Interpersonal love refers to love between human beings.
It is a much more potent sentiment than a simple liking for a person.
Unrequited love refers to those feelings of love that are not reciprocated.
Interpersonal love is most closely associated with interpersonal relationships.
If sexual passion is also involved, then this feeling is called paraphilia.
Non-Western traditions have also distinguished variants or symbioses of these states.Lust is the feeling of sexual desire; romantic attraction determines what partners mates find attractive and pursue, conserving time and energy by choosing; and attachment involves sharing a home, parental duties, mutual defense, and in humans involves feelings of safety and security.Lust is the initial passionate sexual desire that promotes mating, and involves the increased release of chemicals such as testosterone and estrogen.Recent studies in neuroscience have indicated that as people fall in love, the brain consistently releases a certain set of chemicals, including the neurotransmitter hormones, dopamine, norepinephrine, and serotonin, the same compounds released by amphetamine, stimulating the brain's pleasure center and leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement.
Research has indicated that this stage generally lasts from one and a half to three years.
Many other languages use multiple words to express some of the different concepts that in English are denoted as "love"; one example is the plurality of Greek words for "love" which includes agape and eros.