SSRI antidepressants have been linked to a number of adverse effects. A recent study presents evidence that a new condition may need to be added to that list: visual snow syndrome.
Visual snow (VS), persistently seeing tiny flickering dots, was first described in medical literature from 1944 as a negative effect of heart medication. Doctors mostly understood VS as an anxious reaction to normal visual disturbances or a migraine related aura. In 1995, it was described in the medical literature for the first time as a symptom of migraines that could last for months or even years, separate from the more common auras. The term “visual snow” was coined in 2005, in another paper linking the condition to migraines.
A 2014 study presented evidence that visual snow was a neurological issue and could occur in people that did not have migraines, establishing it as a separate and unique condition. This research also laid out the diagnostic criteria still used today to diagnose visual snow syndrome (VSS), which includes:
- Constant visual snow for three months or longer and at least two of the following symptoms
- Afterimages or the appearance of trailing objects
- Excessive “floaters” or visual disturbances that seem to come from inside the eye
- Light sensitivity
- Impaired or reduced night vision
The overall prevalence of VS has been estimated to be between 3% to 7%, with VSS affecting 2.2%. There are treatments that may lessen some of the symptoms for some service users, but VSS can be lifelong.
While the causes of VS and VSS are debated among experts, past research has pointed to SSRIs as one possible cause. A 2020 study hypothesized that increased levels of serotonin led to misfiring of receptors involved in filtering out visual information, causing the perception of visual noise or snow. A 2023 paper pointed to the role of SSRIs in rewiring the thalamus. This part of the brain acts as a kind of filter, letting only some sensory information through into consciousness. The authors suggested SSRIs could weaken the inhibitory signals, which rely on serotonin. This could result in a failure to filter out “neural noise,” leading to visual snow and the other symptoms associated with VSS.
People that experience VSS often report that it can have significant effects on daily life.
“Day to day life becomes significantly more challenging. Your coping system can feel like it is stuck in a weaker mode, where things most people brush off take more effort to handle,” writes VSS sufferer Chris Karp in an interview on Reddit. “Reading is harder, astigmatism is worse, screens can be painful, night vision is awful, and even something as simple as looking at the stars can feel like it has been taken away.”
A recent study published in the International Journal of Risk & Safety in Medicine adds new evidence linking SSRIs to VSS.
The current work, led by Hannaa Bobat of St Mary’s Hospital and David Healy from Data Based Medicine in the UK, finds a strong possibility that SSRIs are linked to VS. This research also presents evidence that VSS can start while taking SSRIs, after reducing the dose, and after discontinuation. Most patients continued to experience VS or VSS after quitting SSRIs.
“The starting dose for most SSRIs is a toxic dose – a dose that occupies pretty well all uptake sites and people stay on these meds for decades. It is not surprising that this causes damage,” Said Healy in an interview by email. “The VS linked to SSRIs is likely much more intense than previous VS and is not episodic as it may be in migraine. It leaves people feeling they are going mad … If SSRIs help you, the best advice is take them in a low dose. Five mg Prozac is just as effective as 20 mg. And stop when you can.”
Methodology
The goal of the current work was to examine the relationship between SSRIs, VS, and VSS. The authors used data from the independent drug safety website RxISK.org. Two of the authors (David Healy and Dee Mangin) were among the founders of RxISK.org in 2012. This website allows service users to report adverse events related to prescription drugs. Respondents answer a questionnaire on age, gender, country of origin, drug consumption, medical history, relevant health information, impacts on quality of life, and clinical details of the adverse event.
RxISK.org uses three methods, Koch’s postulates, the Bradford-Hill criteria, and the Naranjo algorithm for cause and effect, to calculate the likelihood that the reported drug caused the adverse event. A score of five or higher means a possible link, with scores above nine indicating a strong likelihood that the drug caused the incident.
The authors searched data collected by RxISK.org between June 17, 2012 and April 4, 2024 on adverse events where SSRIs, SNRIs, and serotonin inhibiting tricyclic antidepressants were suspected of causing VS. Reports were excluded when VS was not the primary reason for reporting, other factors were a more likely cause of the VS, the description of VS was inaccurate or unconvincing, the timeline was unclear, they were duplicates of prior reports, or they were about worsening VS.
Results
In total, 24 records met the criteria for inclusion in the current work. The service users reporting adverse events were between 18 to 56 years years old. Sixteen were male and eight female. Reports came from the US (10), UK (7), India (2), Canada, France, Israel, Poland, and Turkey. All these cases involved VS with 10 (42%) meeting the criteria for VSS. Sixteen reports (63%) involved at least one additional symptom consistent with VSS. Further symptoms not included in VSS diagnosis were reported in 14 cases (58%). This included blurred vision (7), double vision (2), dry eyes (4), eye pain (3), halos (5), and metamorphopsia (1). One service user reported that they had cataract, and another retinopathy, in addition to VS.
“I have very severe VSS with many symptoms. The physical symptoms are the worst.” Said Marika in an interview on Reddit. “In addition to strong afterimages, severe photophobia (my eyes hurt even when I turn on a small night lamp at night), visual snow, floaters, halos, glare, starbursts, and sound sensitivity, I also have very dry eyes—no drops or ointments help. My eyes burn nonstop.”
Ten serotonin affecting antidepressants were reported as possible causes for VS and VSS. Sertraline was the most commonly reported (8 cases), followed by escitalopram (5). Citalopram, fluoxetine, and venlafaxine were reported in two cases each while amitriptyline, duloxetine, paroxetine, vilazodone and vortioxetine were each suspected in one case. Treatment duration ranged from one dose to 18 years.
RxISK scores ranged between two to 17 with an average of 9.5 across all reports, indicating a strong link between these drugs and VS. Most reports (13, 54%) scored a nine or above, with nine cases (38%) scoring between five to eight.
Most service users reported that VS symptoms began while taking an antidepressant (14 cases, 58%). Six cases (25%) started after dose reduction, and four (17%) after discontinuing antidepressants. VS persisted for 22 service users after quitting the drug suspected of causing the symptoms. A single person reported improved (but not resolved) symptoms after quitting antidepressants. Four service users indicated worsening symptoms and 17 reported persistent VS after discontinuation. Eleven people reported that their VS symptoms had lasted for at least one year after stopping antidepressants. The longest reported persisting symptoms after discontinuation was four years.
The authors write:
“Our data suggest that SRIs may trigger VS as well as a range of visual disturbances consistent with VSS that generally fail to resolve upon discontinuation of treatment and can even worsen or in some cases emerge upon stopping the drug. Further research is called for to better understand mechanisms and identify risk factors.”
While the prevalence and causal pathways of possible SSRI induced VS is unknown, Healy notes “RxISK has more reports of people with visual problems on these meds than people having suicidality triggered by these meds.”
Half of service users (12) that reported VS as a result of antidepressants said their symptoms were severe enough to alter their daily lives, with 11 (46%) saying they saw changes in their social activity, friendships, or relationships as a consequence of VS. Fifteen (63%) also said they had difficulties at work due to VS. Several members of a Reddit forum dedicated to research on visual snow and support for VSS sufferers described their daily experiences in short interviews with Mad in America.
Marika reports that VSS has a strong impact on daily life.
“It’s impossible to live normally. I’ve had VSS for 2 years, and since then I haven’t worked … I don’t know how I’ll cope with such a horrible condition. The light sensitivity is so intense that I feel like I’m in another dimension. It can’t be explained. Everything is so sharp that it makes me want to vomit. I almost forgot to mention that on a daily basis I also struggle with nausea. There are days when it’s not there, but there are more days when the nausea is present. Chronic fatigue does not go away. I can sleep 10–12 hours and still yawn all the time. I have no strength for anything.”
Another member of the VS Reddit forum, L. M. , says that life is permanently changed for many VS sufferers with little sympathy from those around them.
“While many learn to live with it, those who got it later in life are acutely aware that their lives will never be the same. How they see the world and themselves – and others – changes permanently and there is no way to go back. And no sympathy or acknowledgment from doctors or friends because how can you explain that you aren’t crazy but also my vision has changed.”
Limitations
The authors acknowledge three limitations to the current work. The retrospective design means that this data can only speak to links between SSRIs and VS. While they use several algorithms to calculate the probability that antidepressants caused VS, this data cannot definitively say that SSRIs caused these cases. The self report nature of RxISK.org reports means the data is susceptible to misremembering and misreporting. The sample size was also small, limiting genralizability to larger populations of SSRI users and VS sufferers.
“The other point that has come to light in our recent efforts to get the latest VSS paper into print is it is becoming harder and harder to get peer reviewed journals to take articles that outline adverse effects,” Healy reported by email. “Submissions get turned down without review.”
Beyond Visual Symptoms
Several people that experience VSS reported that it goes beyond the visual symptoms. These ripple effects involved attention, emotion, cognitive difficulties, and anxiety related to the possibility of worsening VSS symptoms.
“VSS changes your perception as a whole. It is not just a handful of symptoms,” said Karp. “The visual symptoms are the core, but they can also spill into attention, emotion, and the overall way you perceive the world.”
In an interview on Reddit, Elliot linked VSS to intense brain fog and symptoms of Depersonalization-Derealization Disorder.
“My visual symptoms aren’t the worst part of my VSS … The symptoms that make life unliveable for me are the unremitting DPDR and brain fog. It’s like I’ve lost the most fundamental part of my human experience in a way I can’t even properly describe. It’s like my underlying rate of perception has been quantised and slowed to a crawl, my every thought like I’m trudging through molasses. It’s like I now live on a significantly lower level of conscious experience, my highs far less high, my lows far less low. Everything in my life with VSS is trivialized by the life I used to live.”
L.M. reports developing a fear around illnesses and taking medications after Benadryl temporarily increased their VSS symptoms.
“SSRIs can make this worse. So can antibiotics, steroids, literally anything that others find easy to take and innocuous OTC drugs or mental health treatments start to feel like Russian roulette. After this all started for me, I realized Benadryl makes it worse. I took it, feared I made it permanently worse, and breathed a sigh of relief when I found the effect was temporary. I am now genuinely scared of illnesses in a new way – not because of the illness, but because of the possibility of any one of the many incurable and sometimes debilitating symptoms getting worse.”
Dismissed as a “Mental” Issue
The authors of the current work, as well as lived experience experts, have pointed to a dismissive attitude towards VSS by some ophthalmologists and neurologists.
“The majority of ophthalmologists consider VSS a ‘functional neurological disorder’ – the main aim being to rule out a brain tumour or other life or sight-threatening disease. Once that’s done, it’s time to reassure the patient there is nothing wrong or refer them for counselling,” said Bobat.
Healy added that this dismissive attitude is likely worse for people that have taken SSRIs in the past.
“When ophthalmologists look in the eye, they see nothing wrong and figure the complaints of people convinced there is something wrong are mental/brain problems – it is easier to think this when the history shows they are on or have been on SSRIs. For eye docs, its clearly even more likely to be ‘mental’ if you are no longer on the SSRI. They refer you to mental health and put you on an SSRI – for anxiety.”
Karp confirms Bobat and Healy’s reports of dismissive physicians, emphasizing the frustration of being misunderstood and the possible harm of incorrect treatment.
“Doctors often minimize it or write it off as anxiety. What makes this even more frustrating is that some common anxiety medications, including SSRIs, can worsen visual symptoms for many. So you are not only struggling to be understood, you can also end up being harmed by prescriptions that do not match what is happening.”
The Link Between VSS Symptoms and Anxiety
While some physicians may be too quick to dismiss VSS as simple anxiety, research has found a connection between lifetime and severe anxiety and VSS. The Visual Snow Initiative (VSI), a VSS patient advocacy group, describes anxiety and visual snow as a vicious cycle. Essentially, anxiety causes hypervigilance, a state in which sensory input becomes more obvious. Hypervigilance leads to more focus on the VSS symptoms, which increases anxiety.
“Insofar as the described symptoms of VSS are continuous with normal perception, it is sometimes very difficult to determine what is pathological or not. As is also the case with HPPD, the designation of self-reported phenomena that increase with anxiety as ‘symptoms’ of a brain-based syndrome with little-to-no direct treatments may create the disorder,” Journalist and Hallucinogen Persisting Perception Disorder (HPPD) expert Ed Prideaux wrote in an email interview. Prideaux links anxiety and obsessional disorders to some cases of visual disturbances like those seen in HPPD and VSS. “Once those go down, the intensity of symptoms often reduces.”
VSS sufferer D. P. reports noticing a similar connection between health related anxiety, Obsessive-Compulsive Disorder, and VSS.
“The biggest problem with the onset of VSS for many is the accompanying onset of mental distress symptoms, some of which (such as derealisation and depersonalisation) are regarded as linked to the condition itself. On VSS support subs you’ll see a high number of people with health anxiety, OCD, and depression.”
Prideaux points to an article that argues against the disease framing of VSS as a “controversial but interesting critique of the VSS concept.” This piece argues that the evidence for VSS as a neurological disorder is weak. The author contends that VSS is not pathological, but rather “entirely benign and nothing to worry about.” In this context, the suffering reported by service users would be mostly due to anxiety and obsession focused on these visual disturbances.
Prideaux also worries about the possibility of some normal visual disturbances being framed as pathological. He observes that the VSI 4 kids platform has “a ‘Brainiac’ chatbot offering ‘advice’ for children and suggesting that they may want to visit a doctor if they experience any static, even at night time or on blank surfaces, which are entirely normal.”
He points to quotes from children on the VSI website that may reveal a pathologizing of relatively normal visual disturbances. One child reported realizing they had VS after seeing the symptoms talked about on social media. Another reported going to ophthalmologists and neurologists after noticing worsening VS “on plain white walls, in the dark, or when I close my eyes.” Prideaux believes “This raises red flags that VSS is subject to a certain ‘cyberchondria’,” compounding concerns after exposure to VSS related information online.
While Prideaux says VSS symptoms may be exacerbated by anxiety, and worries some normal visual experiences may be framed as pathological, he also maintains that VSS is something of a mystery and cautions against framing it as predominantly psychological.
SSRIs and VSS Support Forums
While many people from VSS support forums view SSRIs suspiciously, some report improvements while taking them.
“My VSS onset as a teen was accompanied by significant mental distress, that left untreated lead to long term depression and anxiety. I eventually tried SSRIs almost 2 decades later, and found I tolerated them well. They helped to alleviate mood issues,” writes D. P. in a Reddit support group for VS.
Others are steadfast in their belief that SSRIs caused their VSS. “Of course SSRIs cause VSS. I am 200% sure of that,” reports Marika. “I dream of treatment, real treatment, like brain neuromodulation or medications. I pray to God for this.”
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Bobat, H., Healy, D., Mangin, D., & Lochhead, J. (2025). Serotonin reuptake inhibiting antidepressants: A trigger for visual snow syndrome? International Journal of Risk & Safety in Medicine. (Link)
The post Visual Snow Syndrome: Can SSRIs Literally Change How You See the World? appeared first on Mad In America.
IPAK-EDU is grateful to Mad In America as this piece was originally published there and is included in this news feed with mutual agreement. Read More
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