Re: Let's not jump to conclusions
"He might have threatened self harm in the past, so they may want to psychologically assess him"
The correct term is 'psychiatrically assess him'. Psychologists participate in MDT assessments, but their expertise is not psychiatry per se. The people who bear the greatest brunt are the two doctors required for non court sectioning and the approved social worker in psychiatry (yes, only one). However psychologists cannot and do not issue psychiatric diagnoses, only psychiatrists can do this.
The difference between psychiatrists and psychologists; the former go to med school and then choose a specialised branch of medicine, psychiatry, and further specialise in, e.g., forensic, geriatric, psychoses, eating disorders, anxiety disorders, and so on. The latter read a B.Sc. in psychology and then choose to specialise and move on to an approved doctorate in clinical psychology, in which they choose a further sub specialisation in, e.g., psycho geriatric, psychoses, etcetera. Not all psychology courses result in doctorates, and the doctorate in question is a doctorate in clinical psychology. (Psychology has become Americanised, I regret to say.) Other branches in psychology include organisational, occupational, forensic, counselling.
The emphasis in psychology is on science, whereas in psychiatry the emphasis is on medical practitioner training in psychiatry, akin to an art or a craft.
Psychiatrists prescribe medicines, psychologists do not although some twits occasionally argue in favour of this. I don't know about you but I'd like my prescribing officer to be well versed in anatomy, drug interactions and life saving, not in psychometrics, scientific testing and how-does-it-feel crap. That way there's a tendency for the patient to live a little longer.