Present classification systems for thought disorder lack consistency and require one to remember long-winded definitions limiting their use to research settings. as an extension of recent work in this area (World Congress, 2008), we classify the characteristic thought disorder patterns seen in schizophrenia according to the location of the lesion in notional "threads" of mental computational processes that string speech together. These threads must take both semantics and syntax into consideration in performing their function. When we speak - just as when we write - there is a natural hierarchy topic thread (the topic of the ‘essay’) and multiples of paragraph threads, sentence threads, clause threads, word threads and phoneme threads. Intuitively, we grade the severity of thought disorder depending upon whether a particular thread gets stuck (S), reconnects abnormally (R) or is absent altogether:

1. I. paragraph thread R: Disjointed sentences S: Circumstantiality;

2. II. topic threadR: Tangentiality S: Preoccupatory thinking;

3. III. sentence threads R: Knight's move thinking S: Clause perseveration;

4. IV. clause threads R: Word salad S: Word perseveration, fusion;

5. V. word threads R: Incoherent sounds/ neologisms/ paraphasias S: Phoneme/syllable perseveration;

6. VI. phoneme threads - Failure of production: Mutism.

Of course, one must record all the lesions that are present at any given time. This scale incorporates a intuitive progression from mild to severe thought disorder in Schizophrenia. Using the STDS would allow the straightforward ‘bedside’ quantification of the severity of thought disorder and enforce discipline into the thought assessment section of the Mental State Examination.