The suicide rate always dips after wars, at least historical wars. Wars, again speaking historically. reduced the male population. After the war, surviving males easily find mates and settle into stable homes, resulting in baby booms. It doesn't take much. A change of a few percentage points can radically change the dating scene.
I have read about this trend in smaller societies. It has been implicated in the 80s/90s aids crisis in US black communities. A substantial percentage of 20-30yo black males were jailed during the drug war. Those males not in jail found dating far easier. Females had to compete for the artificially reduced number of males. This lead to reduced condom use, accelerating the heterosexual spread of aids in these communities. Also, a baby boom. Changing the male/female ratio in an extremely powerful driver of change.
I think what you're referring to may be different. If you look at the data in the initial graph, suicide rate increases after both WW1 and WW2. It actually went down __during__ the wars and not after, which falls more in line with Junger's book.
I have read about this trend in smaller societies. It has been implicated in the 80s/90s aids crisis in US black communities. A substantial percentage of 20-30yo black males were jailed during the drug war. Those males not in jail found dating far easier. Females had to compete for the artificially reduced number of males. This lead to reduced condom use, accelerating the heterosexual spread of aids in these communities. Also, a baby boom. Changing the male/female ratio in an extremely powerful driver of change.