Phantom Scents???

I wasn't sure where to post this, sorry if this isn't a good place. Feel free to redirect me.

My Dx is Depression and Anxiety not Psychosis or Schizophrenia. That being said, I have had intermittent experiences of smelling phantom scents, namely cigarette smoke. This has been happening off and on for a few months, and it seems to happen for a few days to a week at a time when I'm stressed more than usual.

Looking it up on line is almost funny. Why does everything have to be a brain tumor? Should I be concerned?

I read somewhere that scent is strongly connected to memory, and I am afraid that I may be closer to remembering something I don't want to.

Thoughts on olfactory hallucinations welcome!

I get those a lot & for a few different reasons. Some of them are hallucinatory, but I also get them thanks to migraines & panic attacks. I have no idea why, as far as the third reason goes. I'm not sure whether the scent triggers the panic attack or the panic attack causes a phantom scent to be detected... I hope someone else has something more intelligent to add. Hopefully even an article? Regardless, hopefully this mystery subsides soon!

For me, panic/anxiety definitely applies!

Somewhere online I saw this associated with epilepsy too.

Thanks for responding! I wasn't sure if anyone would!

What scents are typical for you? For me it is always a cigarette smoke smell, like I just walked out of a bar or resteraunt --I have always been a non smoker too!

Cigarettes, gasoline, & paint fumes are most common for me. And once I got a really pretty floral scent, like jasmine. The cigarette one really freaks me out sometimes because no one here smokes & I get worried every time that something accidentally caught fire. Haha. Weird.

http://www.drweil.com/drw/u/QAA40068...-the-Time.html

I found this article and a couple more but they all say about the same thing

Well, depression is on the list of disorders in which you can have mild hallucinations! While I'm sure that's not totally comforting, it's highly unlikely that you have epilepsy or a tumour if you already have a disorder in which the phenomena is known to be present.

Hi Growly -

I am in the field of neurophysiology, and encounter this kind of thing on a regular basis. Olfactory hallucinations can be caused by a number of different assaults/injuries to the brain - specifically the olfactory tract, which is quite long. This can include what we call 'space occupying lesions' (tumors, benign and malignant, and other things like scar tissue, cysts, etc). It also includes head trauma, and even something going amiss with the blood supply system of the brain, especially migraines. Schizophrenia and Simple Partial Seizures in epilepsy are probably the most common causes.

The temporal lobe of the brain is responsible for a lot of sensory information. Temporal lobe epilepsies (TLE) have symptoms that can mimic psychiatric disorders, including hallucinations that are auditory, visual, olfactory, and gustatory (taste). Other symptoms can include sensations of sudden unexplained emotions of fear, anxiety, rage, and even elation, happiness, and laughing fits. Sensations of self are not uncommon, like depersonalization, derealization, deja vu, jamais vu, just about the whole gamut of hallucinatory experiences felt by those with schizophrenia.

With respect to olfactory hallucinations, there are some characteristics that are more typical if it's a result of a simple partial seizure. First, the odor is usually an almost indescribable obnoxious smell, along the lines of something putrid, chemical-smelling, sulfur, or something burning. Second, if it's a seizure, it is usually brief, lasting anywhere from a few seconds up to a few minutes (usually under two minutes). If the hallucination lasts longer, if not schizophrenia, it's usually a more permanent injury to the brain - like tumors, head trauma, blood supply issues, etc. Third, with seizures the smell is usually consistent - in that it won't smell like flowers one time, fruit another, and like burning rubber another time. If the smell varies, it's usually still pretty close. Seizure-provoked smells can be accompanied by q variety of other sensory symptoms, such as feeling like you're in a time warp, visual hallucinations, feeling like you're 'zoned out' or even also experiencing a taste hallucination (also usually obnoxious).

Interestingly, since many antiepileptic medications (AED's) are often used for psychiatric conditions that include psychosis (Bipolar, Schizophrenia), the patient may be having simple partial seizures but it's symptoms are misinterpreted as being part of the psychiatric disorder, and the symptoms may only pop up if medication is being changed or lowered. Medications would include Lamictal, Topomax, Keppra, Depakote, Trileptal. With most other causes, like tumors or schizophrenia (sorry, I can't do 'sz' because that's the abreveation we use for 'seizure'!), anyway, with most of these other causes, the hallucination lasts longer than it does for a seizure. Seizure-caused hallucinations are typically very brief, although they can certainly happen repeatedly throughout the day or night.

People often think of epilepsy seizures as being something that involves convulsions and loss of consciousness. That's not true. Temporal lobe epilepsies are *the* most common type of epilepsy, and the ones categorized as 'simple partial' specifically do NOT involve loss of consciousness, and certainly don't involve convulsions.

And to clarify, sometimes a simple partial seizure that has sensory symptoms (like hallucinations) can evolve into more traditional generalized seizures that involve convulsions, or even what's called "complex partial" which usually result in brief loss of awareness, but the symptoms are lip smacking, finger movements like picking at clothes, eye blinking, or even something like bicycling movements of the legs. The patient might 'look' like they are awake and aware, but they will not respond during the seizure if you try to engage. Brief simple partial sensory seizures preceding more involved seizures (with loss of consciousness) are called auras. Sensory aura's before a migraine are also very common.

Determining the cause of sensory hallucinations can be difficult. An electroencephalogram (EEG) is often one of the first tests, but temporal lobe seizures, and sensory-symptom seizures are often too deep in the brain to be picked up by scalp electrodes. MRI's and CT scans can help with looking for space occupying lesions and/or blood flow problems or injury to the transmission of impulses in the brain. If nothing is found, and the symptoms are disruptive to life, AED's may be tried, and if they provide no relief, electrodes can be surgically inserted to evaluate deeper parts of the brain in order to evaluate the patient as a candidate for surgery to remove the usually very small tissue in the brain that is causing the seizures.

This may be a whole lot more than you ever wanted to know... but since you asked :-)

Your response was totally enlightening, so even though I'm not the OP or anything... Thank you! I want to go into some field of neuroscience eventually, so I get all nerd-happy when I read this kind of stuff!! Hehe

I've been curious, myself, about the possibility of having temporal lobe epilepsy... Especially since I'm more likely to get migraines before/after psychosis & I often also get balance/hyperactivity issues alongside. But since my episodes often last too long & occur too often, that ruled it out for me mostly. So I appreciate that elaboration.

Fascinating stuff, Crescent. I often wondered if Tsunami was having seizures, and his doctors must suspect it too, because they keep running tests for it.

*whew* I'm so glad to know I'm not the only one like that.. and I'm especially glad that I at least didn't bore you to tears!

and well, the only way to know for sure (and remember, other insults to the brain can cause these symptoms that last longer) is to see a neurologist. Even then, let me tell you, two incredibly competent epileptologists (a sub-specialty in neurology) can really duke it out over interpretation and diagnosis. Sometimes, it's really hard to know until you open that brain up. Your complaints about balance issues are concerning - balance & coordination is the job of the cerebellum, which is right above your neck. I'd suggest you go ahead and get worked up by a neurologist, because you have a wide variety of troublesome symptoms that deserve evaluation. And remember, symptoms lasting too long to qualify as simple partial seizures does not mean they aren't caused by something else that would likely result in symptoms that last longer, such as a lesion or other injury.

Well.. and like I said.. a lot of sensory symptoms are caused by deeper structures in the brain. Seizures that have symptoms of sudden and extreme changes in emotion (like fear, panic, rage, and elation) are seated in the amygdala.. very deep spot. In order to diagnose (which might definitely be worth it if you're thought to have schizophrenia, it doesn't respond to treatment, and they suspect seizures) they may have to take a section of the skull off and place grid electrodes - often even stimulating different parts of the brain in an attempt to provoke the symptoms in order to identify it (and yes, the patient is kind of awake). A little less invasive of a test would be an EEG recording done from electrode needles inserted in the temporal lobes in front of your ear).

Thank you Crescent Moon for all of this great info! I'm seeing my primary care dr soon and I will be bringing this up. The scent for me last days up to a week, so it isn't brief, not sure what that could mean. It also goes away for days or weeks at a time too.

Days or weeks at a time would probably rule out seizures, but there is something going on along your olfactory tract. You'll probably need a CT and MRI.

Best of luck in finding out what's going on!