Not all hallucinations are disturbing, but most probably are. They can be categorized by which sense is involved or by cause. Schizophrenics often experience auditory hallucinations, hearing voices that are not actually present. Many people can experience olfactory hallucinations, usually smelling foul odors that no one else can detect. These are often caused by specific problems in the brain or nose. A classic cause is seizure in the temporal lobe of the brain.
Visual hallucinations aren’t that common and usually aren’t associated directly with mental illness as auditory ones are. Most of the time, visual hallucinations are caused by chemicals such as drugs, or by withdrawal from drugs. Sometimes they are caused by specific brain disorders. A classic cause of visual hallucination is delirium tremens, or acute alcohol withdrawal. Victims often have disturbing visual hallucinations (one of my favorites being skeletons fighting with swords on the IV pole, although in that case, the patient wasn’t all that disturbed by it).
As if that weren’t enough, alcohol withdrawal is often accompanied by an additional type of hallucination called formication (from Latin formica ant). This is a tactile hallucination usually described as a feeling of bugs crawling on the skin. It’s rarely pleasant.
Delusions differ from hallucinations. Rather than being a sensory problem, they are a thought problem. People with delusions believe something that is demonstrably false and cannot be convinced otherwise.
Which brings us to what is surely not the end of the story of “morgellons syndrome”. Over the last few years, patient advocacy groups have militated for further investigation of this putative skin disease. The disease is characterized by a variety of symptoms, most of which are cutaneous and include itching, sores, and foreign substances arising out of wounds. Most physicians view this as a variant of delusional parasitosis, an illness where people believe they are infested but no proof of infestation can be found.
Patients typically have a pattern of skin lesions indistinguishable from damage done by scratching, and the fibers and other substances, when analyzed, have been found to be common substances such as clothing fibers. Even a brief perusal of morgellons advocacy websites will demonstrate the hostility with which this analysis is viewed. Sufferers believe they are truly stricken—and they are. But the enemy is within rather than without. Their brains have convinced them that their skin is crawling with various sorts of things and they cannot be convinced otherwise.
A few years ago, the CDC decided to investigate what they have labelled “unexplained dermatopathy”. This week, the results of their study were published in PLoS ONE.
The investigators focused on Northern California, where there seemed to be many case reports. They sifted through charts and invited those who described the syndrome to join the study. What they found was that cases were rare, but were associated with significant disruption in quality of life. They also found a significant incidence of neuropsychiatric disorders. A remarkably large percentage of patients had hair samples testing positive for drug use, but the specific drugs are not reported, nor is the validity of the hair sampling technique.
In sum, there was a set of patients who reported disturbing skin sensations and wounds, who were disproportionately unhappy and may have been using drugs. But which way does the arrow of causation go? Does a mystery disease cause people to become depressed and use drugs, or does psychiatric disease and/or drug use cause a delusional syndrome? Delusions and hallucinations caused by psychiatric disease and substance use are well-documented. The other way ’round is a bit murkier.
Some clues are found in the study. Many cases began around the same time the internet picked up on morgellons suggesting a folie a deux/plusiers —a shared delusion (this also suffers from a correlation vs. causation problem). Also, the skin changes among patients were diverse, too diverse to be easily explained by a single non-psychiatric cause. Pathology findings most commonly showed skin changes due to sun exposure and trauma such as scratching. Finally, the “fibers” and other objects emerging from the skin were found to be common substances like threads from clothing and were not emerging from the skin but rather were enmeshed with skin debris.
This will not be the last word on this particular variant of delusional parasitosis. The definition of a delusion is a fixed, false belief, one that is not dislodged by data or knowledge. The inability to accept the diagnosis is part of the illness itself. The challenge to clinicians will be to treat these patients delicately, with respect, acknowledging their real distress and attempting to guide them toward proper treatment.
Pearson, M., Selby, J., Katz, K., Cantrell, V., Braden, C., Parise, M., Paddock, C., Lewin-Smith, M., Kalasinsky, V., Goldstein, F., Hightower, A., Papier, A., Lewis, B., Motipara, S., Eberhard, M., & , . (2012). Clinical, Epidemiologic, Histopathologic and Molecular Features of an Unexplained Dermopathy PLoS ONE, 7 (1) DOI: 10.1371/journal.pone.0029908