A researcher who has examined claims surrounding so-called “Havana syndrome” has said he conducted a self-experiment involving a device he believed could replicate aspects of the reported symptoms, underscoring ongoing debate over the origins of the mysterious condition.

The scientist, who has publicly expressed scepticism about the existence of a covert energy weapon responsible for the incidents, said he exposed himself to controlled electromagnetic emissions as part of an attempt to test whether such signals could plausibly produce the neurological complaints described by diplomats and intelligence personnel.

“Havana syndrome” emerged in 2016 after U.S. and Canadian officials stationed in Cuba reported headaches, dizziness, cognitive difficulties and auditory disturbances.

Subsequent reports surfaced in other countries, prompting investigations by multiple governments.

While some officials initially raised the possibility of a directed-energy device, later assessments have varied in their conclusions.

According to the researcher, his self-test was designed to examine whether electromagnetic frequencies within a certain range could trigger acute symptoms under laboratory conditions.

He said he experienced no lasting effects and argued that the findings reinforced his view that environmental, psychological or medical explanations may be more consistent with the available evidence.

U.S. intelligence assessments released in recent years have suggested that it is unlikely a foreign adversary deployed a weapon in most reported cases, though investigations remain complex and some individuals continue to report persistent symptoms.

Other scientists have proposed hypotheses ranging from microwave exposure to mass psychogenic illness, but no single cause has been conclusively established.

The researcher’s account has drawn both criticism and support within the scientific community.

Some experts caution that individual self-experimentation cannot definitively resolve questions about exposure mechanisms, while others see it as part of broader efforts to scrutinise extraordinary claims through empirical testing.

As governments continue to review cases and provide medical support to affected personnel, the episode illustrates the difficulty of investigating health incidents that intersect with geopolitics, intelligence concerns and emerging technologies.

The debate over “Havana syndrome” remains unsettled, with competing interpretations persisting in the absence of definitive physical evidence.