algolagnia

thumb|Wartenberg wheel pain stimulation of the areola and nipple Algolagnia (; from , álgos, "pain", and , lagneía, "lust") is a sexual tendency which is defined by deriving sexual pleasure and stimulation from physical pain, often involving an erogenous zone. Studies conducted indicate differences in how the brains of those with algolagnia interpret nerve input.

==History of research== In 1892, Albert von Schrenck-Notzing introduced the term algolagnia to describe "sexual" masochism, to differentiate it from Charles Féré's earlier term called "algophilia"; Schrenck-Notzing's interpretation was that algolagnia involved lust, not love as Fere interpreted the phenomenon. (It should be cautioned, though, that the definitions regarding sadism and masochism as medical terms have changed over the years (as also noted in the main article for that topic) and are still evolving, and there are also non-medical definitions of sadomasochism.) However, Krafft-Ebing's theories in Psychopathia Sexualis – where the terms sadism and masochism were used – were adopted by Sigmund Freud and became an integral part of psychoanalysis, thereby ensuring their predominance over the concept of "algolagnia".