He is my nephew by marriage; and is not genetically related to me.
I do not know his sleep habits.
As for myself, as a lifelong chronic insomniac, I do, when I know I am not going to sleep, take the pharmaceutical isostere of melatonin myself, zolpidem, (ambien.) I have never found melatonin itself to be effective; but zolpidem is marginally effective, sometimes. I try to avoid zolpidem whenever possible, and sometimes will take OTC antihistamines formulated for sleep induction. They also work marginally. At the core however, I am an insomniac and nothing can change that, despite decades of advice.
My nephew definitely has a problem with depression, a severe problem, and there is definitely a genetic component, actually on both sides of his family, my wife's family and my former brother's-in-law family, where there does seem to be a history of psychological symptoms. My nephew's grandmother on his father's sde has been in and out of hospitals where she's been admitted for psychological disorders.
My mother-in-law was also on psychiatric meds her whole adult life. All three of my wife's sisters take antidepressants, including my nephew's mother, as does one of my nieces.
My wife, by contrast, has never evinced depression or psychotic disorders; one of my sons struggled a bit in high school, but he muscled through it by teaching himself neurophysiology apparently.
I do believe that genetics can and do influence mood disorders; although again, I'm not a genetic reductionist. I believe we have to work to handle our genes; not that our genes determine us.
My nephew's a very nice kid, generally, and he will talk freely with me about his state, but we live about 200 miles away and as an uncle, I'm not sure if or how I can help.
I don't think there's any kind of magic wand.
As far as "chicken and egg," though I'd go with egg. He's had problems for some time. His parents divorce did not help, even though the divorce was fairly civil.
The pot thing however is not helping; it's making things worse. It is definitely creating an inability to form stable friendships.
As for the root cause of his inability to do without pot - understanding the extreme unpopularity of this view here - it has the hallmarks to me of physiological addiction, and I'm not fond of the glib objections to this claim, particularly when they are rote and dismissive without even a shred of intellectual integrity, for instance calling the paper in the OP "garbage" without clearly offering a shred of specific evidence to support the claim. (This has happened elsewhere in this thread.)
I, of course, come from a generation in which pot was presented as some kind of wonderful and marvelous substance that was "good for people." I don't agree, and my lack of agreement does not stem from naivete. Overall, I think pot use is a negative.
(I live in a world dominated by molecular biology and my world view is very much connected to it.)
We have in the past, and do now, worry about my nephew's potential for suicide. He was smoking pot the last time he was hospitalized for a suicide watch, so I really don't want to hear that pot is keeping him from it. Right now insurance problems have him on a wait list for an evaluation.
I'm worried that his mother, my sister-in-law, is giving up on him. I understand it's hard on her, and again, I wish there was something, anything, I could do.
All this said, I don't think it's a problem that OTC substances can address, although I do thank you for your concern and advice.
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