Risperidone

Limits on what this shows

• Null/negative findings: No clinical, in vivo, human mitochondrial-function marker study in risperidone-treated patients was located.
• At-risk subgroups: Not established; theoretical only.

Regulatory status

Not addressed in the FDA label.

Population evidence

Toxicol In Vitro 2024 (PMID 39237056, human peripheral blood monocytes, in vitro): risperidone decreased ATP production in isolated mitochondria at about 70 micromolar, a supratherapeutic concentration well above typical clinical plasma exposure. Naunyn Schmiedebergs Arch Pharmacol 2019 (PMID 31104106, in vitro): examined antipsychotic effects, including risperidone, on mitochondrial electron transport chain complexes. In contrast, J Mol Neurosci 2015 (PMID 25750029, rat, in vivo dosing): risperidone reduced, rather than caused, mitochondrial dysfunction and apoptosis in a stress-re-stress paradigm, a protective direction.

Mechanism

At high in vitro concentrations risperidone appears to disrupt mitochondrial bioenergetics directly; at therapeutic-range in vivo dosing in an animal stress model it instead attenuated stress-induced mitochondrial injury. The net effect at clinical human doses is not predictable from the toxicological in vitro data alone.

Counter-evidence held on record

The concentration used in the human cell ATP study is roughly two to three orders of magnitude above steady-state clinical exposure. The rat behavioral model shows the opposite, protective, direction at in vivo dosing. This entry shares its primary source with ATP production below; see Overlap map. Do not interpret this entry as support for mitochondrial-support supplementation such as coenzyme Q10 in patients on risperidone; no clinical trial evidence supports this.

Limits on what this shows

• Null/negative findings: None identified among the human studies retrieved, all of which trend protective or antioxidant; the reverse (pro-oxidant) direction appears only in animal models below.
• At-risk subgroups: None established in humans; direction of effect appears tissue- and dose-dependent in animal models.

Regulatory status

Not addressed in the FDA label.

Population evidence

Biomedicines 2024 (PMID 39061992, human, drug-specific): in patients with psychotic disorder on risperidone or paliperidone, higher prolactin was associated with lower oxidative stress markers, titled "protective effect of hyperprolactinemia on oxidative stress." J Psychiatr Res 2015 (PMID 26228421, human, drug-naive first-episode psychosis before and after risperidone): examined oxidative stress biomarkers and described antioxidant effects of risperidone treatment. Biomed Pharmacother 2018 (PMID 29710513, human, mixed cohort on perphenazine, clozapine, and risperidone): evaluated oxidative stress markers and clinical correlations; risperidone-specific stratification could not be confirmed from the abstract retrieved, so this source is treated as supportive context rather than independent drug-specific confirmation.

Mechanism

Proposed mechanisms involve risperidone's receptor pharmacology and downstream effects on inflammatory and redox signaling; a specific named antioxidant biochemical mechanism for risperidone itself was not detailed in the retrieved abstracts.

Counter-evidence held on record

Andrologia 2021 (PMID 33108826, male rats): risperidone induced oxidative stress (altered glutathione, catalase, superoxide dismutase, malondialdehyde) targeting Leydig cells and the hypothalamic-pituitary-gonadal axis, a pro-oxidant, tissue-specific finding in a reproductive-toxicology model, not replicated in the human data reviewed. Front Neurosci 2018 (PMID 29937710, mice): risperidone pretreatment reduced LPS-induced oxidative stress in cortex and hippocampus, another protective-direction animal finding. This entry shares its hyperprolactinemia axis with the headline finding and the bone-density fails-verification entry; see Overlap map. This is a reverse-direction, context finding, not evidence that risperidone should be chosen or avoided for oxidative-stress reasons, and it does not support antioxidant supplementation.

Limits on what this shows

• Null/negative findings: None identified among the three drug-specific pediatric studies retrieved; all point the same direction. No parallel iron-status study in adult risperidone users was located, so this finding should not be extrapolated beyond long-term pediatric and adolescent use.
• At-risk subgroups: Children and adolescents on risperidone for roughly a year or more, especially with substantial treatment-associated weight gain.

Regulatory status

Not listed in the FDA label as an adverse reaction or a required monitoring parameter; this is a post-marketing research finding from independent pediatric psychiatry cohorts, not a labeled effect.

Population evidence

Calarge et al., J Child Adolesc Psychopharmacol 2013 (PMID 23480322): pediatric and adolescent patients on long-term risperidone (mean treatment duration about 2.4 years) showed 45 percent with iron depletion and 14 percent with frank iron deficiency, inversely associated with treatment-related weight gain. Calarge et al., J Child Adolesc Psychopharmacol 2016 (PMID 26894929): risperidone-treated youth had mean serum ferritin 37.3 microgram/L, with 21 percent below 20 microgram/L "despite appropriate daily dietary iron intake." Calarge et al., J Clin Psychiatry 2015 (PMID 26301448): longitudinal tracking of iron homeostasis against weight change following risperidone initiation or discontinuation in children and adolescents. Exact cohort sizes were not captured from the abstract summaries retrieved during this review; effect estimates are as reported above.

Mechanism

Not established as a single named biochemical pathway. The 2016 finding of low ferritin "despite appropriate dietary iron intake" argues against a simple absorption or intake deficit, and points instead toward increased iron utilization or sequestration, plausibly linked to risperidone-associated weight gain and the low-grade inflammatory state of metabolic syndrome (inflammation-driven hepcidin elevation is the leading hypothesis in this literature, though not directly measured in the cited papers).

Counter-evidence held on record

The "despite appropriate dietary iron intake" finding is itself the strongest argument against a dietary-cause explanation, and redirects toward a utilization or inflammatory mechanism. No study identified tested whether iron repletion improves any clinical outcome in this population. Do not supplement iron in a child or adolescent on risperidone without a lab-confirmed low ferritin or iron panel. Iron overload carries its own toxicity risk; any repletion dose should be prescriber-directed and kept under the NIH Office of Dietary Supplements tolerable upper intake level for elemental iron (40 mg/day for ages 1 to 13, 45 mg/day for ages 14 and up). This dossier makes no standing dosing recommendation.

Limits on what this shows

• Why no grade: Both conditions for ungraded status are met: no Tier B or Tier C evidence supports even a yellow grade for risperidone specifically, and no circulating claim was located naming risperidone and copper together for this review to rebut as white.

Channels tried

PubMed search-listing pages, multiple phrasings ("risperidone copper", "risperidone copper zinc serum", "antipsychotic copper serum schizophrenia"); Semantic Scholar Graph API (returned a 429 rate-limit response); Europe PMC REST API (blocked by session proxy, connect_rejected); Crossref API (blocked by session proxy, connect_rejected) during this specific review.

Outcome

Direct "risperidone copper" queries either returned no results or were blocked by session-level rate limiting before a clean result could be captured. A broader class-level query found copper elevation associated with the illness state of schizophrenia itself, not with any specific antipsychotic: Herran et al. 2000 (PMID 10788677, depot typical-neuroleptic cohort, not risperidone), Saghazadeh et al. 2020 (PMID 31800085, cross-drug meta-analysis of 39 studies), and Chen et al. 2018 (PMID 28470477, drugs not individually specified in the retrieved abstract). Under Hard Rule 6, confounding by indication is presumed until excluded; this illness-associated, non-drug-specific literature does not meet the bar for even a class-level yellow claim about risperidone's own pharmacological effect on copper, and if anything argues against attributing the association to the drug.

Genuine gap vs tooling limited

Assessed as substantially a genuine evidence gap for risperidone specifically, since the illness-association literature that does exist argues against, not for, a drug-attributable copper effect. This is compounded by a real tooling limitation: session-level rate limiting blocked Semantic Scholar, Europe PMC, and Crossref access, and blocked one direct PubMed attempt, preventing an exhaustive search from being fully completed at the time of this review. A future revision should re-attempt the blocked channels before treating this gap as fully closed.

Limits on what this shows

• Null/negative findings: Li et al., Brain Res 2023 (PMID 37598899) and Gokulakrishnan et al., J Psychiatr Res 2023 (PMID 37156128) describe microbiome differences in adult schizophrenia patients on antipsychotics generally without isolating risperidone's independent contribution from illness-associated dysbiosis; treated here as supportive context, not independent drug-specific confirmation.
• At-risk subgroups: Children and adolescents, and any patient with substantial risperidone-associated weight gain.

Regulatory status

Not addressed in the FDA label; this is investigational mechanistic literature, not a labeled effect.

Population evidence

Bahr et al., Transl Psychiatry 2015 (PMID 26440540): human pediatric patients newly started on risperidone; drug treatment and secondary weight gain were associated with altered gut microbiota composition. Companion mechanistic study, Bahr et al., EBioMedicine 2015 (PMID 26870798, mouse): risperidone-induced weight gain was mediated through gut microbiome shifts that suppressed host energy expenditure, a causal demonstration in the animal model. Ye et al., Microbiome 2026 (PMID 41761296, mouse): early risperidone exposure impaired cognition via gut microbiome perturbation and intestinal barrier changes, with fecal microbiota transplant used to demonstrate causality. Aboulalazm et al., Gut Microbes 2025 (PMID 40190120, mouse): depletion of a specific Limosilactobacillus reuteri -related metabolite contributed to risperidone-associated adverse metabolic effects.

Mechanism

Risperidone-associated shifts in gut microbial composition appear to suppress host energy expenditure and alter microbial metabolite signaling, mechanistically contributing to the drug's well-documented weight gain and metabolic-syndrome liability, per the mouse causal studies.

Counter-evidence held on record

The human evidence base for this specific pairing is a single pediatric cohort (Bahr 2015); confounding by baseline diet, illness-associated gastrointestinal differences, and concurrent medications was not fully excludable from the available abstract. Causal confirmation exists only in mice, not in humans. No probiotic strain or dose has clinical trial support for reversing this effect in risperidone-treated patients. Do not substitute probiotic supplementation for standard metabolic monitoring (weight, glucose, lipids).

Limits on what this shows

• Null/negative findings: No cohort or case-control study measuring hemoglobin or hematocrit in risperidone-treated patients was located.
• At-risk subgroups: Not established.

Regulatory status

The FDA label does not list anemia or hemoglobin/hematocrit change among labeled adverse reactions. Leukopenia, neutropenia, and agranulocytosis are listed as rare post-marketing hematologic adverse reactions, a distinct white-cell, immune-mediated phenomenon, not a red-cell or oxygen-carrying one.

Population evidence

National Medical Journal of India 2023 (PMID 37615136, human, case report): "Risperidone-induced anaemia," a single-patient case report. Full abstract text (dosing, hemoglobin values, dechallenge course) could not be retrieved due to a tooling access limitation at the time of this review; see Sources access notes.

Mechanism

Not established; case-report level only.

Counter-evidence held on record

The weight of the risperidone hematologic case-report literature concerns white-cell suppression (agranulocytosis, neutropenia, leukopenia; PMIDs 9619165, 22231329, 22984110, 28558630, 9373440, 11310398), not anemia. These are separate idiosyncratic immune-mediated adverse reactions and are intentionally not filed under this oxygen-delivery category. A single case report cannot establish causation. Do not attribute unexplained anemia in a risperidone-treated patient to the drug without first excluding standard causes, including the iron depletion documented in the Iron entry above.

Limits on what this shows

• Null/negative findings: No in vivo or human clinical energy-metabolism study was located.
• At-risk subgroups: Not established; the finding comes from a toxicological exposure range, not chronic therapeutic dosing.

Regulatory status

Not addressed in the FDA label.

Population evidence

Toxicol In Vitro 2024 (PMID 39237056, human peripheral blood monocytes, in vitro): risperidone decreased ATP production in isolated mitochondria at about 70 micromolar, roughly two to three orders of magnitude above typical therapeutic plasma levels of risperidone plus 9-hydroxyrisperidone.

Mechanism

Proposed as direct mitochondrial bioenergetic disruption at toxic concentrations. This entry shares its underlying source with Mitochondrial burden above; see Overlap map, not counted as independent confirmation.

Counter-evidence held on record

No clinical correlate, such as fatigue, exercise capacity, or lactate, has been studied in risperidone-treated patients specifically. Does not support ATP-support supplementation, such as coenzyme Q10 or creatine, in patients on standard therapeutic risperidone dosing.