Thought Blocking
Thought blocking is a sudden, involuntary halt in the flow of thinking or speech, experienced as though the mind has simply gone empty. The person is mid-thought or mid-sentence one moment and unable to continue the next, and afterwards they usually cannot say what they had been about to say.
It has traditionally been classed as a disorder of the continuity of thought, distinct from the disorders of thought tempo (such as slowed or accelerated thinking), because the problem is not speed but an abrupt interruption.
Also known as
- Sperrung
- The German term sometimes used for the same phenomenon, literally meaning 'blocking' or 'barrier'.
Recognition features
- An abrupt stop in speech, often mid-sentence, with no obvious external distraction to explain it
- The person typically reports a subjective experience of their mind 'going blank'
- After the block, the person is usually unable to recall or reconstruct what they had been about to say
- May be followed by a change of topic once speech resumes, rather than a resumption of the original sentence
Eliciting it at interview
- Observe rather than only ask: note any sudden silences during the interview and, when one occurs, ask gently what just happened
- Ask directly: "Does your mind ever just go blank in the middle of a thought, so that you lose what you were saying?"
- Distinguish this from ordinary distraction by asking whether the person can usually tell you what interrupted them; in true thought blocking, they typically cannot
Distinguishing features
- Differs from simple distractibility, where the person can usually identify what pulled their attention away
- Differs from thought withdrawal, a delusional experience in which the person believes an outside force has actively removed the thought, rather than simply experiencing a gap
- Differs from word-finding difficulty (where the general idea is intact but a specific word is elusive), since in thought blocking the whole thread of thought is lost, not just a word
Common misconceptions
- That any pause in speech is thought blocking; ordinary hesitation, tiredness, and searching for the right word are all far more common explanations
- That thought blocking always indicates schizophrenia; brief blank spells can occur in severe anxiety, exhaustion, and some organic states as well
Related phenomena
Inhibition (Slowing) of Thinking · Thought Withdrawal · Obstruction (Blocking)
Diagnostically relevant to
Schizophrenia (links open the DSM-5 Learning Lab)
Practice this
A 27-year-old man is mid-sentence describing his week when he suddenly stops, stares blankly for a few seconds, and says he has completely lost his train of thought and cannot recall what he was about to say. There was no obvious distraction. He says this has been happening several times a day for the past two weeks. What is this? · A 24-year-old woman describes stopping mid-conversation multiple times a day, each time completely losing the thread of what she was saying, with no recollection afterward of her original point. She denies any sense that someone or something is removing her thoughts — she says it 'just goes blank.' Before revealing the answer: what is the finding here, and what detail in her account would make you suspicious this was thought withdrawal instead? · A patient's train of thought or speech is repeatedly interrupted. Before revealing the answer, decide what distinguishes distractibility from thought blocking. · A patient's thinking seems disrupted. Before revealing the answer, decide what distinguishes inhibition of thinking from thought blocking. · A patient stops speaking abruptly mid-sentence and cannot say what they were about to say. Before revealing the answer, decide: what single question would tell you whether this is thought blocking or thought withdrawal? · You're conducting a mental state examination and want to check specifically for thought blocking, not just note it if it happens to occur unprompted. Before revealing the answer, decide what you would actually say and do. · In your own words, explain why thought blocking is classified as a disorder of the continuity of thought rather than a disorder of thought tempo. Think it through before revealing the model answer.
Illustration
During the interview, a 27-year-old man is describing his week when he stops abruptly halfway through a sentence, stares blankly for a few seconds, and then says, "Sorry — I've lost it completely. I don't even know what I was talking about." When asked if this happens often, he says it has been happening several times a day for the past fortnight and that it makes him reluctant to speak in front of colleagues.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 4, 'Disorders of Thought and Speech'.