Exorcists identify 3 categories of activity that open a person to demonic possession
Exorcists are in general agreement as to how a person becomes possessed by demons. As one exorcist says, “The darkness is there, waiting to receive an invitation.”
Exorcists identify three categories of activities and experiences that open a person to demonic possession. We can think of these categories as doors for demonic attacks: they invite demons in, but they do not always result in possession. In fact, as we shall see, full-fledged demonic possession may be extremely rare—depending upon whose opinion we accept.
The first category is referred to as patterns of sin. This does not mean simply being a sinner, since all of us are sinners. Rather, this refers to people who have a habit of serious sin that they like, are attached to, and have no desire or intention of stopping. There is a conscious decision to give one’s self over to the sin. Demons can see this as an invitation to their activity.
The second category of influences that invite demons into one’s life is the occult. Occult practices include Satanism, the use of tarot cards and the Ouija board, and consulting psychics and mediums. This also includes necromancy, the attempt to consult with spirits of the dead for the sake of learning hidden knowledge or future events.
Being a victim of trauma or abuse is a third category of experience that can open the door to demonic possession. The trauma may be witnessing a murder, suicide, or horrific accident; the abuse may be sexual, physical, or psychological. One exorcist explains that those who go through these experiences can end up living in the dark emotions of anger, rage, resentment, and revenge. He stressed the importance of such victims getting the psychological and spiritual help that they need, in order to have some degree of healing. If they do not, those emotions can weaken their relationship with God, and simultaneously be an opening to a relationship with evil spirits.
According to the Rite of Exorcism, the exorcist should command demons to reveal whether they are held or detained in the possessed individual by means of magicam, aut malefica signa, vel instrumenta. English versions of the rite usually translate this phrase as necromancy, or evil signs, or amulets, though the word magicam may also be translated as magic. In regard to the malefica insturmenta, an evil instrument or amulet, the exorcist should order the possessed individual to reveal any cursed objects he may have concealed on (or in, if swallowed) his person. An object that is cursed in some way is not inherently evil, but the devil might be more likely to use it for his evil purposes.