If something breaks down, it falls apart or stops working. In this case, Schizophrenics have a thought process that doesn’t work. What wikipedia article you quoted on Wikipedia is posted on Wikipedia.org (external link only) ( org/wiki/Schizophrenia) continues “Common symptoms are delusions and disorganized thinking including auditory hallucinations, paranoia, bizarre delusions, disorganized speech…” This symptoms are examples of the breakdown mentioned.

Help http://www.thefreedictionary.com/us/default.asp.x?page=1 com/breakdown :1.

  a. 2. b. 3. e. ds are the act or process of failing to function or continue? The condition resulting from this: a breakdown in communication. 1. Do I have to change this step for the future? Electricity The abrupt failure of an insulator or insulating medium to restrict the flow of current. A typical sudden collapse in physical or mental health. 4. Analyse, outline, or summary consisting of itemized data or essentials. 5. All the other terms will be used. What is the process of decomposition? Are these very loud energetic British Country dancing styles?  

Your list is an example of definition 3.

Your quote is an example of definition 4.