Whoa, that is an interesting question. I would say as SLPs we need to be very careful in addressing language behaviors in psych populations.

Many psychiatric disorders have aberrant-sounding language behaviors, and I've received plenty of referrals for psych patients because of their strange talking patterns. Many times, though, what motivates the "speech problem" is a psychological issue, not a speech-language deficit. For example, OCD patients with compulsive verbal behaviors. The form of the symptom is speech-language, but that does not mean the patient needs speech-language intervention. ]

For example, when I worked at a SNF, I'd often get referrals for patients who were "minimally verbal" and needed help with "expressive language". Often times, these patients had depression. They weren't talking because they were depressed! It would be unethical to do speech therapy for expressive language on these people.

It's trickier when it comes to communication issues related to executive function. I've worked with a lot of bipolar patients who have benefitted tremendously from traditional speech-language therapy for skills like organization and sequencing. However, any psychiatric issues need to be well-managed and treated for SLP intervention to be effective. Executive function therapy requires at least some level of self-awareness, which requires a certain psychological or symptom management baseline.

It can be beneficial, but should be approached with very careful diagnostic considerations.