Limerence
Limerence refers to an involuntary cognitive and emotional state of intense romantic desire for another person. The term was coined by psychologist Dorothy Tennov to describe the ultimate, near-obsessional form of romantic love.

# Overview
The concept is an attempt at a scientific study into the nature of romantic love. Limerence can often be what is meant when one expresses having intense feelings of attachment and preoccupations with the love object.
According to Tennov, there are at least two types of love: limerence, what she calls "loving attachment", and "loving affection," the bond that exists between an individual and his or her parents and children.
Limerence is characterized by intrusive thinking and pronounced sensitivity to external events that reflect the disposition of the limerent object towards the individual. It can be experienced as intense joy or as extreme despair, depending on whether the feelings are reciprocated.
Unlike English, many other languages have traditional terms to denote limerence, like the German Verliebtheit, Scandinavian forelskelse, Brazilian Portuguese paixonite, or Russian  (vlyublyonnost); these expressions may roughly be translated to fallen-in-love-ness.

# Origins
The concept of limerence first originated in Tennov's research in the mid-1960s.  She interviewed over 500 people on the topic of love. Tennov coined the term "limerence" in 1977, publishing it in her 1979 book "Love and Limerence: The Experience of Being in Love".
Tennov differentiates between limerence and other emotions by asserting that love involves concern for the other person's welfare and feeling. While limerence does not require it, those concerns may certainly be incorporated.
Affection and fondness exist only as a disposition towards another person, irrespective of whether those feelings are reciprocated, whereas limerence demands return. Physical contact with the object is neither essential nor sufficient to an individual experiencing limerence, unlike one experiencing sexual attraction.
New Relationship Energy (NRE) thrives on open communication and known mutuality of feelings and is mostly seen as a positive bonding experience, while limerence can dissipate once reciprocity is established, and is characterized by uncertainty and anxiety.
New Relationship Energy also carries implications of active contrast with relationships in different stages, while limerence does not. Limerence can be longer-lived than transient forms of romantic feelings such as infatuation and puppy love, enduring for months, years and even a lifetime in the absence of knowledge about reciprocity.

# Components
Limerence involves  intrusive thinking about the limerent object. Other characteristics include acute longing for reciprocation, fear of rejection, and unsettling shyness in the limerent object's presence. In cases of unrequited limerence, transient relief may be found by vividly imagining reciprocation from the limerent object.
Feelings of limerence can be intensified through adversity, obstacles, or distance. A limerent person may have acute sensitivity to any act, thought, or condition that can be interpreted favorably. This may include a tendency to devise, fabricate, or invent "reasonable" explanations for why neutral actions are a sign of hidden passion in the limerent object.
A person experiencing limerence has a general intensity of feeling that leaves other concerns in the background. In their thoughts, a limerent person tends to emphasize what is admirable in the limerent object and to avoid any negative or problematic attributes.

## Intrusive thinking
During the height of limerence, thoughts of the limerent object (or person) are both persistent, involuntary and intrusive. Limerence is first and foremost a condition of cognitive obsession. All events, associations, stimuli, and experiences return thoughts to the limerent object with unnerving consistency.
The constant thoughts about the limerent object define all other experiences. If a certain thought has no previous connection with the limerent object, immediately one is made. Limerent fantasy is unsatisfactory unless rooted in reality, because the fantasizer may want the fantasy to seem realistic and somewhat possible.
Fantasies that are concerned with farfetched ideas are usually dropped by the fantasizer. Sometimes it is retrospective; actual events are replayed from memory with great vividness. This form predominates when what is viewed as evidence of possible reciprocation can be re-experienced (a kind of selective or revisionist history).
Otherwise, the long fantasy is anticipatory; it begins in the everyday world and climaxes at the attainment of the limerent goal. A limerent fantasy can also involve an unusual, often tragic, event.
The long fantasies form bridges between the limerent's ordinary life and that intensely desired ecstatic moment. The duration and complexity of a fantasy depend on the availability of time and freedom from distractions. The bliss of the imagined moment of consummation is greater when events imagined to precede it are possible.
In fact they often represent grave departures from the probable. Not always is it entirely pleasant, and when rejection seems likely the thoughts focus on despair, sometimes to the point of suicide. The pleasantness or unpleasantness of the state seems almost unrelated to the intensity of the reaction.
Although the direction of feeling, i.e. happy versus unhappy, shifts rapidly, the intensity of intrusive and involuntary thinking alters less rapidly, and alters only in response to an accumulation of experiences with the particular limerent object.
For example, fantasies may include "rescuing" the limerent object from a situation of peril and being rewarded in some way implying reciprocation.  Another example of limerent fantasy would include a limerent object proclaiming love in a climactic fashion, such as in dying moments.
Fantasies also are occasionally dreamed by the one experiencing limerence. Dreams give out strong emotion and happiness when experienced, but often end with despair when the subject awakens. Dreams can reawaken strong feelings toward the limerent object after the feelings have declined.

## Fear of rejection
Along with the emphasis on positive qualities perceived in the limerent object, and preoccupation with the hope for return of feelings, there is a fear that limerence will be met by the very opposite of reciprocation: rejection. Considerable self-doubt and uncertainty is experienced and it causes pain, but also enhances desire to a certain extent.
However in most cases, this is what helps to eventually destroy the limerence if a suitably long period of time has passed without reciprocation.  Typically, limerence lasts about 3 years, but, as previously mentioned, can last decades or even a lifetime.
Limerent fear of rejection is usually confined to shyness in the presence of the limerent object, but it can also spread to situations involving other potential limerent objects, though generally it does not affect other spheres of life.
Although it appears that limerence blossoms under some forms of adversity, extreme caution and shyness may prevent a relationship from occurring, even when both parties are interested.  This results from a fear of exposing one's undesirable characteristics to the limerent object.

## Hope
Limerence develops and is sustained when there is a certain balance of hope and uncertainty. The base for limerent hope is not in objective reality but reality as it is perceived. The inclination is to sift through nuances of speech and subtleties of behavior for evidence of limerent hope. "Little things" are noticed and endlessly analyzed for meaning.
The belief that the limerent object does not and will not reciprocate can only come about with great difficulty. Limerence can be carried quite far before acknowledgment of rejection is genuine, especially if it has not been addressed openly by the object of limerence.
Excessive concern over trivia may not be entirely unfounded. Body language can indicate a return of feeling. What the limerent object said and did is recalled with vividness, mostly due to the release of certain 'romance chemicals'. Alternative meanings of those behaviors recalled are searched out.
Each word and gesture is permanently available for review, especially those which can be interpreted as evidence in favor of "return of feeling." When objects, people, places or situations are encountered with the limerent object, they are vividly remembered, especially if the limerent object 'interacted' with them in some way.

## Physical effects
The physiological correlations of limerence are heart palpitations, trembling, pallor, flushing, pupil dilation and general weakness. Awkwardness, stuttering, shyness, and confusion predominate at the behavioral level.
There is apprehension, nervousness, and anxiety due to terrible worry that any action may bring about disaster. Many of the commonly associated physiological reactions are the result of the limerent fear. Some people however may find that these effects come most strongly either immediately at or some time after contact with the object of limerence, and this is accompanied with an acute feeling of ecstasy or despair, depending on the turn of events beforehand.
The super-sensitivity that is heightened by fear of rejection can get in the way of interpreting the limerent object's body language and lead to inaction and wasted opportunities. Body signals may be emitted that confuse and interfere with attaining the limerent object.
A condition of sustained alertness, a heightening of awareness and an enormous fund of energy to deploy in pursuit of the limerent aim is developed. The sensation of limerence is felt in the midpoint of the chest, or in some cases in the abdominal region. This can be interpreted as ecstasy at times of mutuality, but its presence is most noticeable during despair at times of rejection.

## Game-playing
No matter how intensely reciprocation is desired it cannot simply be requested. To ask is to risk premature self-disclosure. The interplay is delicate, with the reactions of each person inextricably bound to the behavior of the other - or at least so in the mind of the Limerant.
Progression toward ecstatic mutuality may not involve externally created difficulties but feinting and parrying, minor deceptions, and falsehoods. The uncertainty required by the limerent reaction may often be merely a matter of perception. Despite ideals and philosophy, a process begins that bears unquestionable similarity to a game. The prize is not trifling: reciprocation produces ecstasy.
Whether it will be won, whether it will be shared, and what the final outcome may be depends on the effectiveness of actions and those of the limerent object; indeed on skill. Deviations from straightforward honesty become essential limerent strategies.
Fears lead to proceeding with a caution that will hopefully protect from disaster. Reason to hope combined with reason to doubt keeps passion at fever pitch and too-ready limerent availability cools. Open declaration of true feelings may stop the process.
Limerent uncertainty as well as projection can be viewed as the consequence of the limerent inclination to hide feelings. Because one of the invariant characteristics of limerence is extreme emotional dependency on the limerent objects behavior, the actual course of limerence must depend on the actions and reactions of both people.
Uncertainty increases limerence; increased limerence dictates altered action, which serves to increase or decrease limerence in the other according to the interpretation given. The interplay is delicate if the relationship hovers near mutuality; a subtle imbalance, constantly shifting, appears to maintain it.
In most cases each person knows who is more limerent, but this is not always so. In most cases the limerents may believe a certain viewpoint, but the constant uncertainty means they are doubting or questioning themselves for most of the time regarding the other person. This can vary widely between different people.

## Sexuality
Awareness of physical attraction plays a key role in the development of limerence, but is not enough to satisfy the limerent desire, and is almost never the main focus -- instead, the limerent focuses on what could be defined as the "beneficial attributes".
A person, to become the limerent object, must be a potential sex partner. Limerence can be intensified after a sexual relationship has begun, and with more intense limerence there is greater desire for sexual contact. However, while sexual surrender once indicated the end of uncertainty in the limerent object, in modern times this is not necessarily the case.
Sexual fantasies are distinct from limerent ones. Limerent fantasy is rooted in reality and is intrusive rather than voluntary. Sexual fantasies are under more or less voluntary control and may also involve strangers, imaginary individuals, and situations that could not take place.
People can become aroused by the thought of sexual partners, acts, and situations that are not truly desired, whereas every detail of the limerent fantasy is passionately desired actually to take place. Limerence sometimes increases sexual interest in other partners when the limerent object is unreceptive or unavailable, such as when married people find sex with their spouses more pleasurable when they become limerent over someone else.
Limerent anxieties and shyness may interfere with sexual functioning. The continual concern to appear at the very best is not always compatible with the immodest behaviors and poses that arise in sexual situations.

# Limerent reaction
The limerent reaction is a composite reaction; that is, it actually describes a unique series of reactions.  These reactions occur only where misperceptions meet adversity in the context of a romance.  Perhaps because of this unique specificity, limerent reactions can be uniquely quantified and predicted according to the schema described below.
Involvement increases if obstacles are externally imposed or if the limerent objects feelings are doubted. Only if the limerent object were to be revealed as highly undesirable might limerence subside. The presence of some degree of doubt causes the intensity of the feelings to rise further.  The stage is reached at which the reaction is virtually impossible to dislodge.
This adversity may be superficial or deep, internal or external, so that an individual may generate deep adversity where none exists.  Also "romance," as it were, need not be present in any genuine way for a limerent reaction to proceed.
The course of limerence results in a more intrusive thinking pattern. This thinking pattern is an expectant and often joyous period with the initial focusing on the limerent objects admirable qualities; crystallization. Then, under appropriate conditions of hope and uncertainty, the limerence intensifies further.
With evidence of reciprocation from the limerent object, a state of extreme pleasure, even euphoria, is enjoyed. Thoughts are mainly occupied with considering and reconsidering what is attractive in the limerent object, replaying whatever events may have thus far transpired with the limerent object, and appreciating personal qualities which are perceived as possibly having sparked interest in the limerent object.
At peak crystallization, almost all waking thoughts revolve around the limerent object. After this peak, the feelings eventually decline.
Fantasies are preferred to virtually any other activity with the exception of activities that are believed to help obtain the limerent object, and activities that involve actually being in the presence of the limerent object. The motivation to attain a "relationship" continues to intensify so long as a proper mix of hope and uncertainty exist.
Tennov estimates, based on both questionnaire and interview data, that the average limerent reaction duration, from the moment of initiation until a feeling of neutrality is reached, is approximately three years. The extremes may be as brief as a few weeks or several years. When limerence is brief, maximum intensity may not have been attained.
Limerence generally lasts between 18 months and three years, but further studies on unrequited limerence have suggested longer durations.

# Bond varieties
Once the limerent reaction has initiated, one of three varieties of bonds may form, defined over a set duration of time, in relation to the experience or non-experience of limerence.  The constitution of these bonds may vary over the course of the relationship, in ways that may either increase or decrease the intensity of the limerence.
The basis and interesting characteristic of this delineation made by Tennov, is that based on her research and interviews with people, all human bonded relationships can be divided into three varieties being defined by the amount of limerence or non-limerence each partner contributes to the relationship.
With an affectional bond, neither partner is limerent. With a Limerent-Nonlimerent bond, one partner is limerent. In a Limerent-Limerent bond, both partners are limerent.
Affectional bonding characterize those affectionate sexual relationships where neither partner is limerent; couples tend to be in love, but do not report continuous and unwanted intrusive thinking, feeling intense need for exclusivity, or define their goals in terms of reciprocity.  These types of bonded couples tend to emphasize compatibility of interests, mutual preferences in leisure activities, ability to work together, and in some cases a degree of relative contentment.
The bulk of relationships, however, according to Tennov, are those between a limerent person and a nonlimerent other, i.e. limerent-nonlimerent bonding.  These bonds are characterized by unequal reciprocation.
Lastly, those relationship bonds in which there exists mutual reciprocation are defined as limerent-limerent bondings.  Tennov argues since limerence itself is an "unstable state" that mutually limerent bonds would be expected to be short-lived; mixed relationships probably last longer than limerent-limerent relationships; and affectional bondings tend to be characterized as "old marrieds" whose interactions are typically both stable and mutually gratifying.

# Impact
Tennov's research has been continued by Albert Wakin, who knew Tennov at the University of Bridgeport but didn't assist in her research, and Duyen Vo, a graduate student of Southern Connecticut State University.  They are refining the term to refer to the negative pathological aspects of Limerence.  The term "Limerence" has been invoked in many popular media, including self-help books, popular magazines, and websites.
Still, according to a paper by Wakin and Vo, "In spite of the publics exposure to limerence, the professional community, particularly clinical, is largely unaware of the concept."  In 2008, they presented their updated research to the American Association of Behavioral and Social Sciences.  Wakin and Vo reported that more research must be gathered before the condition is suited for the Diagnostic and Statistical Manual of Mental Disorders (DSM).