Since publicly disclosing her multiple sclerosis (MS) diagnosis in 2018, Selma Blair has inspired many people living with the disease. Her candid accounts of its profound effects on her health have earned widespread admiration.
This weekend, however, the 54-year-old actress drew attention for an entirely different reason.
Blair was arrested Sunday after an alleged confrontation with cabin crew on a Delta flight. She is accused of assaulting flight attendants and trying to open an aircraft door while the plane was airborne.
Her attorneys have said she was experiencing a medical emergency after missing several doses of her medication.
But can abruptly stopping treatment cause such a dramatic change in behavior?
Some medications prescribed for MS can produce serious withdrawal effects if treatment is suddenly interrupted, including confusion, hallucinations and, in severe cases, psychosis.
It is not known which medications Blair was taking, or whether any of them contributed to the incident.
The Daily Mail has examined the treatments Blair has received, along with the lesser-known dangers linked to abruptly stopping certain medications used to manage MS.
Blair is pictured at The Beverly Hills Hotel during an event on September 23
Blair’s long battle with multiple sclerosis
Blair was 46 when doctors diagnosed her with multiple sclerosis, an incurable neurological disorder that affects nearly one million Americans.
MS occurs when the immune system mistakenly attacks the protective coating surrounding nerves in the brain and spinal cord. The resulting damage can interfere with communication between the brain and the rest of the body.
Symptoms vary widely and may include muscle weakness, difficulty walking, extreme fatigue, vision problems, and trouble with memory and concentration.
Blair has said she believes the disease affected her for decades before it was identified in 2018. She discussed her experience at a Women’s Health Lab event last year.
At the event, she said bladder problems, impaired vision and mobility issues had troubled her since she was seven years old.
Doctors initially explored whether she had cancer, but after those tests came back negative, her symptoms were reportedly dismissed.
“It took me 30 years to get an MRI,” she said.
She also remembered waking during the night as a child and experiencing uncontrollable bouts of laughter, followed by periods of sobbing.
Blair now suspects those episodes could have been symptoms of childhood-onset MS, a rare form of the condition believed to represent approximately 3 to 5 percent of cases.
By the time she was diagnosed, Blair had spent years dealing with unexplained symptoms such as muscle spasms, severe exhaustion and difficulty walking. She has previously acknowledged using alcohol to cope.
Her experience was documented in the 2021 film Introducing, Selma Blair, which followed the actress through intensive treatment.
The film showed her struggling to walk without a cane, battling overwhelming fatigue and confronting the possibility that the treatment itself could prove life-threatening.
‘I was told to make plans for dying. Not because I have MS, but because I’m fighting MS,’ she said in the trailer.
In 2019, Blair underwent a hematopoietic stem cell transplant (HSCT), an intensive procedure involving chemotherapy to suppress the immune system before previously collected stem cells are returned to the bloodstream.
The aim is to rebuild the immune system so that it stops attacking the protective coating surrounding nerves.
Although the treatment can be highly effective in selected patients with active MS, it carries significant risks, including potentially life-threatening infections.
Blair has since spoken about the lasting physical toll of the disease.
In a 2023 interview with NBC’s Meet the Press, she revealed that she continued to experience pain every day, despite feeling that her health was gradually improving.
She also described suffering from dystonia, a neurological movement disorder that causes involuntary muscle contractions and can affect speech.
‘I have dystonia, also, that really doesn’t always flare up for entire conversations, but it’s almost like someone with a stutter, maybe, or a type of Tourette’s,’ she said.
Blair has also revealed that she has Ehlers-Danlos syndrome, a connective tissue disorder that can cause joint instability and chronic pain.
In April this year, she said her MS had been in remission since 2021.
But while remission means there is no apparent new inflammatory disease activity, it does not necessarily mean freedom from symptoms. Many patients continue to experience pain, fatigue and mobility problems caused by earlier damage to the nervous system.
Could stopping MS medication trigger a breakdown?
Over the years, Blair has spoken about trying a range of treatments to control her illness.
As well as chemotherapy and a stem cell transplant, she revealed in 2024 that she was receiving intravenous immunoglobulin (IVIG), an infusion containing antibodies collected from healthy blood donors.
Although used to treat certain immune and neurological disorders, IVIG is not a standard disease-modifying treatment for MS.
She has also discussed trying ketamine, which is sometimes prescribed for severe depression or certain types of pain, and Botox injections, which can help relieve the muscle stiffness and spasms associated with neurological conditions.
Blair has previously been associated with Mavenclad, the brand name for cladribine, a drug that reduces the activity of immune cells involved in MS.
Unlike medicines taken daily, cladribine is administered in short treatment courses, with its effects lasting long after the tablets have been taken.
It is not known to cause an acute psychiatric withdrawal syndrome if treatment is interrupted.
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However, many people with MS are also prescribed drugs to manage symptoms such as nerve pain, muscle spasms and sleep disturbances.
And it is some of these medications that can cause particularly alarming reactions when suddenly stopped.
One is baclofen, a muscle relaxant commonly used to relieve spasticity – the painful stiffness and involuntary muscle contractions experienced by many MS patients.
It works by acting on GABA-B receptors in the nervous system, reducing excessive nerve signaling and helping muscles relax.
But after regular use, the body can become physically dependent on its effects.
If the drug is abruptly withdrawn, nerve activity can rebound, triggering anxiety, agitation, insomnia and a worsening of muscle spasms.
In severe cases, patients can develop hallucinations, confusion, delirium and seizures.
Some may become profoundly disorientated or behave in ways that are entirely out of character.
Withdrawal symptoms from oral baclofen can begin within hours to several days, often emerging within the first 24 to 72 hours.
The most dangerous reactions are associated with the sudden interruption of baclofen delivered through a pump directly into the fluid surrounding the spinal cord, although serious withdrawal can also occur in patients taking tablets.
Another drug sometimes prescribed for MS-related nerve pain is gabapentin.
It is used to relieve the burning, stabbing or electric-shock sensations caused by damage to the nervous system.
Suddenly stopping gabapentin after regular use can cause anxiety, agitation, sweating, insomnia and nausea.
More severe reactions, including confusion, hallucinations and psychotic symptoms, have also been reported, although these appear to be uncommon.
The risk is influenced by factors including the dose, how long the drug has been taken and whether a patient has developed physical dependence.
Meanwhile, some patients may be prescribed benzodiazepines, including diazepam, better known as Valium, or clonazepam, sold as Klonopin in the US.
These medicines are sometimes used to relieve muscle spasms, anxiety or sleep problems, although they are not generally recommended for long-term use because of the risk of dependence.
They work by enhancing the effects of GABA, a chemical messenger that helps calm activity in the brain.
When taken regularly, the nervous system adapts to their presence.
Stopping suddenly can therefore cause a rebound in brain activity, producing intense anxiety, panic attacks, tremors and insomnia.
In the most serious cases, withdrawal can trigger hallucinations, delirium, psychosis and potentially life-threatening seizures.
Symptoms may develop within a day or two with shorter-acting drugs, but can take several days to emerge with longer-acting medications.
Crucially, none of this establishes what happened to Blair.
There is no confirmation that she was taking baclofen, gabapentin or benzodiazepines at the time of the incident, and it would be wrong to assume that medication withdrawal explains her alleged behavior.
MS itself can also affect mental health, with depression and anxiety relatively common among patients.
More serious psychiatric disturbances, including mania and psychosis, are much rarer but have been reported, sometimes in association with inflammatory changes in the brain.
What patients need to know
Blair, pictured above in 2024, has been open about her MS diagnosis and the challenges she faces
Doctors warn that patients who take baclofen, gabapentin or benzodiazepines regularly should never stop them abruptly without medical advice.
Depending on the drug, dose and duration of treatment, stopping safely may require a gradual reduction over days, weeks or months.
For people who have been taking benzodiazepines for a prolonged period, this process can take considerably longer.
However, missing a single dose does not automatically cause withdrawal, and the risks vary significantly among medications.
Patients who forget a dose should follow the instructions provided with their prescription or seek advice from a pharmacist, rather than taking extra tablets to compensate.
The advice is different for disease-modifying MS treatments, which do not generally cause the same withdrawal reactions.
However, stopping some of these drugs can allow disease activity to return, occasionally with severe relapses, so treatment should not be interrupted without consulting a neurologist.
Sudden confusion, hallucinations, extreme agitation or seizures after stopping medication should always be treated as a medical emergency.
Such symptoms may be caused by withdrawal, but can also indicate an infection or another serious neurological problem requiring urgent assessment.
For patients and their families, the message is that medicines used to manage MS can carry risks not only while they are being taken, but also when treatment is unexpectedly interrupted.
The Daily Mail has contacted Blair’s representatives and lawyers for comment.