Yes, it is a thing. I believe it is partly caused by unrealistic expectations. Fantasy and reality have collided. The difference between those expectations and reality create a very real stress and may even lead to depression.
It is a crash in the “high” of adopting (basically the excitement is over), the dopamine is no longer being released. The sad fact is that the adoptive parent finds they still have the same emptiness troubling them that drove them to adopt to begin with.
Life had been a flurry of emotions during the adoption journey: hope, relief, frustration, waiting, excitement, and not to mention adding another person to one’s family. Not having the hormone fluctuations related to birth does not mean that the adoptive parent won’t have their own share of emotional fluctuation.
Of course, new parents of both genders have emotional reactions to 1) sleep deprivation 2) new roles and 3) reconfiguration of daily life, but having this is not the same as hormone induced postpartum depression that a delivering mother experiences.
So, with a newborn, sleep deprivation can certainly be a factor. If an older child was adopted, then the reality of a traumatized child may be very different than the idealistic vision hopeful adoptive parents expected.
An adoptive parent may even grieve for the child who is now in their own home, who they may love desperately, only to find that child dreams of his original mother coming back to reclaim him. An adoptive mother can never replace the original one.
So a couple does CHOOSE to adopt. If those circumstances turn out to be hard to live, like any biological parent, they need to deal directly with it. If it’s all NOT what the adoptive parents expected, they should seek help and learn to deal with the reality. That’s parenting and adoptive parents have signed up for it voluntarily.
Depression sucks regardless of what it’s caused by. Affected parents need to seek help, see a trauma informed therapist, seek out specific resources, get on anti depressants if necessary – but NEVER just throw away a child.