It's not just serotonin either-most neurotransmitters can cause anxiety or anxiety like symptoms, and in some cases an over-abundance of a chemical can lead to anxiety. So it does appear that you can develop it without experiencing a stressful life.
Howard Heinzl (1918 - 1989) With regard to blue American Staffordshire Terriers, any breeder that believes that a blue American Staffordshire Terrier is some how more valuable than the other recognized colours, is not only deceiving themselves, but they are also deceiving their customers.
Boxer (dog) For other uses, see Boxer (disambiguation). The Boxer is a medium-sized, short-haired breed of dog, developed in Germany. The coat is smooth and tight-fitting; colours are fawn or brindled, with or without white markings, and white.