Washington: Addiction is more than mere substance abuse and could hold signs of a diseased brain, according to a new definition furnished by the American Society of Addiction Medicine (ASAM).

This new definition highlights addiction as a chronic brain disorder, not a problem involving too much alcohol, drugs, gambling or sex.

"Many behaviours driven by addiction are real problems and sometimes criminal acts," said Michael Miller, past president of ASAM who oversaw the development of the new definition. "But the disease is about brains, not drugs."

The new definition results from a four-year process involving more than 80 experts, including top addiction authorities, clinicians and leading neuroscience researchers from across the country.

Two decades of advancement in neurosciences convinced ASAM that addiction needed to be redefined by what is going on in the brain, according to an ASAM statement.

"Simply put, addiction is not a choice," ASAM committee chairman Raju Hajela said. "Addictive behaviors are a manifestation of the disease, not a cause."