Some of these reports have come from the manufacturer of the drug, Pfizer, and others from the media and the internet, the regulator said.
There have also been reports of drowsiness, to the point of affecting the ability to drive, associated with the use of Champix.
A Pfizer UK spokesperson said that there is no scientific evidence establishing a causal relationship between varenicline and the post-marketing report events, and the role of Champix, marketed as Chantix in the US, is still unknown.
The agency has now asked Pfizer for any additional cases of side-effects that it is aware of and is currently reviewing the data.
The FDA recommends that GPs monitor patients taking Champix for behaviour and mood changes.
The Pfizer spokesperson said it was too early to speculate on any potential impact the review would have on the marketing of Champix in the UK but said the pharmaceutical manufacturer was in close contact with the European Medicines Evaluation Agency (EMEA) regarding the FDA communication.
'Pfizer is assessing the potential impact on the European product information and will continue to collaborate with the EMEA on any further developments,' said Pfizer in a statement.
Champix was licensed by the European Medicines Agency (EMA) in September 2006 and was made available on the NHS.
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