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.
Description: The Miniature Boxer is a medium cross breed known for being affectionate, alert, friendly, gentle, intelligent, loving, loyal, playful, protective, and social. It is the cross of the Boxer and Boston Terrier. The most common colors for Miniature Boxers are black, brown, silver, and white. To keep it healthy, it will need to get exercise regularly. The Miniature Boxer commonly participates in guarding.