How do strict parents tell spoiled behavior from serious disturbance in a child?

I'll give two examples of an 8-9 year-old child.

Whenever it's an older kid having a bad attitude, getting in trouble, stealing, etc many will simple say that kid is spoiled and needs discipline.

Now if that kid were well behaved at home, is ok at school but has been caught secretly laughing after hurting or killing an animal (ex: drowning a cat and smiling), then most people even traditional folks are quickly to comment "seek a professional right now". Some would even say that's beyond any type of discipline.

How do even stricter parents know the difference?

How do strict parents tell spoiled behavior from serious disturbance in a child?
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