Ablutophobia A fear of washing - or ablutophobia, from the Latin abluere, to wash, and the Greek phobia, or fear - especially affects children. It is often a temporary terror, experienced in infancy, though in some cases it can last for years. A seventeen-year-old girl once told the American psychologist Granville Stanley Hall that until the age of eleven she used to scream in horror if bathed. Another teenager informed him: ''To be washed always made me stiffen out, my eyes bulge, and I was almost convulsed with fear.'' The fear of washing was common in France in the early nineteenth century, when many believed that dirt was a shield against disease and the stink of sweat was proof of health and sexual vigour. As the historian Steven Zdatny explains, thorough washing was in any case difficult in a society that considered nudity shameful. A woman in a rural French hospital was outraged by the suggestion that she take a bath. ''I am sixty-eight,'' she said indignantly, ''and never have I washed there!'' The upper classes were similarly fastidious.

''No one in my family ever took a bath!'' recalled the comtesse de Pange. ''The idea of plunging into water up to our necks seemed pagan.'' In the second half of the century, as scientists established a link between dirt and the spread of disease, teachers tried to teach modern hygiene practices to children who had never used a sponge or immersed themselves in water. The French army, too, tried to instil cleaner habits in its recruits, and in 1902 published a Manuel d''hygine that instructed soldiers to brush their teeth, scrub their bodies and wear underclothes. In Douai, northern France, a military commander ordered his men to forcibly clean a young artilleryman who claimed to be afraid of bathing. The soldiers dragged their dirty comrade into the bathhouse and held him under a shower. According to Zdatny, the artilleryman''s death eight days later was attributed to his shock and horror at the sensation of water on his skin. His fear, it seemed, had killed him.

i See also: aquaphobia, hydrophobia, mysophobia, thalassophobia Aboulomania In 1916 the American psychoanalyst Ralph W. Reed treated a pathologically indecisive bank clerk of twenty-two who was ''continually doubting the validity or correctness of anything he has done in the course of his daily duties''. Each time he added up a column of figures, the clerk felt compelled to check it, and then check it again. He made the same agonised return to every calculation, however trivial. Reed noted that this kind of mental paralysis often coincided with paranoid delusions: both were disabling doubts about what had happened or what might take place. He diagnosed the clerk with aboulomania. The term aboulomania - from the Greek a (without), boul (will) and mania (madness) - was coined by the neurologist William Alexander Hammond in 1883. Aboulomania, explained Hammond, was ''a form of insanity characterised by an inertness, torpor, or paralysis of the will''.

He described one patient, a Massachusetts man, who was seized by indecision when dressing or undressing himself. As soon as he started to take off one shoe, he would wonder whether he should take the other off first. He would switch helplessly between the shoes for several minutes, before deciding to walk around the room to deliberate on the matter. Then he might catch sight of himself in the mirror, and, noticing his necktie, think, ''Ah, of course that is the thing to take off first.'' But when he tried to remove the tie, he would again hesitate and become powerless. ''And so it went on, if he was left to himself,'' wrote Hammond, ''till it has frequently happened that daylight would find him still with every stitch of clothing on his body.'' In 1921 the French psychiatrist Pierre Janet described the feeling of ''incompleteness'' that affected such individuals, rendering them continually unsatisfied, as if something was missing. They ''watch themselves'', he wrote, ''and by dint of observations, through anxiety about themselves, they fall into a sort of perpetual auto-analysis.

They become psychologists; which is in its way a disease of the mind.'' Aboulomania is an obsession that springs from self-consciousness, Janet suggested, a disorder made possible by our tendency to reflect on our own thoughts. It seems odd to categorise a state of chronic uncertainty as a compulsion: an inability to make choices looks more like a fear of error than a passion for indecision. But by identifying pathological doubt as a mania, Hammond reminded us that it is not just an absence of conviction. Rather, it is a powerful emotional state, a turbulent and painful condition in which all possibilities are still available; several futures are jostling and nothing has been closed off. i See also: arithmomania, mysophobia, syllogomania Acarophobia Acarophobia (from the Greek akari, or mite) is an extreme fear of tiny insects, first identified by the French dermatologist Georges Thibierge in 1894, which can develop into a belief that minuscule creatures have invaded the body. The itchy feeling of ''formication'' may be caused by the imagination alone, or by a physical condition such as shingles, tuberculosis, syphilis, skin cancer, the menopause or malnutrition. It can also be provoked by substances such as pesticides, methamphetamine and cocaine.

Since itchiness is very suggestible, acarophobic delusions are sometimes transmitted from person to person. The public health officer William G. Waldron investigated several reports of biting insects in Los Angeles workplaces in the 1960s. At a flight-booking centre that he visited, all the female employees were experiencing a tingling sensation and a slight ''pulling'' on their nylon stockings, just above the ankle. Waldron could find no insects on the premises, but he speculated that the women might be picking up a static electric charge from an uncovered telephone cable beneath their desks. He noticed that morale among the 150 employees was low. Perhaps, he thought, the oppressive working conditions were contributing to their prickly unease - the workers sat at their desks for hours on end, making complex telephone bookings, while three bosses watched them constantly from a darkened booth at one end of the room. Waldron recommended that the airline company cover the phone cable and turn on the light in the supervision booth.

After this, the women told him, the itching stopped. In attempts to dislodge insects, some acarophobes gouge out the flesh of their faces, necks or arms, scalps, chests, armpits or groins. ''I found him stripped to the waist,'' wrote Luis Bu-uel after visiting the artist Salvador Dal'' in a Parisian hotel in the 1920s, ''an enormous bandage on his back. Apparently he thought he''d felt a "flea" or some other strange beast and had attacked his back with a razor blade. Bleeding profusely, he got the hotel manager to call a doctor, only to discover that the "flea" was in reality a pimple.'' Bu-uel''s film Un Chien Andalou, on which Dal'' collaborated in 1928, opens with a razor blade slicing into an eyeball, releasing a swell of jelly, and goes on to show a swarm of ants teeming from a man''s palm, the flesh erupting with alien life. i See also: arachnophobia, dermatillomania, entomophobia, zoophobia Acrophobia Andrea Verga, the Italian physician who invented the term acrophobia in 1887, himself suffered from a morbid fear of heights. An acrophobe, he explained, ''has palpitations on mounting a step-ladder, finds it unpleasant to ride on the top of a coach or to look out of even a first-storey window''.

Verga derived his term from the Greek acron, meaning peak, and described its chief symptom as the dizzy, spinning sensation known as vertigo. Almost 20 per cent of us have a fear of heights, and for about 5 per cent of us it is a terror. The condition is sometimes attributed to traumatic experience - the detective in Alfred Hitchcock''s Vertigo (1958) develops a horror of heights after seeing a fellow policeman fall to his death - but only about one in seven acrophobes can recall an incident of this kind. In fact, in 2002 a study of eleven- and eighteen-year-olds with acrophobia found that both groups had unusually little experience of heights. If anything, it seemed that their phobia had been caused or exacerbated by a lack of familiarity with high places. In 1897, Granville Stanley Hall analysed eighty-three accounts of acrophobia and other ''gravity-related'' fears, from which he deduced that the phobia was rooted in a primordial anxiety, an ''instinct-feeling'' that was ''incalculably more ancient than the intellect''. Many of Hall''s subjects said that when they found themselves in high places they experienced a ''sudden giddiness, nausea, tremor, gasping, or sense of smothering''. In response, they ''grew rigid, livid, clenched their hands and teeth''.

But, oddly, he noticed that many acrophobes seemed to fear not an accidental fall but their own ''jumping-off instinct''. ''Very common is the impulse,'' he wrote, ''usually very sudden, to hurl oneself down from towers, windows, roofs, bridges, high galleries in church or theatre, precipices, etc.'' Some acrophobes clung to railings or bystanders in order to stop themselves from plunging over a precipice and ''ending it all''. One man admitted that he was tempted by ''the exquisite pleasure of dropping''. Others were drawn to the ''beautiful sensation'' of leaping into the air, wrote Hall, imagining that they might be ''upborne by their clothes, a parasol, flapping hands or arms like wings''. Hall suggested that to be afraid of heights was to be afraid not only of a deathly plunge but also of o.