Insects in Psychiatry
Insects have profoundly influenced our culture through time, and it is therefore not surprising that they feature prominently in some psychiatric disorders. Historically, there has been considerable confusion and definitional overlap between insect phobias, delusions of parasitosis and illusions of parasitosis. Insect phobias involve an irrational fear of insects without the insect bites or infestation actually being experienced; whereas in delusions of parasitosis the patient believes that the bites or infestations actually occur. Illusions of parasitosis result from real environmental stimuli which are incorrectly perceived as being due to insects. Clinically, it is important to differentiate these conditions both from each other and from conditions with similar symptoms: the different psychologies involved should help direct appropriate treatment.
Insects are an integral and influential part of our culture as illustrated by their infiltration of our language, arts, history, philosophy, and religion. However, as human society has become progressively more urbanized, insects have become progressively more estranged. As significant but increasingly intangible elements of our culture, insects now feature prominently in certain psychiatric disorders, much as do religious and extraterrestrial elements. Our perception of insects can range from appropriate apprehension when faced with the possibility of a bee sting, through subclinical and clinical insect phobias, to full blown psychotic delusions of insect attacks and infestations. We are concerned in this paper only with the clinical syndromes involving insects, since it is in this area that most confusion has arisen historically. Up until some twenty years ago most authors dealing with insects in psychiatry discussed several different syndromes under the same name. Authors are now increasingly aware of the distinctions bet-ween delusions of parasitosis, insect phobias, and illusions, but some overlap and confusion never the less remains. No paper to date has discussed these syndromes specifically to differentiate between them.
[Insect phobia; includes acarophobia (mites: scabies)
and arachnophobia (spiders)].
Most people are at least wary, if not fearful, of certain insects (more correctly arthropods). This may be a reasonable fear based on knowledge or experience (bees, wasps, spiders, mosquitoes), an unreasonable but culturally understandable repulsion (cockroaches or flies), or a misplaced fearresulting from inadequate information (dragonflies, moths, crickets). A true insect phobia, on the other hand, is defined by the following criteria:
- A persistent irrational fear of and compelling desire to avoid insects, mites, spiders, or similar phobic objects.
- Significant distress from the disturbance despite recognition by the individual that the fear is excessive or unreasonable.
- Not due to another mental disorder such as schizophrenia or obsessive compulsive disorder (modified from DSM III).
The condition must be differentiated from delusions of parasitosis and illusions of parasitosis (following), and from obsessive compulsive disorder and schizophrenia. This can sometimes be difficult, even for an experienced psychiatrist. For example, the phobic object may be an insect infestation; that is, the possibility of becoming infested by ectoparasites is the feared notion, not the parasites themselves (as distinct from a delusion in which an imaginary infestation is actually experienced). A phobia of penetration/filth can also lead to cleaning and sterilizing rituals identical to those seen in obsessive compulsive disorder. As pointed out by Olkowski and Olkowski (1976), the syndromes satisfying these criteria represent only the tip on an iceberg, with much unnecessary avoidance behavior never reaching a level where treatment is sought or necessary.
Although phobias probably occurred before recorded history, insects are less likely to have been phobic objects in the past. In hygienically urbanized western societies, many people have little first hand experience of insects other than flies and mosquitoes. Such urban societies are not as mentally or physically prepared for arthropod encounters as are rural communities (Coulson and Witter 1984).
It is not unreasonable to assume that the danger and annoyance insects have caused to man over the millennia has resulted in an ingrained fear of insects in most societies. Bites and stings to humans and domestic animals act not only as stimulators of toxic and allergic reactions, but insects have been the vectors of potentially fatal diseases since prehistoric times. It is only very recently that such diseases as yellow fever and plague have come under control. Others, like malaria, remain a significant problem. An almost Jungian fear of insects can therefore be rationalized in all of us even if in the form of conditioned over-reactions. Fazio (1972) has suggested that the latter are largely a result of “vicarious learning family dependency” rather than of traumatic conditioning; most of his subjects lacked any real contact with the feared insects. Such explanations, however, are more likely to underlie the non-clinical end of the phobic spectrum than they are to underlie phobias satisfying the criteria set out above. In these clinical cases, as in other phobias, the more likely cause is a displacement of diffuse anxiety to an external focus which can be avoided. The choice of insects as the phobic object may be random, symbolic, or perfectly logical. When symbolic the insects often represent filth and soiling. They have also been interpreted as symbols of sexual penetration which cannot be eradicated (Schrut and Waldon 1963). The “logical” choice of insects as phobic objects is well described by Kolansky (1960). In a case of infantile neurosis and insect phobia involving a little girl, he describes how the symptoms resulted from her being told that her sister with pneumonia had died from a `bug.’ Finally it is worth mentioning the interpretation of Savory (1964). He suggests that the fear of insects is a result of their rapid movements leading to retinal image movements similar to those involved in falling. Adrenaline release and an increase in muscle tone follow, and these are the factors which lead the brain to interpret `fright’- much like Jane Lange’s theory of “feeling sorry because we cry.”
Treatment and Prognosis
The role of the entomologist is primarily to dispel any possible misconceptions which may be exacerbating the phobia. Education here is a crucial element (for example to clarify the harmlessness of dragonflies). To put insects in a more positive light, and to remove such fears as may be passed on from parents, zoos and museums can play an integral educational role. The live insect exhibit at the Los Angeles Natural History Museum is an example: volunteers take insects from their cages and hold them out for visitors to fondle – which most children do (Mofet 1979!)
Specialist treatment will be as for other phobias, and is largely determined by the therapist’s individual preferences. Methods reported in the literature include supportive psychotherapy, desensitization (Fazio and Erk 1973), insight psychotherapy, combination of therapies (possibly including group therapy), drug therapy (anxiolytics), modeling (Denney and Sullivan 1976), hypnotic regression and reframing (Domangue 1985), and implosive therapy (Fazio 1972).
For chronic phobias the prognosis is good if the underlying conflict can be dealt with. If the conflict is deep and exhibits symbolic elements, the prognosis is worse, and the presence of compulsive symptoms such as cleaning makes it worse still (c.f. delusions of parasitosis).
most medical graduates will have a basic knowledge of entomology, and will be able to reassure patients about the harmlessness of phobic objects such as dragonflies and moths. Reference to a basic entomology text, or a quick call to an entomologist, should be encouraged to help clarify any detailed misconception that may be contributing to the phobia. It is useful to remember that only blood feeders (mosquitoes, fleas, ticks, bedbugs) actively pursue humans. The more common phobic objects (spiders, bees) never bite or sting unless trapped or seriously threatened. Although the former category comprises insects which are associated with poverty or poor sanitation, insects in the latter category, which are beneficial to man, are feared the most (Olkowski and Olkowski 1976).
[Ekbom syndrome, monosymptomatic hypochondriasis, formication].
Although rarely mentioned in textbooks of psychiatry, and not classifiable in DSM III (Maier 1987), many European authors feel that `monosymptomatic hypochondriases’ deserve their own diagnostic label (Bishop 1980 and references therein). The syndromes include dysmorphophobia, olfactory reference syndrome, and, most prominently, delusions of parasitosis. Ekbom (1938) was the first to clearly differentiate the syndrome from entomophobia, and his name is often used eponymously therewith. He used the term Dermato-zoenwahn, which is still current in the German literature (Musalek et al 1988). For English speakers, the term delusions of parasitosis, first used by Wilson and Miller (1946) appears to be the most appropriate, unless one has a penchant for eponyms.
An unshakable false belief that live organisms are present in the skin (Obermeyer 1961). These organisms range from insects to worms and bacteria (Wilson and Miller 1946), the type often depending upon the parasitological knowledge of the patient. It is important to note that delusions of parasitosis may be a symptom complex rather than a disease entity, as it is found in a variety of physical and mental diseases; nevertheless, it is often the only recognizable abnormal element. Where the delusion of parasitosis is not the major symptom, as in Delirium Tremens, it may be better to use the term `formication.’ In this way, delusions of parasitosis should eventually become restricted to a single disease entity (or disappear from use) as our nosological knowledge increases. Maier (1987) suggests that the reines Dermatozoenwahns (true delusions of parasitosis) may be those not involving organically based diseases or schizophrenia. In his original description, Ekbom himself did not include delusions of parasitosis which were part of complex frame works, only those in which delusions of parasitosis were the sole psychiatric symptom (i.e. primary delusions).
The condition must be differentiated from entomophobia (above). Similar symptoms may occur in a number of other conditions which, as discussed, are perhaps best other
wise classified (drug induced organic brain syndrome (Bishop 1980, Bourgeois et al 1981, Todd 1968), schizophrenia, factitial dermatitis, manic depressive psychosis).
The most important diagnostic consideration is an awareness of the fact that patients with delusions of parasitosis experience the state of being infested. This is fundamentally different from having a fear of becoming infested, which falls into the category of entomophobia. This distinction has not been made clearly in the literature and is often a source of confusion between phobia and delusion( e.g. Galeota 1966). The phobia immediately entails a better prognosis, as reality testing remains unimpaired.
The earliest well documented case appears to be that described by Thibierge(1894), although he applied the term “Acarophobe.” The case is clearly one of delusions of parasitosis according to Ekbom’s later (1938) definition.
An obsessional, anankastic personality is a predisposing factor in most suffers (Bourgeois et al 1981), and female cases are most frequently reported (Berrios 1985, Wilson and Miller 1946).
The syndrome is often preceded by an original and very real arthropod infestation acting as a `trigger’ (Schrut and Waldron 1963). Senile pruritus or other tactile sensory disorders may also act as triggers, which become elaborated into a delusion and are later `fixed’ (Wilson and Miller 1946, Berrios 1985). Possible triggers therefore also include systemic disease (diabetes, TB, syphilis) and deficiency states such as pellagra. These disorders (as well as real infestations!) must obviously be identified in order for treatment to be appropriate.
Presenting complaints include itching, biting, stinging, burning and crawling sensations. Insects are often described as black or white, jumping, and sometimes emerging from cosmetics or toothpaste (Waldron 1962). The `matchbox’ sign, where the patient brings specimens at the first visit, is ominous. Microscopic examination of the contents usually reveals only lint, scabs, or other household dust. Such negative findings invariably lead to more intense collection and presentation of specimens (Schrutt and Waldron 1963). One can often elicit a list of attempted treatments including all imaginable varieties of detergents, balms and poisons. More rarely, the presenting complaint is one of auditory hallucination (Wilson and Miller 1946).
Patients most commonly present to dermatologists (if skin changes are present) or pest control officers (if they are not). In the former case excoriations are classically produced by the fingernails and there may also be signs of chemical burns as a result of attempts to kill the parasites. The patient is compelled to dig the parasites out, especially before going to bed, and often resorts to the use of a knife, tweezers or other sharp implement, leaving skin lesions consistent therewith. For those patients presenting to pest control officers, Gage (1957) and Galeota (1966) both warn of the risk of making treatment even harder by `fixing’ the delusion with reinforcing statements or insecticide applications.
The symptoms may be carried over, or passed on by suggestion, to other members of the family. Folie ? deux occurs with a surprisingly high frequency. If a disease entity delusions of parasitosis exists per se, it may well lie within this category as a primary delusion (Evans and Merskey 1972).
Treatment and Prognosis
Delusions of parasitosis are far more common than is indicated by the literature: almost every dermatologist knows of a couple of cases (Bourgeois et al 1981), as do most entomologists and pest control officers (Galeota 1966, Gage 1957, Weinstein pers obs.).
Despite such an apparent frequency of affliction, there is no generally accepted approach to treatment, with many therapists (perhaps reasonably) adopting the attitude that “some treatment, scientific or foolish, which the patient can be made to apply with confidence, will bring about some relief” (Smith 1934). Psychotherapy and psychoanalysis have been successful in treating delusions of parasitosis associated with repressed conflicts over sexuality and aggression (Torch and Bishop 1981) and drug treatment with pimozide can provide significant relief of both itch and delusions (Hamann and Avnstorp 1982). A number of other treatments, including ECT, are used less frequently or have fallen out of favor.
There is an ongoing debate as to whether dermatologists or psychiatrists should treat patients with delusions of parasitosis. Dermat-ologists often argue that although psychiatrists are better qualified to deal with the delusions, the nature of the patients is such that they are likely to be lost to treatment should a psychiatrist be mentioned. It is therefore better for the dermatologist to maintain treatment on pimozide for example, than it is for the patient not to be treated at all (Hahmann and Avnstorp 1982). A good dermatologist should ideally be able to present the “second opinion” sought from the psychiatrist in such a way as to not loose the patient to further treatment. Obermeyer (1961) suggests that the dermatologist screen and refer sufferers along the following lines:
Depression or psychosis present – immediate referral to a psychiatrist;
Patient recognizing emotional involvement – referral to psychotherapist;
Patient denying emotional involvement and hostile to psychiatric concepts – supportive or drug therapy administered by dermatologist.
The prognosis is very variable, and often dependent on those other diagnosed or undiagnosed disease complexes which contribute to the symptomatology. The formication of Delirium Tremens for example has an excellent prognosis, but it is worse in schizophrenia and affective disorders. The prognosis is very poor in paranoid conditions since these assessments are usually not suitable for psychotherapy/ analysis. Obermeyer (1961) describes paranoiacs who would dig into their skins “up to the time of involuntary parting, and who probably still dig, under somebody else’s auspices”!
Although most therapists will see patients who have already been screened for genuine infestations, anyone involved with the case has the responsibility to ensure that another dermatologist or parasitologist rechecks negative findings if any doubt whatsoever exists. Despite the presence of personality traits or psychiatric symptoms which corroborate a diagnosis of delusions of parasitosis, the patient is sometimes infested. The reader is referred to a paper by Traver (1951) where she describes her suffering through a seven year infestation by the mite Dermatophagoides schermetewskyi Bogdanow. Unlike Sarcoptes scabei which is easily located in epidermal burrows, this beastie inhabits the dermis, and could not be found. The response of the physicians she consulted was quite predictable when Traver presented with formication, classical self induced excoriation, a history of trying a long list of chemical remedies, and two adult female family members living with her with identical symptoms.
The details of natural history related by patients are often quite complex (Miller 1954), and depend upon the patients’ previous entomological knowledge. Imagined animals range from fleas, lice and scabies through itch-mites, bedbugs and worms, to nondescript “black things” and insects new to science (Wilson and Miller 1946). In assessing the feasibility of the details related by the patient, it is important to compare these with existing knowledge.
A rudimentary understanding of arachnid life cycles, biology and behavior, if not already known, is easily obtained by any therapist by consulting medical entomology texts or local entomologists. Remember that psychiatric patients can be the unwilling hosts of lice, mites, and bedbugs as easily as can anyone else.
Unlike delusions of parasitosis, illusions of parasitosis result from actual environmental stimuli (Heidbreder and Waldron 1971). The stimuli are incorrectly interpreted and are attributed to insects or other small organisms which are then thought to be biting or infesting the person, their home, and/or their working environment.
Illusions of parasitosis are particularly common in groups. Their “contagious” nature parallels the high incidence of folie ? deux in delusions of parasitosis, and although not a psychiatric disorder per se, an awareness of such illusions may help to explain `triggering,’ suggestive cross infection, and psychological enhancement of both insect phobias and delusions of parasitosis.
Illusions of parasitosis can be readily differentiated from both entomophobia and delusion of parasitosis by considering a few simple questions as outlined in the following table (adapted from Waldron 1972).
The phenomenon was first studied seriously in the context of “mass entomophobia” due to “cable mites” and “paper lice” in offices and laboratory environments in the 1960’s. The subject borders on forensic entomology: see for example the classic account of how dermatitis caused by a persistent laboratory infestation of “cable mites” was eventually eliminated when rockwool aerosol was recognized as issuing from the laboratory air-vents (Scott and Clinton 1967). Today, such a case would undoubtedly have resulted in several law suits.
Possibly the most notable aspect of illusions is the ease with which symptoms are transmitted. Dermatitis, itching, formication and bites (in this case obviously proportional to the causative stimulus) are the most common symptoms, and, in co-workers, a phobia of being affected. Over one hundred and fifty people may be affected simultaneously, the symptoms also being transmissible to unaffected individuals by suggestion. Females are most commonly affected, and associations are often made between the symptoms and personal office problems, leading to an overall loss of morale and efficiency. Environmental factors may be predisposing, such as a poor working environment, dull routine work, or too much pressure. Apart from obviously physical agents such as the rockwool mentioned above, the genesis of an outbreak has been broadly attributed to both transposition of symptoms and transmission by suggestion.
Transposition of symptoms may follow a true or triggering infestation, such as fleas at home. Resulting bites may be associated with a situation at the office, and the problem is thus transposed from one environment to another (Waldron 1972). Transmission of symptoms (e.g. itching) from one person to another may take place if the symptoms are in turn associated with the second person’s own personal office problems (ibid). The symptoms are often further exaggerated for secondary gain.
Treatment and prognosis
As with delusions of parasitosis, the importance of excluding a true entomological cause cannot be over-emphasized. An experienced pest-control officer or competent industrial epidemiologist should be consulted. In my own former laboratory, several people including myself were repeatedly and frustratingly bitten by something we could not locate for many days. “Starling lice” (Ornithonyssus sp. – a mite) were the cause, and pigeon and starling nests were subsequently removed from the eaves of the building. Non-entomological causes may be identified with the help of some detailed detective work, as in the case of Scott and Clinton’s “cable mites” (1967). The therapist’s role is to be aware of the possibility of such illusions in the context of their interactions with the disorders discussed previously.
In the absence of complicating factors, the illusions obviously resolve once the physical stimulus is identified and eliminated. Symptoms are also substantially alleviated by action taken in deference to the psychological state of the workers, such as their working environment, chores and work pressure (Scott and Clinton 1967).
“Cable mites” and “paper lice” are non-existent entities. Those arthropods which are potential pests to man have well defined behavior and habitat requirements, all of which can be discovered in medical entomology texts or in consultation with local entomologists. A comparison of known facts to reported complaints will, as in the delusions of parasitosis, tend to support or reject the involvement of insects or other arthropods.
Entomological effects of psychiatric conditions
Although entomological effects of psychiatric conditions cannot be considered significant in the current context, they are mentioned here for completeness and for interest.
Coulson and Witter (1984) classify human responses to arthropods in 5 categories. When confronted with insects or damage they have caused people either:
- Go hysterical – i.e. exhibit entomophobia
- Go on a killing spree (“the only good insect is a dead insect”)
- Tolerate the insects and plant damage once they understand that no serious or permanent harm can be done
- Are indifferent or do not respond
- Go ‘environmental’, protect living things, and denounce all insecticides and repellents.
Which response is likely depends upon the person’s knowledge and experience as well as the type and number of insects. At a community level, the uninformed extrapolations made from germ theory have resulted in excessive `cleanliness,’ with overuse of insecticides, elimination of natural predators, and development of insecticide resistance (Olkowski and Olkowski 1976). At an individual level, the more interesting cases arise, such as the traditional example of the arachnophobic man who obsessively killed every spider in his house and garden. Having removed all predators, the pest resurgence in his vegetable patch was phenomenal! My favorite case report is that of an Irish woman who passed thousands of coprophagous beetles of the genus Blaps in her stools. She presumably ingested eggs or larvae inadvertently when she ate clay and chalk taken from the graves of priests (Westwood 1839, cited in Matthews 1975)!
Fortunately, people with entomologically oriented psychiatric disorders are (arguably) not frequently in positions of political or economic power, and such people do not therefore affect insects in the ecological sense.return
I wish to thank the late Charles Hogue for his early encouragement in pursuing this topic, and Dexter Sear for subsequently facilitating the project. Jack White helped with references and Agnes Feld typed the manuscript.