Thought & Speech

Obsession

An obsession is a thought, image, or urge that persists and dominates a person's mind against their will, despite their own awareness that it is pointless or has gone on far beyond any usefulness. The content is often deeply unwelcome to the person holding it — a devout person tormented by blasphemous thoughts, or a new parent by intrusive thoughts of harming their baby — which is part of what makes obsessions so distressing.

The essential feature, classically, is that the thought is recognised by the person as their own but appears against their will; this is what allows a mental event to be classed as an obsession at all, since only something that is normally under a person's control and could, in principle, be resisted can properly be called obsessional.

Also known as

Obsessional image

A vivid, intrusive mental picture that occupies the mind; can occasionally be so vivid that it is mistaken for a pseudohallucination.

Obsessional idea (rumination)

A persistent, dominating train of thought on a particular topic, which the person cannot help returning to.

Obsessional impulse

An urge to carry out an action, such as touching, counting, arranging objects, or something antisocial, which the person resists acting on in almost all cases.

Obsessional fear (obsessional phobia)

A groundless fear that the person recognises as excessive and without cause, distinguished from an ordinary or learned phobia by this quality of senselessness.

Recognition features

• The thought, image, or urge is recognised by the person as their own, not as coming from outside them
• It intrudes against the person's will and cannot easily be dismissed or ignored
• The person is aware that the thought is excessive, unreasonable, or purposeless, and this awareness itself often causes significant distress or guilt
• Content is frequently the opposite of what the person values or would wish to think, contributing to the distress

Eliciting it at interview

• Ask sensitively and directly, since obsessional content is often experienced as shameful: "Do you ever get thoughts, pictures, or urges that keep coming back into your mind, that you don't want and try to push away?"
• Clarify ownership explicitly by asking whether the thought feels like it is truly their own, just an unwanted one, rather than feeling as though it has been placed there from outside — this distinguishes an obsession from thought insertion
• Ask specifically about content the person may be reluctant to volunteer, such as thoughts of harming a child, since these are common but rarely raised spontaneously

Distinguishing features

• Differs fundamentally from thought insertion in that the obsessional thought is recognised as the person's own, however unwelcome, whereas an inserted thought is experienced as coming from an outside agency
• Differs from a delusion in that the person retains insight that the thought is excessive or irrational, rather than holding it as a fixed, unshakeable belief
• By definition, an obsession can only apply to thoughts, images, fears, and impulses — not to hallucinations or moods, since only something within a person's usual control can be called obsessional

Common misconceptions

• That obsessions always involve visible compulsive rituals; obsessional thoughts, images, and fears can occur, and cause significant distress, without any accompanying compulsive behaviour
• That having a disturbing intrusive thought means the person wants to act on it or is at risk of doing so; it is very unusual for an obsessed person to actually carry out an obsessional impulse, and the distress itself reflects how unwanted the thought is

Related phenomena

Compulsion · Thought Alienation

Diagnostically relevant to

Obsessive-Compulsive Disorder (links open the DSM-5 Learning Lab)

Practice this

A man is troubled by repeated, unwanted images of harming his own child, which he finds horrifying and completely contrary to how he actually feels. He recognises the thoughts as arising from his own mind, tries hard to resist them, and is acutely aware that they are excessive and irrational, which itself causes him great distress and guilt. What is this? · A woman describes recurrent thoughts of contamination that she finds distressing, but on further questioning she says she is not actually sure the thoughts are irrational — she feels genuinely convinced her hands are contaminated no matter how much she washes them, and this conviction does not waver even when shown clear evidence otherwise. Before revealing the answer: is this a straightforward obsession? · A man spends over an hour each morning checking that his front door is locked exactly seven times, finds the checking exhausting and pointless, and wishes he could simply stop, but feels compelled to continue regardless. Is this best understood as anankastic personality disorder? · A patient describes a repetitive urge and an accompanying repetitive action. Before revealing the answer, decide what distinguishes a compulsion from an obsession. · A patient describes an unwanted thought that keeps intruding into their mind. Before revealing the answer, decide what single question distinguishes an obsession from thought insertion. · A patient describes an unwanted thought. Before revealing the answer, decide what distinguishes thought alienation from an obsession. · You suspect a patient may be experiencing obsessions but they are reluctant to describe the content in detail. Before revealing the answer, decide how you would approach eliciting this. · Explain why the retained insight in an obsession — the person's own awareness that the thought is excessive or irrational — is itself a source of distress, rather than a reassuring feature.

Illustration

A new mother describes being seized, several times a day, by a vivid and horrifying mental image of dropping her infant down the stairs. She is deeply distressed by the image, recognises it as nonsensical and completely contrary to how she feels about her child, and has never come close to acting on it, but has started avoiding carrying the baby near the staircase altogether out of fear of the thought itself.

References

• Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 4, 'Disorders of Thought and Speech'.