Taste suppression

Taste suppression is a reduction or loss of the ability to perceive flavor, arising as a direct drug effect rather than as a symptom of illness or structural damage to taste receptors.

As a drug effect it is acute and dose-proportional; it eases fully as the substance wears off, which distinguishes it from clinical conditions such as ageusia. It ranges from a mild dulling in which familiar flavors seem flat and indistinct to a near-complete absence of gustatory sensation.

Taste suppression is an uncommon effect. It is most commonly induced at moderate to high doses under dissociatives such as memantine.

Taste suppression is felt as a veil drawn over gustatory experience: flavors that would ordinarily be sharp or complex arrive faint, stripped of their defining character. Food and drink may seem texturally present but experientially hollow, as though taste has been turned down like a volume dial.

The effect is most conspicuous with foods that carry strong, familiar profiles — the gap between what is expected and what arrives makes the suppression hard to miss. At higher doses the diminishment can extend to the point where eating feels functionally purposeless.

Taste suppression arises through different pathways depending on the drug class:

• Dissociatives — act as NMDA receptor antagonists; NMDA receptors are expressed in peripheral taste receptor cells and in central gustatory processing pathways, and their blockade is thought to reduce the fidelity of taste signal transmission from tongue to cortex.

How much each pathway contributes in a given case is not fully understood.

Who experiences it, and how strongly, varies widely. Higher doses raise both likelihood and depth of suppression; at low doses flavors may be only mildly dulled, while at high doses the effect can approach near-total absence.

Set and setting play a lesser role here than in effects with emotional valence, though prior familiarity with a substance's effects may make the suppression easier to anticipate rather than notice with alarm. Individuals with heightened baseline gustatory sensitivity tend to register it sooner and more acutely.