Depression

Depression is a sustained low mood, emotional blunting, and loss of motivation arising during or after substance use.

As a drug effect it is acute and dose-proportional, easing as the substance clears, which distinguishes it from a standing depressive disorder. It ranges from a mild flatness of affect to profound emotional collapse, and at its most severe carries a real risk of self-harm.

It is reported across many drug classes, though less commonly than effects such as anxiety or sedation. It is most commonly experienced as an aftereffect at moderate to high doses of stimulants such as amphetamine, MDMA, and cocaine, and as a rebound from depressants like alcohol, baclofen, and F-phenibut as they wear off. It also appears following use of deliriants such as diphenhydramine and datura, and under psychedelics such as psilocybin mushrooms and MDA.

Depression is felt as a hollowing-out of affect: the capacity to feel pleasure dulls, motivation drains, and tasks that felt manageable become unreachable.

It commonly comes with physical heaviness — a leaden fatigue in the limbs, slowed speech, and a flat or constricted expression — alongside a background sense of meaninglessness that is difficult to reason away. Rumination deepens it; attending to the low mood tends to make it feel more permanent. At higher doses, particularly following stimulants, the state can collapse into hopelessness or thoughts of self-harm.

Depression arises through different pathways depending on the drug class:

• Stimulants — deplete dopamine and serotonin during heavy use; the subsequent deficit surfaces as low mood, anhedonia, and fatigue in the hours or days that follow.
• Depressants — chronic use downregulates inhibitory receptor systems; as they wear off, the compensatory rebound produces dysphoria.
• Deliriants — produce a post-use depressive state through anticholinergic mechanisms that are less well characterized.
• Psychedelics — can trigger depression in predisposed individuals, particularly in the days after a difficult experience.

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

Who experiences it, and how strongly, varies widely. Higher doses and longer sessions raise both likelihood and severity — a single moderate dose may produce little aftereffect while heavy repeated use reliably does.

Set and setting shape it, especially under psychedelics: an emotionally difficult experience raises the risk of a depressive aftermath. People with a personal or family history of depression or mood disorders are substantially more vulnerable. Adequate sleep, nutrition, and recovery time between sessions reduce it.