In my opinion, suicide is an evolutionary trait design to unburden the group when the self is no longer felt to be of any worth; e.g. contributing positively. If this were true, then placing the suicidal individual in a completely different environment; one in which they might be more successful, might be therapeutic. For example, relocated to another country with a foster family. More easily said than done.
There is a problem with this theory: it hypothesizes a benefit to a group, but no benefit to the individual who commits suicide. Individuals who do not have the gene(s) that predispose toward committing suicide would therefore be more fit than individuals who do, and these gene(s) would never become widespread.
The article mentions this, tangentially - human beings are the only species (we know of) capable of empathy and theory of mind, the ability to put yourself in another's shoes. And one side effect of that is the ability to feel shame, to feel like you're a worthless individual because of your effect on the group, which in pathological situations can result in eliminating yourself from the gene pool. It's not that there's a gene for suicide, it's that there're genetically-based traits like empathy, ambition, and pain-tolerance that when combined with a hostile environment can result in suicide. (One of Aaron Swartz's traits commonly referenced in his eulogies was how unusually empathetic he was.)
It's very well-documented that there are some genes that can be adaptive in some situations and fatal in others. For example, sickle-cell anemia is highly adaptive in sub-Saharan Africa where it confers immunity to malaria, yet results in debilitating blood clots when expressed in some individuals. Suicide is the mental version of this: not a genetic trait in itself, but a side-effect of a collection of genetic traits that are usually beneficial in isolation.
"It hypothesizes a benefit to a group, but no benefit to the individual who commits suicide"
If you know you can't pass on your own genes, then the next best thing is to pass on the genes of your family or close relatives. Committing suicide may (or may not) make that more likely.
I don't think there is necessarily an evolutionary reason for suicide, but it certainly seems to fit within an evolutionary framework.
Genes which are harmful to individuals can indeed propagate if they are beneficial to the group. If a group that contains a gene is fitter than another which does not, a gene may propagate even if it is harmful to individuals in certain situations. Presumably this is how altruism, community, and patriotism evolved. Kids die in battle all the time, even with no close family members to protect; chalk it up to a gene for "duty."
Damn it, you can't just say that; there is math involved! On the one hand, you have the evolutionary cost to yourself: if you die, then you can't have any more children. On the other hand, you have the evolutionary benefit to your close kin: they have access to more resources with you gone. This benefit is weighted by how closely these other people are related to you. A rule of thumb is that you break even if you sacrifice your life to save the life of two siblings, four nephews/nieces, or eight cousins.
Do you really expect that a get-depressed-and-die instinct would reliably result in at least that much benefit to someone's close kin? If not, then you don't really expect such an instinct to evolve by kin selection.
>Do you really expect that a get-depressed-and-die instinct would reliably result in at least that much benefit to someone's close kin? If not, then you don't really expect such an instinct to evolve by kin selection.
Consider the case of cancer. Cells have builtin functions for commiting suicide when something goes awry, and also do not breed excessively normally. However since knocking those inhibitions out is advantageuos in the short term, cancer arises again and again. The mutations seems to confer an advantage, for the first generation, the second generation... quite a few generations actually. Then suddenly, as the cancer cells reach critical mass, and the parasite/parasitee ratio grows to large, it becomes a huge liability. The cancer cells die. Every single one. The end.
evolutionary cost to yourself: if you die, then you can't have any more children.
If we suppose that people only consider suicide in bad situations, where, say, their expected reproductive capability is maybe 1/8th that of their surviving relatives, then the evolutionary cost is 1/8th of what you assume. In this case, you would only need to save one cousin, or to have 1/4 of a chance of saving a sibling, or 1/2 a chance of saving a niece/nephew. Or maybe not "saving" a niece, but making it practical for your siblings to deliberately have another niece. ... The scenario remains questionable, and the 1/8 is of course made up, but it does seem possible.
If there exists such a thing as group selection. This is not entirely clear and many biologists remain unconvinced about that theory (Richard Dawkins most notably).
A lot of suicides are caused by self hatred. No matter where you go, there you are. Have you ever spoken to someone who moved because they were depressed? It rarely helps as much as actually seeking help, because the situation you're trying to escape isn't a social one, it's one in your mind. Depression is not a result of factors leading to suicidal ideas, depression is the factors leading to suicidal ideas.
Some of the most admired people are severely depressed and suicidal, people you would consider to be "contributing" and outstanding members of society. I must say, I don't think you have any clue what you are talking about and your "evolutionary" theory is just abominable and the relocation theory is childish. These feelings follow you wherever you go, relocating might temporarily give momentum but without proper help it is useless if we are talking suicide and severe depression.
