Slightly off topic - but I adore the amazing way that animals (particularly dogs) can improve a persons mental state.
I am a youth worker in a locked residential facility with Child Protection, so the kids I work with are really messed up from abuse and neglect. By the time we see them, they often are showing abusive traits themselves. It's all trauma. These kids are completely ignored by society, and are dismissed as too damaged and too hard.
And then I bring my dog in if the clients are suitable and my dog will be safe, and these young people completely revert back to being wonderful and compassionate kids. These kids will spit in your face and try to choke you out if you're late with their hot chocolate, but as soon as a dog is in the building, the attitude shifts. My dog doesn't like loud noises, so they all try really hard to not slam doors. They take turns patting him (which he loves) and playing with him outside. These kids show a level of empathy and love that they often can't otherwise access. It's a perfect litmus test to see how the kid is operating.