Scale for the Assessment of Thought, Language and Communication (TLC)

Nancy C. Andreasen · 1986

Andreasen's glossary of operationally defined disorders of thought, language, and communication, rated from interview speech.

The TLC reconceptualizes formal thought disorder as a set of observable disorders of thought, language, and communication, each given an operational definition and verbatim examples. It is the canonical span-annotation instrument for disorganized speech: every item corresponds to an identifiable utterance type an annotator (or an agent) can highlight and label.

This scale covers the core, pathologically significant items. Each item is rated for frequency/severity over the interview sample (scaled proportionally for shorter samples). Some items overlap closely — see each domain's Contrastive Learning section for how to choose between neighbours (e.g. Circumstantiality vs Loss of Goal, Tangentiality vs Derailment).

Domains (12)

DerailmentDER

Ideas slip off track onto obliquely related or unrelated topics, without the speaker noticing.

—Curated skill
TangentialityTAN

Replying to a question in an oblique or irrelevant manner; the question is never answered.

—Curated skill
CircumstantialityCIR

Very indirect, delayed reaching of the goal idea, with tedious detail — but the point is eventually made.

—Curated skill
Poverty of SpeechPOS

Restriction in the amount of spontaneous speech; brief, unelaborated replies.

—Curated skill
ClangingCLA

Sound rather than meaning governs word choice (rhyming, punning).

—Curated skill
Poverty of Content of SpeechPOC

Adequate amount of speech that conveys little information; vague, repetitive, empty.

—Curated skill
Pressure of SpeechPRS

Increased, rapid speech that is hard to interrupt.

—Curated skill
Distractible SpeechDST

Stopping mid-sentence and changing topic in response to a nearby stimulus.

—Curated skill
IllogicalityILL

Conclusions that do not follow logically — non-sequiturs and faulty inferences.

—Curated skill
NeologismsNEO

Completely new word formations whose derivation cannot be understood.

—Curated skill
PerseverationPER

Persistent, inappropriate repetition of words, ideas, or subjects.

—Curated skill
Loss of GoalLOG

Failure to follow a chain of thought to its natural conclusion; the point is never reached.

—Curated skill
Andreasen NC. The Scale for the Assessment of Thought, Language, and Communication (TLC). Schizophr Bull. 1986;12(3):473-482. doi:10.1093/schbul/12.3.473

Item definitions are freely reproduced from the open-access Schizophrenia Bulletin article; operational wording here is grounded in Andreasen (1986). Cite Andreasen.