In the early 1900s when drug and alcohol addictions were first studied, they were thought to be simply a result of moral failure and a lack of willpower. Today, many scientific studies have brought about a new train of thought. Most organizations that deal with addictions now acknowledge that there are many more factors that can fuel an addiction. According to NIDA, the National Institute of Drug Abuse in America, addiction is a disease that affects behavior as well as the brain. There are both environmental and biological factors that result in the progression of the disease. Addiction is also a complex disease that requires a thorough understanding in order for it to be properly treated.