Perception › Hallucination › Auditory Hallucination

Thought Echo

Thought echo is a specific, named variant of auditory hallucination in which a person hears their own thoughts spoken aloud, as if by an external voice, either at the same moment the thought occurs or immediately after it. It is usually classed as one of the first-rank features clinicians are taught to screen for in psychotic illness, though on its own it does not confirm any particular diagnosis.

Historically this was described as sitting at the boundary between an inner thought and an outer perception: the content is entirely the person's own, but the experience has the perceptual quality of hearing it from outside.

Also known as

Gedankenlautwerden

The German term for the variant where thoughts are heard out loud as they occur to the person, rather than being repeated afterward.

Écho de la pensée

The French term traditionally used for the variant where the thought is heard echoed back a moment after it occurs.

Recognition features

• The voice repeats or speaks the patient's own thoughts, word for word, rather than commenting on the patient's actions or holding an independent conversation
• Timing is the key distinguishing detail: either simultaneous with the thought, or following it by a short, consistent delay
• The patient usually recognises the content as their own thought, even though the experience feels like hearing an external voice

Eliciting it at interview

• Ask specifically: "When you have a thought, do you ever hear it spoken out loud, as if someone were saying it?"
• Clarify timing directly, since this is what separates thought echo from a voice that comments on or discusses the patient more generally: "Does the voice say it at the same time you're thinking it, or a moment afterwards?"
• Avoid leading the patient toward a first-rank-symptom checklist answer; let them describe the experience in their own words before naming it

Distinguishing features

• Differs from a running-commentary voice, which narrates the patient's actions rather than repeating their thoughts
• Differs from thought broadcasting, which is a belief that thoughts are known to others, not an auditory experience of hearing them
• Differs from ordinary inner speech (the everyday experience of 'hearing' one's own thoughts silently), because it carries the perceptual force of an external voice

Common misconceptions

• That thought echo is the same thing as thought insertion; thought echo is a perceptual phenomenon (a hallucination), whereas thought insertion is a delusional belief about the origin of a thought
• That describing this symptom automatically means a diagnosis of schizophrenia; first-rank features raise the likelihood of a psychotic illness but are not diagnostic in isolation

Related phenomena

Auditory Hallucination · Running Commentary Voices · Thought Broadcasting

Diagnostically relevant to

Schizophrenia (links open the DSM-5 Learning Lab)

Practice this

A patient reports that, as soon as she thinks something, she hears her own thought spoken aloud by a voice, word for word, a moment later — she recognises the words as her own thought, but experiences the voice as external and real, not as her own inner speech. What is this? · A patient reports hearing a voice that narrates what he is doing throughout the day — "he is getting up, he is walking to the kitchen" — but the voice never repeats anything he has actually thought. Before revealing the answer: is this thought echo? · A patient describes hearing a voice that seems tightly linked to what they are doing or thinking. Before revealing the answer, decide what single question distinguishes running commentary voices from thought echo. · A patient reports a disturbance in which her private thoughts are somehow no longer entirely her own affair. Before revealing the answer, decide what distinguishes thought echo from thought broadcasting. · A patient has mentioned hearing a voice that seems connected to her own thinking. Before revealing the answer, decide how you would explore whether this is thought echo. · Explain why the timing of the voice relative to the patient's thought is considered the single most useful detail to establish when assessing possible thought echo.

Illustration

A 31-year-old man describes it this way: "When I think about making tea, I hear it repeated back half a second later, like someone else in the room saying 'he's going to make tea' right after I've thought it. It's not my voice, and it's not comforting." He finds it distracting more than frightening and has told no one about it before this interview.

References

• Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 3, 'Disorders of Perception'.