How would I describe the experience of MDMA? First, my shoulders relax. Then, I feel a shift in my social perception, others no longer "worry" me in quite the same way. I feel as if I could say whatever I wanted to anyone, and their response wouldn't bother me at all. I find it easy to fall deeply into conversations with others, maintaining direct eye contact and enjoying the interaction, without worrying about any sort of rejection. If they do start to shy away, I could shrug and move on, no harm no foul. But if they're open, I could reveal my darkest secrets without feeling any fear. What is going on here?
I would like to interpret the effects of MDMA using a Freudian lens, specifically through his concept of instinct, as elaborated in "Instincts and their Vicissitudes" (1915). A brief summary: instincts are stimuli arising from within the organism itself, that exert a continuous pressure on the organism. We may describe them as "needs", and they press for satisfaction. The goal of nervous system is to "master" stimuli, including instincts, to reduce their pressure to the lowest possible level. "Pleasure" broadly corresponds with a decrease in the overall level of stimulus acting on the organism, and "unpleasure" with an increase. Freud describes the instinct as "on the frontier between the mental and the somatic... the psychical representative of the stimuli originating from within the organism and reaching the mind, as a measure of the demand made upon the mind for work in consequence of its connection with the body."
Freud further divides instincts into two groups: "ego" or "self-preservative" instincts, and "sexual" instincts. The sexual instincts, he asserts, aim at the attainment of "organ-pleasure", which may include but is not limited to genital stimulation. In this sense, the act of eating a favorite food could be considered to satisfy a sexual instinct. Freud seems less certain about the unifying factor behind the ego instincts, but Lacan would later attempt to resolve this, by arguing the ego provides an attempt to create an image of self as a coherent unity. And hence, the "self-preservative" or "ego" instincts would involve fending off those stimuli which threaten the ego's status as a "whole".
Finally, Freud describes the relationships between "love" and "hate" and the instincts. He argues that, originally, objects which are sources of pleasure are "incorporated into the ego" or loved, whereas the ego "hates, abhors, and pursues with intent to destroy all objects which are a source of unpleasurable feeling", out of its instinct toward self-preservation. Thus, Freud argues that "the true prototypes for the relation of hate are derived not from sexual life, but from the ego's struggle to preserve and maintain itself", whereas "love" derives originally from a connection to "organ-pleasure", i.e. the sexual needs. The result of this split is the Freud does not treat "love" and "hate" as antitheses, but rather as originating from separate psychic needs, and thus both can coexist in one's relation to the same object. This echoes Spinoza's idea of "vacillation" toward an object both loved and hated.
With all of this background, I can put forth my thesis: that the effect of the substance of MDMA is to produce a temporary state of complete satisfaction of the self-preservation instincts. The results of this could appear as follows:
One might find it easier to express the instincts relating to "organ-pleasure", as they are no longer felt as "blocked" by having an ambivalent relation to the object. This expresses itself as the characteristic "enjoyment of touch" many experience on MDMA.
One might find it difficult to feel "hate" on MDMA. This is because, as argued above, "hate" originates from the self-preservation instincts. However, one might certainly feel "indifference" while on MDMA, which is how the sexual instinct "feels" about that which is not pleasurable. This relates to the experience of "no longer fearing rejection": if one no longer feels a need to guard their ego from experiences which conflict from their unified image of themselves, a rejection can no longer act to destabilize that common desire of "I want to be liked". Instead, the "inner feeling" of being on MDMA is a perfect stability and unity of self that no other person can touch. Hence, love or indifference, but no hate. This also permits great potential for deepening existing relationships, as certain social barriers within the relationship, erected to avoid potential rejection, are now of no concern.
There is a "problem" some users have on MDMA involving sex: they claim they are unable to achieve orgasm or maintain their potency while under its influence. My guess in this case is that sex, for many, involves some sort of ambivalence about the object. As both Freud and Spinoza note, love and hate do not "counteract" within the same object, but instead are "additive", in that one feels more strongly, with more intensity overall, about the object they simultaneously love and hate than they would about an object simply loved or hated. Thus if someone requires a certain threshold of stimulus in order to maintain their sexual potency, perhaps they rely to some extent on the addition of "hate" for their partner to love. This seems to align with common metaphors of seeing a sexual object as "prey", and also of the purpose of flirting and the dance of courtship: like fussy toddlers, we both love our desired object for what it promises to give us, but we also hate it for evading our grasp. Hence the sense of ambivalence surrounding sex, and without the "boost in intensity" due to hate, I would expect many would be unable to sustain the level of tension needed for a satisfying sexual encounter.
But this doesn't preclude sex entirely, as many also have stories of perfectly satisfying (or perhaps even more satisfying) sexual encounters on MDMA. For Freud, "love" exists on multiple levels: the oral level, of incorporating or devouring; the anal level, of "mastery" or annihilation; and the genital level, of union. These first two stages are fundamentally "ambivalent", in the sense that the distinction between "love" and "hate" is not yet clear in terms of the instinct's relation to its object. Regarding these stages, Freud claims that "in both cases, therefore, the admixed hate [which increases the intensity of desire] has as its source the self-preservative instincts" (which he also notes may persist after the love-relationship is broken off, leading one to "hate" their former partners). This supports my argument above that a full satisfaction or loss of pressure within the self-preservative instincts would possibly decrease one's "sexual potency". But interestingly, at the genital stage, the "love" and "hate" are no longer fused within the object, meaning a loss of self-preservative instincts would have no impact on sexual function.
As for a causal argument, "why?", I cannot say, besides there must be some relationship between serotonin and the self-preservation instinct. All I can do is draw this tentative connection between Freud's investigation and MDMA experiences I've either had first-hand or had related to me. More research is surely needed to demonstrate the correctness or falsity of my primarily speculative claims above.