Nathan Peiffer-Smadja, an infectious disease specialist at the Bichat-Claude Bernard Hospital in Paris, who has coordinated research on monkeypox patients, said the "psychological distress is linked to several aspects" of the disease.
Monkeypox can be very painful, particularly due to lesions which commonly appear on intimate areas or the face.
The "after-effects, particularly aesthetic", are distressing for many who fear they could be left with long-lasting scars, Peiffer-Smadja said.
A small number of patients can develop internal lesions which can be "extremely painful", Peiffer-Smadja said.
"You do not come out unscathed from a disease that has hurt you so much... as well as the additional burden of discrimination," said Corentin Hennebert, one of the first cases in France.
That was unfortunately the cases for Hennebert.
"I constantly had the impression that razor blades were being thrust into me -- I can't think of any other comparison, (the pain) was so strong," the 27-year-old told AFP.
"All I could think about was the pain," he said.
"And I'm not the only one, others have contacted me to tell that they were at the end of their tether, that they were crying all the time."
After recovering, Hennebert went on to become the spokesman for a group of monkeypox patients demanding swifter action against the disease.
The global monkeypox outbreak has "reawakened the trauma of HIV" despite the disease being far less deadly, said Nicolas Derche of the French LGBT group SOS.
"For HIV-positive people, this has revived some very rough things," from fear of a diagnosis to reliving past discrimination, said Vincent Leclercq of the French group AIDES.
Tuller said he received a torrent of insults and derogatory comments when he went public about having monkeypox.
"There is a lot of residual homophobia and this has a real impact on mental health," he said.
"Many don't say they have -- or have had -- monkeypox, fearing being stigmatized," he added.
Young people who have not yet come out are put in a particularly difficult position, as are those afraid of having their sexual orientation revealed to their employer because they have to isolate for three weeks, he said.
Nearly a quarter of the calls to a French monkeypox helpline this month were about psychological issues, the group that manages the line told AFP.
Some gay men have avoided any sexual activity for months out of fear of the disease, further impacting mental health, LGBT groups said.
