What is the difference between demonic possession and obsession?

The difference lies in degree and in the place of the action: in possession, the demon takes hold of the body and blocks, during the crisis, the higher faculties of the soul; in obsession, the siege remains external – thoughts, images, persistent disturbances – and the person’s freedom remains intact, with full moral responsibility for their acts. One is dominion, the other is siege.

The distinction is no curiosity: pastoral discernment and the decision whether to resort to the major exorcism depend on it. It deserves to be set out with the sources in hand, avoiding the two precipices contemporary practical demonology identifies: the rationalist denial that dissolves the demon into a symbol and the superstitious fascination that turns him into a spectacle [PAD-26, Demonologia Prática Contemporânea, Part I, p. 11].

What is diabolical possession?

Possession designates the gravest form of extraordinary diabolical influence. «It consists in a true taking of possession, a dominion that Satan exercises directly over the body and indirectly over the soul, in such a way that the higher powers of the soul and even consciousness are excluded» [PAD-26, op. cit., p. 5, literal translation]. During the crisis the intellectual and volitional faculty is blocked, and the person becomes an instrument of the spirit, forced to speak and to move, without moral responsibility for the acts committed. Since the dominion is discontinuous, episodes of crisis alternate with moments of calm.

What is diabolical obsession?

In obsession the demon acts from outside: a siege of thoughts, obsessive images, physical or environmental disturbances, without taking hold of the body or annulling the will. The difference rests on a Thomistic principle that governs the whole morality of temptation: «The demon suggests, he does not constrain» [PAD-26, op. cit., p. 4, literal translation]. Thomas Aquinas distinguishes precisely what the demon can and cannot do: he can act on the imagination and the senses, suggest, move bodies locally, produce sensible effects within the limits of created nature; he cannot change the human will in a necessitating way, nor know futures that depend on free will, nor the secrets of the heart, reserved to God [PAD-26, op. cit., p. 4].

The signs of the Roman Ritual

The Roman Ritual sets out the indications pointing to possession: speaking or understanding a language unknown to the subject, knowing distant and hidden things, manifesting strength far beyond the person’s age and condition [PAD-26, op. cit., p. 5]. Note the terminology: the Latin tradition of the De exorcizandis obsessis (1614) called obsessi those we would today call possessed – hence some authors translate «diabolical obsession» where current English says possession [cf. H. Moll, The signs laid down in the Roman Ritual for recognising diabolical obsession].

The underlying criterion is natural impossibility: when effects appear that absolutely exceed the capacity of nature, joined to aversion for the sacred, reason concludes that a preternatural cause has intervened – not the divine supernatural, but the action of a spiritual creature superior to the sensible order and inferior to God [PAD-26, op. cit., p. 4].

Before speaking of a demon: rule out the natural cause

The Church’s prudence comes before any rite. «Behind every epileptic no demon is hiding», and the split personality studied by psychiatry may even manifest hatred of the sacred, but it does not produce languages never learned, knowledge of unknown facts, or effects exceeding human possibility [PAD-26, op. cit., p. 6, literal translation]. The same text adds the sober note many forget: «Possession is today, in the light of present knowledge, a rather rare phenomenon».

Discernment is organised in three stages before any major exorcism – listening, confrontation and prayer – grounded in the very conduct of Christ in Mk 9:17-29, who investigates, asks how long the affliction has lasted, and only then commands [PAD-26, op. cit., p. 6].

The exorcism: what it is and who performs it

The Catechism defines it precisely: «Cum Ecclesia publice et auctoritative nomine Iesu Christi petit ut persona vel obiectum protegatur contra Maligni potestatem et a eius dominatione subtrahatur, exorcismus habetur.» – in literal translation, «when the Church asks publicly and authoritatively, in the name of Jesus Christ, that a person or object be protected against the power of the Evil One and withdrawn from his dominion, there is exorcism» [Catechism of the Catholic Church, n. 1673, cited in PAD-26, p. 7].

The major exorcism is a public sacramental reserved to the priest mandated by the bishop (can. 1172 of the 1983 Code, Ritual De exorcismis of 1999), and the canon requires four qualities in this order: piety, knowledge, prudence and integrity of life [PAD-26, op. cit., pp. 11-12]. The order is not accidental – piety precedes knowledge.

The gospel sets the model in the healing of the boy with a mute spirit: «Ego tibi praecipio: exi ab eo, et amplius ne introeas in eum. […] Hoc genus in nullo potest exire nisi in oratione et ieiunio.» – «I command you: come out of him and enter him no more. […] This kind can come out by nothing but prayer and fasting» (Mk 9:25.29, Vulgate, literal translation). When the demon does not obey, something failed in the minister, never in Christ [PAD-26, op. cit., p. 7]. These spirits are fallen angels, real and personal but limited creatures, already conquered by Christ on the Cross – and tradition entrusts the defence of the faithful to the archangel Michael.

Frequently asked questions

Is a possessed person responsible for what they do?

During the crisis of possession, no: the higher powers of the soul are blocked and the person acts as an instrument, without moral responsibility. Outside the crisis, and in every case of obsession, responsibility remains whole.

What are the signs of possession according to the Roman Ritual?

Speaking or understanding a language unknown to the subject, knowing distant and hidden things, and manifesting strength far above the person’s age and condition – always after natural causes have been ruled out.

Is possession frequent?

No. In the light of present knowledge it is a rather rare phenomenon, and its study demands interdisciplinary collaboration among theologians, physicians and psychiatrists.

Can any priest perform an exorcism?

No. The major exorcism is a public sacramental reserved to the priest who has received a mandate from the bishop, according to canon 1172.