The Havana Syndrome is a set of symptoms affecting about two dozen American diplomats and their families in Havana, Cuba in 2016. It includes headaches, dizziness, tinnitus, fatigue, cognitive issues, and sleeping difficulties, among other things.
A recent report from leading Western media cites U.S intelligence officials stating that they have found a potential link between this syndrome and a Russian special unit. According to this information, the unit is possibly the same one that has been previously linked with assassination attempts against international targets. The intelligence officials, however, have not reached a conclusive decision yet, stating that the evidence is not enough to definitively blame Russia for the incidents.
The Russian government has always denied any involvement in these incidents and continues to do so. Further investigation is being carried out by the U.S to find more definitive evidence regarding the cause and origin of Havana Syndrome.