Delusions

Delusions are fixed false beliefs held with conviction that resist correction by reason or evidence.

As a drug effect they are acute and high-dose-dependent, resolving as the substance wears off, which sets them apart from a primary psychotic disorder. They range from fleeting misinterpretations of meaning to elaborate, stable false beliefs that direct dangerous behavior.

Delusions are among the rarest drug-induced adverse effects and among the most consequential when they occur. They are most commonly induced at high doses under psychedelics such as LSD, psilocybin mushrooms, and DMT, and under stimulants such as amphetamine, methamphetamine, and 6-APB. They also appear under dissociatives like ketamine, dextromethorphan, and 3-MeO-PCP, and under synthetic cannabinoids such as THJ-018, JWH-018, and 5F-AKB48.

Delusions are felt as certainty that cannot be argued away: a conviction, with the quality of plain fact, that events are orchestrated, others are conspiring, or one possesses special knowledge or powers. Reasoning finds no purchase.

They commonly come with heightened vigilance and a scanning attention that reads ordinary details as saturated with hidden significance. The certainty compounds itself — each new observation confirms the belief rather than questioning it. At high doses under dissociatives, the false frame can become total and sealed off from any external correction.

Delusions arise through different pathways depending on the drug class:

• Psychedelics — act on 5-HT2A receptors, loosening the brain's ordinary constraints on belief formation; false premises take hold with the felt quality of certainty.
• Stimulants — drive excess dopamine signaling in salience circuits; ordinary stimuli acquire heavy felt significance, and paranoid or grandiose frameworks emerge to explain it.
• Dissociatives — block NMDA receptors, fragmenting the sense of shared reality enough that isolated false world-models can crystallize.
• Cannabinoids — act on CB1 receptors; synthetic cannabinoids carry substantially higher risk than conventional preparations.

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

Who experiences delusions, and how severely, varies widely. They are rare at moderate doses and become more likely only at high doses across all classes. Set and setting matter substantially — especially under psychedelics and dissociatives — and a personal or family history of psychosis makes onset far more likely.

Unlike milder adverse effects, expectation offers little protection; delusions tend to arrive without warning, and the person experiencing them is rarely aware they have begun. Sleep deprivation combined with stimulant use markedly increases risk.