuro-psychological and psychiatric problems. “