Dopamine Signalling

Prefrontal Cortex

Planning, judgement and the brake on impulse. Relevant here because the reported behaviour change on these compounds is often better described as a weaker brake than as a stronger drive, and those two have different consequences.

Dopamine D2 Receptor

The dopamine receptor that holds prolactin down and carries reward and motivation signalling. Losing D2 tone raises prolactin and flattens drive and sexual response.

Dependence and Withdrawal

Difficulty stopping despite harm, with low mood, lost drive and fatigue on withdrawal. Recognised as a genuine dependence syndrome in around a third of long-term users, not a character failure.

Emotional Blunting

A narrowed range in both directions: less low, but also less warmth, less connection and less feeling for other people. Distinct from loss of pleasure, which is about reward specifically. Worth separating because the person experiencing it often rates it as an improvement while the people around them do not.

Loss of Pleasure

Things that used to be enjoyable stop landing. Distinct from low mood: a person can have normal mood and still get nothing out of food, sex, music or company. Reported most on the progestogenic and prolactin-raising compounds, and it is the effect people most often fail to name because it does not feel like sadness.

Drive and Motivation

Willingness to start things and to keep going. Reported separately from mood and separately from libido, and it moves separately: compounds exist that lift mood and flatten drive, and the reverse.

Euphoria

A lifted, expansive, everything-is-working feeling, arriving within days on some compounds. Recorded because it is real, because it is a large part of why people continue, and because it is the strongest single predictor of the dependence pattern further down. Not marked as good or bad: it is the reward that makes the rest of the list acceptable to the person having it.