Honestly why would a shrink care? "Hey doctor, I considered doing this thing once and decided it was a bad idea." "Yep, that would have been horrible -- good job!"

I mean seriously, are we so constrained by society that we aren't even allowed to consider things? I guarantee I am not the only decent person who has considered that I could take a life and decided against it. It's probably a daily occurrence in some fields.

Should have included this in my comment: https://www.buzzfeed.com/rosalindadams/intake

But basically, your interests are not necessarily aligned with your doctor's interests. If they are trying to find grounds you are a risk to yourself or others, then such statement can be taken as such.

There's a radiolab episode (not the best source, but not the worst either) about how most people seriously consider murder at least once in their life.

When you get so far as to consider how you'd get rid of the body, you've probably gone a step past "most people".

In many jurisdictions, things you say to your shrink are privileged information, if I'm not mistaken.

Assuming someone is on your side when they are not is a huge mistake. In one case people are being committed in large numbers basically for insurance fraud. https://www.buzzfeed.com/rosalindadams/intake

I'm sure there are exceptions for things like "I'm thinking about killing someone".