Suicide, like any form of death, seems most often to be a very personal decision. Unlike many death situations, however, suicide tends to involve another person in the role of "being the reason" why death is the solution. Still, this is in the individuals mind.
I would think that many "standard" or "typical" suicide signatures would be found to be invalid in most cases due to this personal approach to life and death.
For instance, Alan Turing, the brilliant English mathematician who broke the German Enigma code during WW II, had no significant transits to his natal chart's angles and only a t/Venus squaring his natal Moon at the South Node. Nobody would predict suicide from this pattern alone.
However, when we utilize other cyclic charts as well as taking into account the context of the subject's life we may be able to see possible suicide in a chart. Again, using Turings chart as a singular example, a Sidereal Progressed Solar Return (actually cast as a precession corrected Tropical Return) advanced to his June 7, 1954 date of suicide shows us that:
1) t/Sun was opposing his daily/advanced Ascendant. The Sun (vitality, sense of purpose, decisions) was at the ancient death angle, the 7th house cusp.
2) n/Moon near the daily MC was squaring t/Venus. Venus is often found in cyclic death charts as indicating a "balancing" factor, resolving conflicts.
3) n/Pluto conjoins n/Venus, making this pair a "fated" trigger that can be activated in cyclic charts. We have seen that n/Venus' counterpart, t/Venus has played its role. If we look at n/Pluto's counterpart, we find t/Pluto at 22 Leo where it combines with the daily Asc. at 18 Sag to make the MC the midpoint of Asc/Pluto. This changes the MC as a personal status/goal/public image factor into a pressure point of how to act to resolve his "problem." His problem was that he was a homosexual in post-war British society which was being racked by sexual scandals in the Intelligence community and its cold war against the Soviets. He had been "found out" two years earlier and stripped of his security clearance, work, and purpose in life. All this relates to the CONTEXT OF LIFE that I had referred to earlier.
If we turn to another favorite form of cyclic charting that I use, t/Moon-to-n/Sun Returns we find more telling indications of problems for Alan Turning:
4) the June 2nd, 1954 t/Moon-to-n/Sun occurred in the 9th house, indicating (citing my next-year's book interpretation for this) offers three interpretive statements to fit an individual's life context. The third context-sensitive statement is "Leaving or avoiding a place or situation that one detests."
5) This t/Moon-to-n/Sun Return has t/Neptune on the Ascendant, squaring n/Neptune. This is a confusing and highly idealistic period for Turing. How could his vision for what is life's work was producing be so "disolved" in front of him? (He had been developing the basic tools for today's modern computers, for which he has been recognized).
6) His natal MC-Uranus combination is at the IC of this return chart. His work and status in life was at and end and had to find a new beginning. t/Mercury, t/Jupiter, t/Moon were at the MC. Where was his mental-work, his opportunity, his public acceptance? It had all been taken from him due to his homosexuality.
If we advance this chart, just as we advance Dirunal charts, to June 7th, we find:
7) n/Asc. in the 8th house of sex, death and taxes, squared by t/Moon from the 11th house of future and friends. He perceived himself as having no friends and no future if we remember the CONTEXT OF HIS LIFE.
8) t/Part of Fortune (so important when dealing with sun-moon charts) tells us how the Ascendant might "act" to express itself. t/PoF opposes t/Uranus in the 9th house where the Moon-to-Sun return occurred. t/PoF also opposes n/Neptune, more confusion is added to the mental mix. It would seem that a sudden decision was made.
9) The chart's Asc. is bracketed closely by t/Saturn and t/Neptune. Societies rules need to be dissolved so as to be free of them.
These are limited examples of how cyclic charts work when placed within the context of the subject's life. I hope they spark some interest and recognition that simple astrology with just a natal chart alone doesn't help one to fully understand events that shape our life. My blog site at http://www.ninthhouse.wordpress.com/
offers several years of such posting using cyclic charts. Dave