An abrupt interruption of ongoing thought with a sudden restart.

• A. Blocking
• B. Derailment
• C. Flight of ideas
• D. Thought content

Answer: (A)

Blocking is an abrupt interruption of ongoing thought with a sudden restart. In the mental status exam, you’ll notice the speaker mid-sentence who stops unexpectedly and then resumes after a pause, sometimes without recalling what was being said. This reflects a disruption in the flow of thought rather than a failure of memory or knowledge, and it can appear in conditions that affect thought processes, such as certain psychotic disorders or catatonia.

Derailment differs because speech wanders to unrelated topics and the train of thought becomes loosely connected rather than stopping abruptly. Flight of ideas involves rapid, pressured speech with quick shifts from one idea to another. Thought content, on the other hand, is about what the person is thinking (delusions, obsessions) rather than how their thoughts are formed or interrupted.