This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Symptoms & Signs , Subject name: Psychiatry
Delusion is a disorder of - 
Select and explain. 
A. Thought, B. Perception, C. Affect, D. Emotions
A: Thought
Answer: A: Thought 
Explanation: Ans. is 'a' i.e., Thought Thought disordersFormal thought disorders (Disorders of thought process)Disorders of thought contenti) . Racing thoughts :- Anxiety, Schizophreniaii) Retarded thoughts :- Depressioniii) Circumstantiality :- Mania, Schizophreniaiv) Thought blocking :- Schizophrenia, Severe anxietyv) Perseveration :- Organic brain disease, Schizophrenia (occasionally)vi) Loosening of association : - Schizophreniavii) Flight of ideas :- Maniaviii) Tangentialityix) Clunging & punning :- Mania & schizophreniax) Neologism, word salad, Echolalia :- Schizophreniai) Delusion :- Psychosis (Schizophrenia, mania, depression & othersii) Obsessioniii) Compulsioniv) Preoccupationsv) Phobiasvi) Depersonalization & Derealizationo In schizophrenia and mood disorders (depression, mania) all parts of the thought (thought process as well as content) are involved.o However, schizophrenia is conventionally referred as formal thought disorder.