Lawyers defend many genuine criminals who, after being freed, would go on to continue to commit terrible criminal acts. I would imagine that it is a profession that is extremely taxing on one's mental health.
That being said, I assume that Larry the lawyer, after successfully defending someone, can't just go to his therapist Theodore and blab "I feel like I just let a murderer go", no matter how important it is for Larry's mental health.
Mental health is important for all people in any profession. But are lawyers, who deal with some of the darkest parts of society, discouraged/dis-allowed from interacting with therapists? Even if Larry the lawyer tries to obfuscate the details (e.g. "I have a friend who just defended a murderer"), it's pretty clearly something that's bound to break attorney-client privilege. So I'm not sure what the answer might be.
Edit: upon further reflection, this question may be generalized to "borderline breaking NDA by opening up to your therapist". The therapist is obliged to keep things confidential, and their therapy can be considered a medical necessity just like a neurosurgeon's (depending on whom you ask). So I suppose the crux of the problem is whether opening up to a therapist (which can be a medical need) constitutes a breach of secrecy.