Attention problems are common in schizophrenia. So are difficulty starting tasks, losing track mid-conversation, forgetting appointments, and feeling like the brain is "fuzzy." These are also classic ADHD complaints. So is it possible to have both? Can ADHD be misdiagnosed as schizophrenia, or the other way around? And what about stimulants — the standard ADHD treatment — in someone with a history of psychosis?
ADHD and schizophrenia share attention and executive symptoms, but ADHD is a neurodevelopmental condition that begins in childhood, while schizophrenia is a psychotic disorder that typically emerges in late adolescence — and they can co-occur.
What ADHD actually is
According to the DSM-5-TR, ADHD requires symptoms of inattention and/or hyperactivity-impulsivity that began before age 12, are present in two or more settings (school, home, work), and cause functional impairment. It does not include hallucinations or delusions. The NIMH ADHD overview is a useful starting point.
The overlap
People with schizophrenia frequently report attention difficulties that look ADHD-like — trouble focusing on a book, losing the thread of a conversation, forgetting why they walked into a room. The MATRICS Consensus Cognitive Battery, a standard tool for measuring cognition in schizophrenia, includes attention as a core domain. The MATRICS programme (Nuechterlein et al., 2008) documented that attention impairment is one of the most consistent cognitive findings in the disorder.
Several large studies, including a Danish national cohort published in The Lancet Psychiatry, have found that childhood ADHD is associated with a roughly 4–5× higher risk of later being diagnosed with a schizophrenia spectrum disorder, although the absolute risk remains low. This shared liability may reflect overlapping genetic and neurodevelopmental factors.
How clinicians tell them apart
Age of onset
ADHD symptoms must be present from childhood. If attention problems first appear at age 18 or 22, ADHD is unlikely to be the right label, and a psychotic, mood, or substance-use cause should be considered first.
Presence of psychosis
ADHD does not include hallucinations or delusions. If those are present, the diagnosis is in the psychotic spectrum, even if ADHD-like attention symptoms also exist.
Pattern of impairment
ADHD impairment is typically distractibility and impulsivity — the person is energetic but scattered. Schizophrenia cognitive impairment is more often a slowing — the person is processing more slowly, with reduced working memory.
Negative symptoms
Flat affect, anhedonia, alogia, and social withdrawal point toward schizophrenia, not ADHD.
Can both be present at the same time?
Yes. The DSM-5-TR allows simultaneous diagnosis. A person with childhood-onset ADHD can also develop schizophrenia later. In these cases, careful documentation of the two timelines matters: clinicians want to know which symptoms started when, and which respond to which treatment.
The stimulant question
Stimulants — methylphenidate, amphetamine — are the first-line treatment for ADHD. They work by increasing dopamine and norepinephrine in the prefrontal cortex. Because dopamine excess is implicated in psychosis, stimulants can sometimes trigger or worsen psychotic symptoms. The FDA labelling for amphetamine products includes warnings about the risk of new-onset psychosis. See our deep dive at stimulants and antipsychotics.
Stimulant medication is associated with new or worsening voices, paranoia, or grandiose thinking. Do not stop the medication abruptly — contact the prescriber the same day.
Treating ADHD-like symptoms in schizophrenia
For someone with stable schizophrenia and persistent attention problems, options that prescribers consider include:
- Cognitive remediation therapy — structured exercises that improve attention, working memory, and processing speed. See our overview.
- Non-stimulant ADHD medications — atomoxetine, guanfacine, clonidine — generally lower psychosis risk than stimulants.
- Optimising the antipsychotic — some antipsychotics are more "cognitively friendly" than others.
- Lifestyle factors — sleep, exercise, and reducing caffeine and nicotine swings, all of which affect attention.
Stimulants are sometimes used cautiously in people with stable schizophrenia, but only after careful weighing of risks and with close monitoring.
The bottom line
ADHD and schizophrenia overlap in attention and executive function but differ fundamentally in what they are. If you have schizophrenia and feel that attention is your biggest day-to-day struggle, it's worth a focused conversation with your prescriber about whether some of those symptoms are part of schizophrenia, part of medication side effects, or part of a separate ADHD diagnosis — and what might help.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.