The 17-year-old is sharing her story to coincide with FND Awareness Day on Saturday.

FND [functional neurological disorder] is a chronic illness that affects how the nervous system and body send and receive signals.

"I didn't get diagnosed until I became suddenly paralysed in June 2021, after months of unknown illness," Charlotte said.

"My parents had to call an ambulance after my mum found me passed out in my room and not responding. After a while, I was talking but completely unable to move or even open my eyes."

Paramedics took Charlotte to the emergency department.

"They looked at my medical file and, because I had previous mental health issues, they put it down to that without even trying to find answers for us," she said.

"They asked Mum to take me home while I was still completely paralysed. Mum fought to get me admitted and I stayed in the children's ward for three days, but the paediatric doctor would not agree to take my case."

She was transferred to another hospital, where a neurologist saw her and "immediately suggested the diagnosis of functional neurological disorder, after reading my file and running several tests".

Charlotte spent the next seven weeks in hospital receiving treatment to retrain her brain how to walk. She spent two months in a wheelchair and an additional two months using a walking frame.

FND patients can often experience frustration in the medical system, due to their symptoms being dismissed or attributed only to psychological factors.

FND Australia describes the condition as "a disabling and distressing neurological disorder".

The organisation's founder Dr Katherine Gill said research had shown "there are actual changes in the brain of people with FND".

Dr Gill said these changes involve "aberrant connectivity between the limbic system and motor system".

"In a healthy individual, you'd have a stress response where you get upset or angry.

"In a person with FND, because the limbic and motor system are hyper-connected, an emotional stress response can mean they can't walk or talk."

Dr Adith Mohan, a neuropsychiatrist and research fellow with UNSW Sydney's Centre for Healthy Brain Ageing, said FND is a "neuropsychiatric disorder where the mind-body interface is affected".

"As such, it is both a physical health issue as well as a psychological one and treatment must address both," Dr Mohan said.

While the exact causes of FND were not clear, "various psychological, social and physical health factors are known to be strongly associated and are considered relevant in its causation".

"People with FND carry high levels of distress and disability."

Charlotte agreed that psychological factors "can definitely influence the severity or impacts of symptoms".

"Stress makes it harder for anyone to function, so when brain functions are already facing problems it can make symptoms worse," she said.

"It is vital that more research goes into this condition."

Charlotte said she was "turned away from emergency many times with no answers" for years prior to her diagnosis.

"I had traumatising experiences with nurses and doctors. Nurses would often leave me unattended and unable to move, go to the bathroom, get food or transfer to my wheelchair."

Dr Gill said people with the condition are often "treated appallingly in care".

"In general, people are struggling to access care. We're getting around 15 inquiries a day from people newly diagnosed, in crisis and not knowing where to turn or what to do."

Dr Gill said the nature of the condition created situations in which those affected can "walk in the morning, but can't walk and are wheelchair-bound when they're fatigued later in the day".

"The public don't understand that. It leads to kids being bullied and people not being understood, heard or believed. It's really challenging to live with."

She said those with the condition can face "stigma and discrimination in the community, health services, workplaces and schools".

Charlotte said the condition "can affect any body function".

"The biggest impact FND has on my life currently is very high levels of fatigue," she said.

"This often means I have to choose between resting or seeing my friends, working or studying, playing sport or attending a full week of school.

"I sometimes find myself falling behind socially, as during school almost all my energy is used trying to focus and learn. When I get home, I have nothing left and have to rest.

"FND also adds an extra layer of anxiety to my life, as it is completely unpredictable."

She missed more than half of year 10 and continued to have numerous sick days in years 11 and 12.

She manages her condition with physio, psychology, psychiatry, occupational therapy and medication.

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