Residents across Amsterdam have reported unusual behaviour from friends and family members, leaving many confused and concerned.

Described as acting “like an opposite version of themselves,” those affected display sudden and uncharacteristic changes in personality and habits.“I don’t recognise my brother anymore,” said local resident Marieke Jansen. “He’s always been quiet and reserved, but now he’s loud, constantly making jokes, and doesn’t seem like the same person at all.

”The phenomenon, which has been observed over the past few days, is spreading throughout various neighbourhoods. Some have noted that it’s not just personality shifts but also a reversal of long-standing preferences and behaviours.

“My best friend always looks things up on their phone when someone asks a question, but lately they just shrug as if they don't care,” explained Johan De Vries. “It's really weird. Like people are mirroring who they really are.”

Authorities are yet to identify a clear cause for the sudden changes. Medical experts have ruled out any known illness, and there’s no consensus on what could be behind the strange behaviour.

In a statement made by the municipality of Amsterdam, mayor Femke Halsema provided words of caution, stating, "If you notice any concerning changes in behaviour among your loved ones, we encourage you to reach out to healthcare professionals. Additionally, please continue to report any unusual incidents to local authorities so that we can continue to monitor the situation closely."

For now, Amsterdam residents are left wondering what could be transforming their loved ones into strangers.

Residents across Amsterdam have reported unusual behaviour from friends and family members, leaving many confused and concerned.

Described as acting “like an opposite version of themselves,” those affected display sudden and uncharacteristic changes in personality and habits.“I don’t recognise my brother anymore,” said local resident Marieke Jansen. “He’s always been quiet and reserved, but now he’s loud, constantly making jokes, and doesn’t seem like the same person at all.

”The phenomenon, which has been observed over the past few days, is spreading throughout various neighbourhoods. Some have noted that it’s not just personality shifts but also a reversal of long-standing preferences and behaviours.

“My best friend always looks things up on their phone when someone asks a question, but lately they just shrug as if they don't care,” explained Johan De Vries. “It's really weird. Like people are mirroring who they really are.”

Authorities are yet to identify a clear cause for the sudden changes. Medical experts have ruled out any known illness, and there’s no consensus on what could be behind the strange behaviour.

In a statement made by the municipality of Amsterdam, mayor Femke Halsema provided words of caution, stating, "If you notice any concerning changes in behaviour among your loved ones, we encourage you to reach out to healthcare professionals. Additionally, please continue to report any unusual incidents to local authorities so that we can continue to monitor the situation closely."

For now, Amsterdam residents are left wondering what could be transforming their loved ones into strangers.