Yes offcourse... this question is bit tricy to answer..  But knowing the neural substartes alone might not help, it will help  in one aspect, that knowing the pathology and to help the patients in terms of diagnostics. But when you are keen in treating or managing the disorder... One has to look at all available options for treating or managing a psychiatry/mental disability. Including the holistic approaches that are done using traditional knowledge, which is beyond scientific proof.... how the mind and body work together.. is again a puzzle, in which there are evidence of improvement but if you ask how... it remains a puzzle....

I think it will. However, not so much for diagnostics. Current diagnoses of mental disorders are based on behavioral observations. Probably a group of, say, MDD patients have varying underlying disorders in neural substrates. So the aim should not be to improve diagnostics (how could you improve this when a diagnosis is based on behavior?), but more in prognostics, that is treatment outcome. This doesn't necessarily has to be related to a diagnosis.

I think that there is indeed a great deal of potential for a "revolution," but that what has held back the field back is the decidedly non-biological approach that has traditionally characterized psychiatric genetics, neuroscience, and related fields.  That is, the object of study is biological, but the approach and assumptions are not (or only so in a very limited way).  That is, there has been a general lack of anything resembling a systems or organismic approach when it comes to matters of the mind.  Brains nonetheless don't exist in vacuums (or vats) and will never be understood purely in reference to themselves and the occasional stimulus that impinges upon some sensory organ.  Zing Yang Kuo and Jaques Le Magnen are notable, past critics of the mainstream, dualistic (and reductionistic) approach.  For recent reviews hammering on this issue in the domain of depression, read:

http://journal.frontiersin.org/Journal/10.3389/fpsyg.2014.01580/full

http://www.ncbi.nlm.nih.gov/pubmed/25365763

Advances in Neurobiology,especially forDepression, haven't so far contributed as expected, but neverthelss they haven't been minimal. Understanding neural mechanisms has contributed to the better management to specific symptoms, e.g. cognition, apathy, residual symptoms in depression or cognition in Schizophrenia. Understanding and researching also  other than the classical neural mechanisms in mental disorders,  e.g. glutamate or HPA axis mechanisms  will give light to new psychopharmacological agents. Worth trying

Firsty, I option for the broadest understanding possible as regards to the symptoms and their causes, as diagnosed by the specialty doctors. The reasons that may cause neuropsychiatric disorders vary. Depending on the nature of both the causes and symptoms the milder the treatment the more valid the diagnosis is. As it often happens, a number of autoimmune diseases can also cause neurological disorders , which in their turn are difficult to assess and therefore diagnose.

Therefore, determining factors should be taken into account when considering individual symptoms. Recent studies have shown that systematic and controlled exercise has a positive effect on people with neuropsychiatric disorders. A search on “Exercise and psychiatric disorders” should help you.

This will be left-of-field for you all I think but I am going to give it a whirl anyway. I think the key to understanding a good deal of issues to do with mind health are likely to be bound up with perceptual structure. If it isn't functioning then our interaction with others and how we see ourselves will be affected. So what is perceptual structure? This is the left-of-field bit but stay with me. 

We have developed a new form of illusionary space. We term this Vision-Space as opposed to picture space (optical projection and the geometry of central perspective etc). Vision-Space is structured according to the data-sets and processes of information display that take place within the phenomenon of vision. It's by understanding all of that we get some key insights into perceptual structure. Experiential reality occurs through the operations of this perceptual structure.

Vision has nothing to do with the projection of optics! It's closer to a controlled hallucination. We generate it. I am not going to go into all of that here, if you are interested to know more there are some online presentation links attached and there are articles on my RG page. 

What I do want to get across is that the phenomenon of vision appears to be a construct where the key data-formation is a field structure provisioning an 'implicit' form of spatial awareness that we can address holistically. It's responsible for our 'presentation' of vision and 'time now' awareness. No re-presentation involved in this form of awareness. This structure is incorrectly termed as peripheral vision. It's Dorsal stream, 'where characterisation' and sub-conscious in nature. This is totally distinct from our 'explicit' take on reality that manifests within the field structure (not integrated) provisioning our contemplation of form and conscious awareness, abstracted from 'time now'. Very different computational processes involved in each.

Mind has to deal with both takes on reality to form our sense of where we are and what we are attending to. This is what's involved in us being objective. If this complex pathway processing and composition within phenomenal field with respect to our intent in the world is not performed correctly for what ever reason we will struggle to orientate and communicate. Our perceptual structure will be essentially atypical. 

We generate vision as biological systems. If it's not functioning correctly the result will be chemical imbalances, neural redundancy and feelings of alienation etc. To which voice, which take on reality does the mind align itself to most? The article attached is an attempt to extrapolate these relationships onto cultural development. So nothing too theoretical and over expansive!

Does any of this contribute in any way?

If my "depressive thinking" can affect my neural activity (as some research indicates), then looking at the neural activity in such a case is not as helpful as straightening out my thinking.

I've found so many "biological causes" of depression that are almost unrecognized as causes (e.g., influenza, Cushing's, etc), that one gets disheartened. In the 80s, I had many doctors question me why I thought hypothyroidism could be a cause. Fortunately, that is accepted pretty much nowadays. When I worked in a psychiatric hospital, the doctors were surprised that B-12 deficiency could mimic schizophrenia and senility...until they saw the miracles of B-12. I still find doctors not checking for some simple, biological causes of mental problems.

Dave