Pubmed has a study up which apparently was published in 2013.

Anyway, as you might already know, bdsm practitioners have, on average, better mental health than the general population. Of course, if you say this, then someone might challenge the meaning of the phrase "better mental health."

So, to break things down a bit, bdsm practitioners are more extraverted than the general population and they also have less neurosis and less neuroses, on average. In psych, neurosis is a category of mental disorder but one which is less of serious degree than psychosis. (Psychosis would mean the loss of touch with reality, delusions, hallucinations and schizophrenia. The psych doctors even create different gradations of schizotypy and schizophrenia, so that there is schizophrenia and schizotypal, depending on the severity or treatment conditions, etc.)

Things that are common and considered in the category of neuroses would be anxiety, depression, phobias and panic attacks. Bdsm practitioners have less tendency to neurosis (anxiety, depression, phobias and panic attacks) than the general population.

Bdsm practitioners are also more extraverted and have greater subjective well-being. Extraversion is associated with or causes greater personal happiness.

Extraversion is a different word with a different meaning that extroversion.