Do lab monkeys suffer from depression?

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Researchers insist there is no alternative if we are to find cures for Parkinson's Disease and other conditions and test vital new drugs. The Home Office takes into account the "severity" (others would say cruelty) of a proposed experiment before issuing a licence.

But until recently no one had given much thought to how the monkeys stand up to repeated experiments - some of them can be operated on as many as 10 times over a period of years - or the psychological impact of a lifetime in the laboratory.

Researchers say most monkeys, who have been bred and trained for laboratory work, do not put up a fight when experiments are conducted on them. Does that mean they have given their "consent"?

Do they find it a positive experience? Or is their passivity down to the fact that they are suffering from severe depression?

The article is here.