Nice thread...I am biased though
To add my 2 cents here.
I have suffered and been treated with severe Generalized Anxiety Disorder for 12 years. I have also studied psychology.
There is no single indicator in any chart I have looked at that shows anxiety disorder because there is no single cause but a combination of organic dysfunction and external influences + coping mechanism state. Schizophrenia for example would be a different story and I would expect involvement of harsh set-up within 1st house with 12th and weakness in 6th. Genetic predisposition can likely also be traced to either the maternal or paternal line. I have not yet bothered with it but will do eventually.
Anxiety tends to focus on various fields. Examples:
Generally, Social anxiety/agoraphobia will be seen from tendency towards self-confinement (obviously focus on 12th, Perhaps afflicted Moon or notable placements in 2nd/4th, notable placements in 4th). This is again different to generalized anxiety.
Health anxiety tendency should be seen from at least one poor Virgo placement.
Mercury will show basic coping skills and ability to come to grips with other mechanisms as well as tendency to go overboard mentally and is in my opinion the most important planet to look at for anxiety issues.
Outer planets will point to areas where triggers lie. Uranus applying negatively tends to cause a general unease with unpredictability of life and I have seen it as a trigger in quite a few charts so far.
Further if Pluto is afflicted it will show a sense of powerlessness and fear of losing control. Very common sensation for most anxiety sufferers.
Neptune contacts will indicate whether or not the person is likely to opt for or accept medication and how smoothly treatment would flow. Neptune trine the activating planet/s will generally indicate easy treatment and likelihood of positive outcomes.
Unhelpful Neptune contacts (or prior to engaging with or channelling Neptune energy at start of condition) may add a dimension of derealisation/depersonalization to the anxiety response that is another common complaint of patients/manifestations of the condition as it advances and the system starts to reach breaking-point. What we call a mental collapse/breakdown is usually an overdose of Neptune energy spacing us out as a protective internal mechanism. Poor Lunar placement can turn this into an emotional breakdown or neuropathies for example (excessive crying, tormenting dreams, etc)
It is very complex. It is a several-fold reaction that triggers adrenal over-response and therefore anxiety is just a manifestation of various tensions that usually involve a large portion of the chart and are not localized. When they are localized they are more likely to manifest as sporadic panic episodes or perhaps phobias. Further, anxiety tends to progress and may also offshoot in several directions including social imbalances, agoraphobia, OCD (coping mechanism actually not a disease as such), transient psychotic episodes (NOT schizophrenia) and so on. Untreated anxiety quickly overtakes various energy fields. Breaking up the issues into small digestible pieces can be helpful for someone actively seeking to address various outcomes of their mental tension.
Sending love to anyone looking to come to grips with their anxiety or depressive disorders.