... among their sample of 87 participants, gay and bisexual men actually had a slightly lesser chance of depression and anxiety, along with lower stress levels (as indicated by cortisol and 20 other biomarkers) than heterosexual men. Perhaps most significant, though, was the secondary finding that they hadn’t even been searching for: In their study, lesbian, gay and bisexual individuals all tended to have lower stress levels and a smaller chance of depressive symptoms if they’d come out to friends and family than those who’d kept their sexual orientation a secret.
... within the group of 46 lesbian, gay or bisexual participants, the 31 individuals who’d come out had noticeably lower cortisol levels than the 15 who hadn’t disclosed their orientation to others. Additionally, survey answers indicated that the first group had fewer symptoms of depression or anxiety than the other group. Admittedly, the study’s limited sample size means that these results can’t be interpreted as definitive, and further study is needed to confirm that they hold true on a widespread level.[emphasis mine]
Their sample was adults, not children or teens.
... the 31 individuals who’d come out had noticeably lower cortisol levels [and fewer symptoms of depression and anxiety] than the 15 who hadn’t disclosed their orientation to others.
The closet door isn't binary: some people are somewhere in between not being out to anyone, and being out to absolutely anybody and everybody. I wonder how the "degree of being out" correlates to lower stress and depression.
It's quite common to hear of the coming-out experience as being "a huge weight off my shoulders" or some similar phrase. I don't doubt for one New York minute that symptoms of depression and anxiety are lowered as a result of being open, honest and able to freely be yourself. People in denial or closeted about their true sexual nature are heavily burdened by society, family and religion, and that can be a terribly excruciating situation to be in.
I don't think it is the actual coming out that is good for your health. It is being the type of person who is willing to come out. Not being ashamed of who you are is good for your health.