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Moving to California may have been a "fight or flight" reaction to problems in Harry and Meghan's life, according to psychotherapists.
Both Prince Harry and Meghan Markle have been open about their mental health struggles in recent months, with Meghan sharing that she had suffered with suicidal thoughts when she was pregnant with her son Archie, who is now two.
Harry, 36, said the duchess, 39, was only kept from following through on the thoughts she was having because she was worried about causing more grief for the prince if he lost another woman in his life.
He said the couple tried for four years to make their situation work, before he moved them to the US for their mental health, and has said a couple of times that going to California wasn't their original plan.
Psychotherapists say that while moving can help create a shift in mindset, it might be a 'fight or flight' reaction to outside circumstances, and urge caution when making big decisions.
Psychotherapist Gin Lalli told Yahoo UK: "Big life changes doesn’t always ‘cure’ depression. You may be making that decision too reactively – using the fight or flight response.
"The changes may feel right at the time but you need to engage the more rational and objective part of your brain to do that and when you are depressed, you are far from there.
"Often, making a snap decision to make a huge life change, is a reactionary response when you are stressed. Your brain literally senses the danger level almost and kind of wants to ‘run away’ from the problem.
"It needs to take some action immediately but often that action is purely reacting to the moment and not considering the long term effects.
"On the other hand, knowing that certain things may need to change is useful. But implementing those changes too quickly and irrationally can create problems further down the line.
"So many people I know regret decisions made in 'the heat of the moment'."
Harry and Meghan have a slightly different situation because for the duchess there was an element of returning home. She said it was "good to be home" in some of her first interviews last summer, after buying a mansion in Santa Barbara with Harry.
Geraldine Joaquim, clinical hypnotherapist and psychotherapist told Yahoo UK: "For Meghan the move to the US was one back to familiarity, she must have felt completely at sea in the UK - not only a new country but entering into The Firm, with all its rigid structures and traditions.
"Whatever anyone thinks about her, without a doubt it would have been a culture shock. So her return to more familiar territory, moving out of the shadow and back into a world that includes her being able to work as well must have been a relief.
"And almost certainly brought about a huge shift in her mental health."
However, she added the situation is more complex for Harry because he was concerned about his wife and child, as well as future children, but there was additional "emotional baggage".
She said: "There’s also the shadow of his mother and her sad history hanging over him - one could argue that he’s living out her legacy, she had made great efforts to distance herself from the Royal Family, giving that very public interview with the now-discredited Martin Bashir, effectively creating a new identify and role for herself before her untimely death.
"So the move to the US for him is on the surface solving the immediate need to get clear of the strictures of living under the Royal Family - the mental health side is more complicated.
"However in many cases, action is the great enabler! Much of poor mental health lies in feeling stuck, unable to see the future, which causes a downward spiral.
"A change, whether it involves geographical relocation, a new job, a new activity, can offer a break from running on that same treadmill.
"A chance to disrupt the same negative thought patterns so you can create new ones, which feed into more positive mental health."
But she urged caution because "wherever you go, you take yourself with you", adding: "Some people may be able to discard an old life successfully and move on to a brighter future, others may not. A lot depends on mindset, resilience and perceptions of the old life and how much you can embrace the new."
Watch: Prince Harry in 'The Me You Can't See': the 3 most shocking revelations
Natasha Tiwari, an award-winning psychologist and psychotherapist who works with families, said: "Depression is really characterised by a persistent sadness, or lack of interest in life. A big life move or change has the potential to help, if that big life move addresses the root causes of the depressive state and mood, and injects some excitement about life.
"For many though, a big life change, like moving to a new country, may not be the antidote to depression.
"Such changes, for most people will come with a whole host of other pressures, for example, working out living arrangements in an unfamiliar place, and navigating a new geography without the camaraderie of friends and the love of support network close by.
"These have the potential to trigger low moods into becoming worse: with the added risk of anxiety and loneliness causing a potential deeper spiral of sadness.
"Harry and Meghan have the benefit of their positions supporting a much easier transition into a new social circle, new work arrangements, and of course each other's love and support.
"Combined with the move providing some distance from those who they say caused and exacerbated their depressive states, we can see why their big geographical move may have actually provided some real benefit to their mental health and general wellness."
In the most recent Apple TV+ special about mental health, Harry shared how he had learned to help Meghan cope with the suicidal thoughts she had.
He said: "I think it’s so interesting because so many people are afraid of being on the receiving end of that conversation (about suicide) because they don’t feel as though they have the right tools to be able to give the right advice, but what you’re saying is, you’re there.
"Listen, because listening and being part of that conversation is, without a doubt, the best first step that you can take."
In the main five-part series, called The Me You Can't See, Harry accused the Royal Family of "total neglect" and said he would not be "bullied into silence".
In the special he did not appear to directly reference family members, but did touch on the "shame" some families feel when someone struggles with their mental health.
He said: "As parents and as siblings there’s an element of shame that we feel because we’re like… 'How could we not have seen it? How did we not know? How did you not feel comfortable enough to come to me and share that with me?'
"But we all know that, when people are suffering or struggling, that we’re all incredibly good at covering it up."
Harry has long campaigned on mental health issues, starting from launching Heads Together alongside Prince William and Kate when he was still a senior royal.
It's likely to be a continuing part of his work now that he has founded Archewell with wife Meghan.
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