Do mental health professionals -- psychologists & psychiatrists -- find Myers-Briggs to be a useful way of categorizing people?

Categorizing people for theoretical purposes and research may hold value, but for practical purposes I have not found the need throughout the years to determine personality type in order to provide mental health counseling. The core issue leading to the dysfunction of the individual or system takes priority in the therapeutic process.  Personality traits are certainly a part of the equation, but the answer to your query at least from my perspective is no.  Testing is a tool which may or may not have useful value depending on the individual taking the test, the motivation of the individual to provide honest answers, the ability of the individual to comprehend the test questions (educational level), the environment of the individual's past and current circumstances (future circumstances to a lessor degree), the culture of the individual, what the test is intended to measure, etc.  Validity and reliability of psychological testing is the cornerstone of the value of the test. Generally, I am not in favor of categorizing people as it can easily lead to faulty assumptions.  Treating the individual in front of you and not a label is good practice.  Remember people may have similar personality traits, but respond to any given situation in a variety of different ways.  Each person is uniquely different.  Keeping this in mind is helpful to the process.    http://www.jas-building-blocks-counseling.com/

I never used the MBT in a clinical setting. I also never saw a colleague use it, nor do I remember ever seeing the MBT in anyone’s clinical records. The last time I encountered the MBT was in graduate school where it was used for class resaerch projects. There are many other tests or inventories more geared towards symptoms and or clinical diagnosis. I do not think that what the MBT measures is that relevant for the diagnosis and treatment of mental illness.

MBTI is a fun tool but it isn't gospel in reading people. It only tells you what your preferences are but not how you will behave in certain situations. A far better tool for that is called the DiSC or Personal Profile System markets through Wiley, Inc. It profiles  4 aspects and describes what to expect when the individual is under pressure, what kind of team player they are, whether they can follow through on a task, and leadership potential. 

MBTI is not pseudoscience but it is also a test of normal personality functioning and therefore not the most helpful in dealing with troubled people. The MBTI is based on the work of CG Jung and his normal theory of personality which varies quite a bit from person to persson. Jung said some people are more intuative while others are more sensation focused and some rely on feelings more than thinking when a decision must be made. The other two scales, introversion-extroversion are useful in determing how a person recharges not how they behave with others, and if they tend to be planners vs more spontaneous. I have never used a MBTI when assessing a client. But I find the MBTI a useful way to think about personality apart from pathology.

I cannot speak for everyone, but I’d have to say no. The “Myers-Briggs” would br thought of as a psychological personality test. As such it is expected to test what it purports (it does not), but more importantly it must be reliable (it is not). The reliability factor is the most crucial (I know that seems anti-intuative, but I can assure you that reliability is the key feature of any measurement system or test).

At one time I was certified to administer the MBTI. At first I thought it was very interesting and I thought (still think) it was (is) useful knowledge.But try an experiment sometime: after you’ve recorded results and ‘determined’ a person’s personality, give them a ‘different’ personality than the one they ‘obtained’. There are often many ‘personalities’ that they will agree are ‘just like them’.Although I doubt that I, as an Introvert, could ever accept being labelled as an Extrovert.