Final answer:
A person with an apparent mental disorder can be taken into custody under the Mental Health Act without committing a crime or being physically violent. The criteria for detention generally involve assessing the person's risk to themselves or others based on their behavior and statements.
Step-by-step explanation:
Under the Mental Health Act, a person with an apparent mental disorder can be taken into custody by the police even if they haven't committed a crime or been physically violent. The criteria for detaining someone under the act may vary depending on the jurisdiction, but generally, it requires that the person poses a risk to themselves or others due to their mental condition. This risk can be assessed based on the individual's behavior, statements, and the advice of mental health professionals.