Several categories of drugs can cause people to talk to themselves, typically by triggering hallucinations, psychosis, or a delirious state where the boundary between internal thoughts and outward speech dissolves. Stimulants like methamphetamine and cocaine are the most commonly reported, but the list also includes cannabis products, dissociatives, anticholinergic substances, and certain prescription medications. The behavior usually stems from auditory hallucinations (hearing voices that aren’t there) or a loss of awareness that inner thoughts are being spoken aloud.
Stimulants: Meth and Cocaine
Methamphetamine is one of the drugs most strongly linked to talking to oneself. Meth-induced psychosis produces persecutory delusions in roughly 84% of documented cases and auditory hallucinations in about 69%. A person in this state may hear voices making threats or commands and respond to them out loud, sometimes carrying on full conversations with no one. These episodes can look strikingly similar to schizophrenia, and they tend to worsen with higher doses, longer binges, and sleep deprivation.
Cocaine produces a similar picture. In one study of 55 people with cocaine addiction, more than half reported psychotic symptoms. Among those, 96% experienced hallucinations (most commonly auditory) and 90% had paranoid delusions. Talking to oneself in this context is often a response to voices or an expression of paranoid thought patterns playing out verbally.
Both drugs flood the brain with dopamine, which at excessive levels disrupts the ability to distinguish real sensory input from internally generated signals. That excess dopamine is the core mechanism behind stimulant psychosis and the vocalization that comes with it.
Cannabis and Synthetic Cannabinoids
High-potency cannabis and especially synthetic cannabinoids (sometimes sold as “Spice” or “K2”) can trigger psychotic episodes that include self-talk. Synthetic cannabinoids are particularly unpredictable because they bind to brain receptors far more powerfully than natural THC. In clinical case reports, heavy or prolonged use of synthetic cannabinoids has produced a recognizable pattern: self-talk, inappropriate laughter, catatonia, and paranoid delusions. One documented case involved a patient who developed persistent self-talk and catatonia after 18 months of continuous synthetic cannabinoid use.
Regular cannabis at standard potency carries a lower risk, but it can still push vulnerable individuals into brief psychotic states, particularly at high doses or with products containing very high THC concentrations.
Anticholinergic and Deliriant Substances
This category is perhaps the most dramatic when it comes to talking to people who aren’t there. Anticholinergic drugs block a brain signaling system involved in perception, cognition, and attention. When that system is suppressed, the result is delirium: vivid visual hallucinations that look completely real to the person experiencing them, combined with confused, often pressured speech.
The classic examples include diphenhydramine (Benadryl) at very high doses and plants like jimsonweed. But prescription anticholinergics can do the same thing. In one case report, a patient given the anticholinergic medication procyclidine began mumbling, then progressed to talking to himself, then started feeding cats and dogs that weren’t actually present in his room. His speech became slurred and almost incomprehensible. Picking at invisible objects and interacting with hallucinated animals or people is a hallmark of anticholinergic delirium.
What makes deliriants different from psychedelics is that the person genuinely cannot tell the hallucinations aren’t real. Someone on LSD typically knows the visual distortions are drug-induced. Someone in anticholinergic delirium will hold full conversations with imaginary people and have no awareness they’re alone.
Dissociatives: PCP and Ketamine
Phencyclidine (PCP, or “angel dust”) and ketamine both block a type of brain receptor involved in thought organization and sensory processing. Both can produce hallucinations, delusions, illogical thinking, and disordered speech. PCP is the more potent of the two in terms of psychotic effects. People under its influence may talk to themselves, speak incoherently, or respond to hallucinated stimuli. Ketamine can produce similar symptoms, though typically at high doses or with repeated use. The speech disturbances with dissociatives often have a distinct “disconnected” quality, where the person seems to be narrating or responding to an internal experience that has no connection to their surroundings.
Prescription Medications
Several prescription drug classes list psychosis or hallucinations as potential side effects. Corticosteroids (used for inflammation and autoimmune conditions) can induce mood changes and anxiety that escalate into full psychosis with auditory hallucinations. Antiepileptic drugs, antimalarial medications, and some antiretroviral drugs have all been documented to cause persecutory delusions and auditory hallucinations in certain patients. In most of these cases, mood changes and anxiety appear first, followed by psychotic symptoms if the medication continues.
Sleep medications, particularly zolpidem (Ambien), can produce a different phenomenon. About 3.3% of users in one large study reported sleepwalking or amnesic sleep-related behaviors, which occasionally include talking to others or talking aloud with no memory of doing so afterward. This is less psychosis and more a parasomnia, a state where parts of the brain are asleep while others activate complex behaviors including speech.
Why Drugs Cause Outward Self-Talk
The common thread across most of these substances is disrupted dopamine signaling. Stimulants directly increase dopamine. Cannabis and synthetic cannabinoids raise dopamine indirectly. Dissociatives alter glutamate signaling in ways that also affect dopamine pathways. When dopamine activity in certain brain circuits becomes excessive, the brain begins generating sensory experiences (especially voices) that feel as real as actual sounds. Responding to those voices verbally is a natural reaction, no different from how you’d respond to a real person speaking to you.
Anticholinergic drugs take a slightly different route, suppressing the brain’s acetylcholine system instead. This disrupts the ability to filter real perceptions from imagined ones, leading to a delirious state where imaginary people and objects become indistinguishable from reality.
Drug-Induced Psychosis vs. Psychiatric Illness
If someone is talking to themselves and it’s not clear whether drugs are involved, there are patterns that help distinguish drug-induced psychosis from conditions like schizophrenia. Drug-induced psychosis is more likely to involve visual hallucinations, while primary psychotic disorders tend to feature predominantly auditory hallucinations. People with substance-induced psychosis are also more likely to have a family history of substance abuse, while those with primary psychosis tend to show higher overall severity of psychiatric symptoms across multiple domains.
The most reliable distinguishing factor is time. Drug-induced psychosis typically resolves within days to weeks after the substance clears the body. If someone stops using the drug and the self-talk, hallucinations, or delusions persist beyond a month, that raises the possibility of an underlying psychiatric condition that was either triggered or unmasked by the drug use.