Answer:
The answer is OCPD (obssessive-compulsive personality disorder).
Explanation:
A person who suffers from OCPD has unwanted, repeated thoughts that drive them to carry out an action (compulsion). The insisting of Monk about following a rigid order is an example of his compulsion.
People wth OCPD might show themlseves as reserved and absent-minded. This a result of their obssesive thoughts, which occupy their minds most of the time.
