Substance-induced psychosis belongs high on the differential and is often mislabeled as schizophrenia, but do not write everything off to substances: a primary psychotic disorder can co-occur, and psychosis from a drug that rarely causes it suggests vulnerability. How likely the substance is to cause psychosis, and how it was used, matter: brief psychosis after days awake on Adderall is not heavy methamphetamine use. Acute episodes are treatable and transient, but delusional systems from methamphetamine can persist.
What it is
Substance-induced (and mood-induced) delusions are still in the psychotic realm. The difference is that they are not chronic.
“I would say that category two and three, the substance induced and the mood induced, I would still consider those within the psychotic realm. It's simply that they're from a non-permanent or non-chronic is the better word”
18:35What Makes a Belief a Delusion? Delusions, Thought Disorder, the TALD ScaleJan 2026 In our clinical, non-scientific experience, long-term substance-induced psychosis has more positive than negative symptoms. In the end, the question is less what caused it than what will help treat it.
“In my clinical, non-scientific experience, they seem to have more positive symptoms than negative. But in the end, what we're trying to determine most of the time as a clinician is not what caused this, but what's going to help treat this”
24:14What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026
Diagnosis and differential
It is one of the biggest mimics: patients who come in with substance-induced psychosis or chronic use get tacked on with schizophrenia.
“the biggest ones that I saw is definitely substance use, chronic substance use, or patients who come in with a substance-induced psychosis and they get tacked on with schizophrenia. Other big ones are PTSD is another big one. Patients with borderline personality disorder”
20:17What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026 Do not write off the possibility of a primary psychotic disorder co-occurring with a substance use disorder.
“It is possible for someone with a primary psychotic disorder to have a substance use disorder too, and we can't write off the possibility of a primary psychotic disorder co-occurring with a substance use disorder”
21:14What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026 Consider how likely the substance is to cause psychosis. Psychosis from a drug that does not cause it in most people at that dose, like cannabis at a lower dose, suggests more vulnerability.
“if you have a substance-induced psychosis from a drug that does not cause psychosis in most people most people like cannabis yes at a very very high dose Most people can get a little psychotic on cannabis, but most people do not on a lower dose, but some people do”
54:31What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026 Heavy methamphetamine use can cause so much disorganization and delusion that, even after stopping, the person looks exactly like someone with schizophrenia. A paranoid delusional belief system that began on methamphetamine can persist after the perceptions that fed it stop.
“someone can can cause so much disorganization and delusions and odd belief systems in their brain that now there's no different there's no if this person were to stop using meth they'll look the exact same as someone who has schizophrenia”
23:49What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026 Also said in 1 more episode
“the ones that get paranoid on methamphetamine can develop a delusional belief system. And even if they stop getting the perceptions that support that delusional belief system after they stop using the methamphetamine, that delusional system can persist as a belief”
36:48Psychosis: History, Delusions, Diagnosis, Theories, and Modern CareNov 2024 Some young adults with true childhood ADHD develop stimulant-induced psychosis around 18 or in their twenties. You know because the psychotic symptoms stop when the stimulant is stopped.
“once they're starting to turn 18 or in their 20s, they start developing stimulant-induced psychosis. Okay. And how do I know it's that? Because I pull them off the stimulants and the psychotic symptoms stop”
38:14ADHD Is Not the Only Diagnosis: Differential and Diagnostic HierarchyNov 2025
Treatment approach
Violence and dangerousness during intoxication and for a week or two after is treatable: monitor, keep them in a safe place and give temporary antipsychotics. That makes it a legitimate use of involuntary treatment.
“If somebody is violent and dangerous while they're intoxicated and for about maybe, let's say, a week or two after, let's pretend they have a substance induced psychotic disorder. Then that's treatable, right? You monitor, you keep them in a safe location, you give temporary antipsychotics”
21:45Involuntary Treatment & Agency, Thoughts and Feelings | Episode 19Mar 2025
From these episodes
- What Makes a Belief a Delusion? Delusions, Thought Disorder, the TALD ScaleJan 2026 · 1 point
- What is Psychosis? Look at the DSM, Common Mimics, and a Framework for the DifferentialJan 2026 · 5 points
- ADHD Is Not the Only Diagnosis: Differential and Diagnostic HierarchyNov 2025 · 1 point
- Involuntary Treatment & Agency, Thoughts and Feelings | Episode 19Mar 2025 · 1 point
- Psychosis: History, Delusions, Diagnosis, Theories, and Modern CareNov 2024 · 1 point
Every point above is something said on the Psychofarm podcast, with the words as spoken and a link to the moment in the episode. It is education, not medical advice, and an episode reflects what we thought when we recorded it.