Specific phobias are very common in the general population. Once called "simple phobias", they correspond to intense, excessive and lasting fears of well-defined situations or objects, and do not correspond to agoraphobia or social phobia. The fear felt by the subject is therefore not related to the presence of another person, nor to the anticipation of unease or an incident that may occur in the feared situation. It is a "raw" fear, without any particular mental elaboration. The contact or even the sight of the feared object, a photo of a spider for example, can be enough to provoke an intense anxious reaction, even an escape response. The most frequent specific phobias concern animals (mice, snakes, insects, birds, dogs, etc.), blood and injuries or medical procedures such as injections, height or emptiness, storms or darkness. Most of these situations are reminiscent, directly or indirectly, of real dangers, and it is likely that these phobias derive from ancestral fears that were useful to the survival of the species. In some cases, however, there is also a history of personal "trauma" that may explain the onset of phobia in a particular person (the memory of being bitten by a dog, or almost falling off a roof or bridge, etc.). To the extent that these fears are limited to well-defined objects, their impact on daily life is generally quite low, either because the objects in question are not often encountered (snakes, storms), or because the person can easily avoid them (birds, height, etc.). However, some phobias can cause real disabilities, with significant consequences for health or social adaptation: inability to accept a blood sample or an MRI examination (see claustrophobia), inability to work at heights, fear of certain domestic animals, etc. Claustrophobia is an anxiety disorder that manifests itself as a fear of confined spaces. People with claustrophobia often fear the occurrence of a threatening event from which they cannot escape because they feel "stuck". They then fear they lack air and will suffocate, they can present certain signs like tremors and sweating. Anxiety may increase, possibly leading to panic attacks. Most of the time, the person with claustrophobia will be able to avoid the feared situation (such as lifts, tunnels, underground trains, cellars, etc.) by implementing avoidance strategies.