Association Between Antipsychotic Medication Use and Dementia Risk in Patients With Schizophrenia or Schizoaffective Disorder.

OBJECTIVE: To determine the association between antipsychotic prescriptions and incident dementia in patients with schizophrenia or schizoaffective disorder. METHODS: In this retrospective cohort study, Cox Proportional hazard models estimated the association between antipsychotic prescriptions and incident dementia in participants ≥50 years of age with a schizophrenia/schizoaffective disorder diagnosis over 12 years. Confounding was controlled by E-balance. RESULTS: Cumulative dementia incidence was significantly greater among those with an antipsychotic prescription compared to those without (7.9% vs 5.5%, P < 0.0001). After controlling for confounding, antipsychotic prescriptions were associated with a 92% increased risk for dementia (HR = 1.92; 95% CI:1.13-3.27). This association was not significant among those aged ≥65 years. Antipsychotic prescription type (eg, first generation, yes or no) did not affect dementia risk but prescription number did. CONCLUSION: Antipsychotic prescriptions were associated with almost twice the incidence of dementia compared to patients without in those with schizophrenia/schizoaffective disorder.

Impact of Demographics and Insurance Coverage on Schizophrenia Treatment and Healthcare Resource Utilization Within an Integrated Healthcare System.

Purpose: Little is known about the impact of health disparities on antipsychotic treatment and healthcare resource utilization (HRU) among patients with schizophrenia. The objective of this analysis is to examine treatment patterns and HRU by age, race/ethnicity, and insurance coverage among patients with schizophrenia in an integrated delivery network (IDN). Patients and Methods: This cross-sectional study used electronic health record data from MedStar Health, an IDN in the Baltimore-Washington, DC, area. Patients were aged ≥18 years and had ≥2 outpatient encounters or ≥1 hospitalization with a diagnosis of schizophrenia between January 1, 2017 and March 31, 2021. Outcomes assessed included oral antipsychotic prescriptions, long-acting injectable antipsychotic (LAI) utilization, hospitalizations, emergency department (ED) visits, and outpatient visits. Analyses compared subgroups based on age, race/ethnicity (non-Hispanic Black, non-Hispanic White, and other), and type of insurance coverage at index (Medicare, Medicaid, and other) during 12 months of follow-up. Results: A total of 78.1% of patients had ≥1 prescription for an antipsychotic and 69.1% received ≥1 second-generation antipsychotic. Second-generation long-acting injectables (SGA LAI) were utilized by 9.0% of patients, with the elderly and Medicaid beneficiaries having the lowest SGA LAI utilization. Overall, 61.7% of patients had ≥1 hospitalization, 56.4% had ≥1 outpatient visit, and 50.5% had ≥1 ED visit. Hospitalizations and ED visits were most common in those 18 to 24 years of age and in Medicaid beneficiaries, whereas outpatient visits were more common for the elderly and Medicare beneficiaries. Conclusion: At the population level, the results indicate widespread underprescription/underutilization of antipsychotics that have been shown to improve clinical and economic outcomes in patients with schizophrenia, particularly SGA LAI. Within specific subpopulations, disparities in treatment selection and HRU were observed, suggesting the need for increased attention to at-risk groups to ensure consistent quality of care regardless of age, race/ethnicity, or insurance coverage.

Caudate nucleus volume in medicated and unmedicated patients with early- and adult-onset schizophrenia.

The caudate nucleus is a part of the striatum, and striatal hyperdopaminergia is considered central to the pathophysiology of schizophrenia. How caudate volume is affected in schizophrenia and what role antipsychotics play remains unclear. In early-onset schizophrenia (EOS), where psychosis emerges during a neurodevelopmentally critical phase, the caudate may exhibit a heightened vulnerability to the effects of antipsychotic medications. We hypothesized effects of both antipsychotic medication use and age of onset on caudate in schizophrenia. We included adult patients with EOS (n = 83) and adult-onset schizophrenia (AOS) (n = 246), adult healthy controls (HC, n = 774), adolescent patients with non-affective psychosis (n = 56) and adolescent HC (n = 97). We obtained T1-weighted MRI scans using a 1.5T Siemens scanner and General Electric 3T scanners. In our main analysis, we tested for main and interaction effects of diagnosis and current antipsychotic medication use on caudate volume. Adult patients with EOS (p < 0.001) and AOS (p = 0.002) had both larger caudate than HC. Age of onset (EOS/AOS) interacted with antipsychotic use (p = 0.004) which was associated with larger caudate in EOS (p < 0.001) but not in AOS (p = 0.654). Conversely, among medicated patients only, EOS had larger caudate than AOS (p < 0.001). No other subcortical structures showed differences between medicated EOS and AOS. Medicated adolescent patients with non-affective psychosis and medicated adult patients with EOS showed similar caudate volumes. The results may indicate a schizophrenia-related and a medication-induced caudate increase, the latter restricted to patients with EOS and possibly occurring already in adolescence shortly after disease onset.

Neonatal outcomes after in utero exposure to antipsychotics: a systematic review and meta-analysis.

Adverse neonatal outcomes following in utero antipsychotic exposure remain unclear. This systematic review and meta-analysis aimed to investigate associations between in utero first- and second-generation antipsychotic exposure and various neonatal outcomes. The primary outcome was small for gestational age. Secondary outcomes included other birth weight-related measures, prematurity and neonatal outcomes. MEDLINE, EMBASE, CENTRAL, ICTRP, and ClinicalTrials.gov were searched for on 8th July 2023. Two reviewers independently selected studies reporting associations between exposure and neonatal outcomes (all designs were eligible, no language or time restriction) and extracted data. ROBINS-I was used for risk of bias assessment. Meta-analyses were performed. Measures of association were odds ratios and mean differences. Thirty-one observational studies were included. Regarding small for gestational age < 10th percentile, meta-analysis was only performed for second-generation antipsychotics and showed no evidence for an association (OR 1.31 [95%CI 0.83; 2.07]; I²=46%; phet=0.13, n = 4 studies). First-generation antipsychotics were associated with an increased risk of small for gestational age < 3rd percentile (OR 1.37 [95%CI 1.02; 1.83]; I²=60%; phet=0.04, n = 5) and a lower mean birthweight (MD -135 g [95%CI -203; -66]; I²=53%; phet=0.07, n = 5). Second-generation antipsychotics were associated with large for gestational age > 97th percentile (OR 1.56 [95%CI 1.31; 1.87]; I²=4%; phet=0.37, n = 4) and Apgar score < 7 (OR 1.64 [95%CI 1.09; 2.47]; I²=47%; phet=0.13, n = 4). Both types of antipsychotics were associated with increased risks of preterm birth and neonatal hospitalization. Despite potential confounding in the studies, this systematic review and meta-analysis showed that newborns of mothers using antipsychotics during pregnancy are potentially at risk of adverse neonatal outcomes. Data sources: MEDLINE, EMBASE, CENTRAL, ICTRP, ClinicalTrials.gov. Prospero Registration Number CRD42023401805.

Psychiatrists' views on clozapine prescribing in Ireland.

INTRODUCTION: Despite proven effectiveness in refractory schizophrenia, clozapine remains underutilised, and it is important to understand potential reasons for this. This study's aim was to examine in a National sample of Consultant Psychiatrists their knowledge of, attitudes and perceived barriers to clozapine use. METHODS: A novel questionnaire was designed and distributed by email to 275 Consultant Psychiatrists in Republic of Ireland. RESULTS: Twenty-eight percent (n = 77) completed the survey, with 55% of respondents practicing for 15 or more years. Clinicians expressed confidence in managing clozapine treatment and side effects and were well aware of clozapine's clinical effectiveness and guideline-based use. A majority indicated insufficient experience managing rechallenge and half expressed insufficient experience managing adverse events. Perceived patient factors were highlighted as barriers with 69% of respondents reporting patients' concern about effectiveness and 50% regarding tolerability. Sixty-four percent (n = 40) indicated that a specialised/tertiary clozapine service would facilitate initiation, with 57% (n = 36) reporting less frequent blood monitoring would aid clozapine prescribing. A majority identified that access to dedicated staff (81%, n = 51) and dedicated day hospital services (84%, n = 53) would facilitate community initiation. CONCLUSION: Consultants are familiar with clozapine use and related guidelines. Dedicated staff and facilities for clozapine use is one identified structural change to enhance clozapine prescribing in Ireland. Tertiary service or clinical advice service would assist in clozapine rechallenge cases or in managing significant adverse events. More structured patient education regarding clozapine effectiveness and professional development programmes focused on managing side effects and rechallenge may promote clozapine use.

Successful Treatment of Risperidone-Induced Hypothermia With Aripiprazole: A Brief Case Report and a Literature Review.

Hypothermia, a potentially fatal condition, can result from various internal causes, including certain medications. Antipsychotics, in particular, are associated with hypothermia, typically emerging 7-10 days after dosage adjustments. Here, we report the case of a 68-year-old male with a history of cerebral palsy, bipolar disorder, and paranoid schizophrenia who was admitted due to poor oral intake and was found to have persistent hypothermia despite active external rewarming. After substituting risperidone with aripiprazole, his temperature normalized, and he experienced no further hypothermic episodes.  Antipsychotic-induced hypothermia should be considered in patients on these medications who present with non-specific symptoms. Regular monitoring of temperature and vital signs is crucial for early detection and management.

Association of antipsychotic formulations with sudden cardiac death in patients with schizophrenia: A nationwide population-based case-control study.

The aim of this study was to clarify the association between various antipsychotic formulations-oral-daily antipsychotics (OAPs), long-acting injectable antipsychotics (LAIs), and their combination-and the risk of sudden cardiac death (SCD). We conducted a nationwide population-based case-control study using data from 2011 to 2020 from the National Health Insurance Research Database and multiple-cause-of-death data from Taiwan. The study included patients with a new diagnosis of schizophrenia who were followed for SCD occurrence until 2020. Cases and controls were frequency-matched at a 1:4 ratio by age, sex, and year of new schizophrenia diagnosis. Compared with the use of OAP monotherapy, the use of LAI and OAP combination (OR = 1.91) and LAI monotherapy (OR = 1.45) were associated with an increased risk of SCD. Additionally, cardiovascular comorbidities (adjusted OR = 11.15) were identified as a significant risk factor for SCD. This study revealed the following hierarchy of SCD risk associated with antipsychotic formulations (listed from lowest to highest risk): nonuse of antipsychotics, OAP monotherapy, LAI monotherapy, and their combination. These findings underscore the importance of assessing cardiovascular disease history before LAIs are prescribed to patients with schizophrenia and indicate that physicians should avoid prescribing combined antipsychotics when using LAIs.

Adult and adolescent antipsychotic exposure increases delay discounting and diminishes behavioral flexibility in male C57BL/6 mice.

Second-generation antipsychotics are frequently prescribed to adolescents, but the long-term consequences of their use remain understudied. These medications work via monoamine neurotransmitter systems, especially dopamine and serotonin, which undergo considerable development and pruning during adolescence. Dopamine and serotonin are linked to a wide host of behaviors, including impulsive choice and behavioral plasticity. In a murine model of adolescent antipsychotic use, male C57BL/6 mice were exposed to either 2.5 mg/kg/day risperidone or 5 mg/kg/day olanzapine via drinking water from postnatal days 22-60. To determine whether the adolescent period was uniquely sensitive to antipsychotic exposure, long-term effects on behavior were compared to an equivalently exposed group of adults where mice were exposed to 2.5 mg/kg risperidone from postnatal days 101-138. Motor activity and body weight in adolescent animals were assessed. Thirty days after exposure terminated animal's behavioral flexibility and impulsive choice were assessed using spatial discrimination reversal and delay discounting. Antipsychotic exposure produced a modest change in behavior flexibility during the second reversal. There was a robust and reproducible difference in impulsive choice: exposed animals devalued the delayed alternative reward substantially more than controls. This effect was observed both following adolescent and adult exposure, indicating that an irreversible change in impulsive choice occurs regardless of the age of exposure.

Detailing Healthcare Claims Data Evidence of Extrapyramidal Symptoms in Medicaid Patients with Schizophrenia after Second-Generation Antipsychotic Medication Initiation.

Researchers have used elements of administrative healthcare claims data (e.g., diagnosis codes and medications) to calculate rates of extrapyramidal symptoms (EPS) in patients with schizophrenia who utilize second-generation antipsychotics (SGAs). However, a detailed description of claims-based EPS evidence has not been previously provided, which is the objective of the current study. This descriptive study, using 2016-2020 de-identified multi-state Medicaid administrative claims data, followed patients diagnosed with schizophrenia for 12 months after initiation of SGA therapy to identify and describe the first evidence of EPS. Time to EPS evidence was calculated and continuously-eligible patients were followed for an additional 12 months to examine EPS medication utilization and costs. Following SGA initiation, 13.6% (n = 2,288) of patients had evidence of EPS during the 12-month follow-up period. Mean time to first evidence of EPS after SGA initiation was 103.7 days (sd = 112.2, median = 58). For a majority of patients (n = 1,636, 71.5%), an EPS medication claim was the initial evidence of EPS, rather than an EPS diagnostic claim. Additionally, a quarter of patients (25.3%) in the EPS evidence cohort had a claim for an EPS medication on the same date as SGA initiation, possibly indicating prophylactic prescribing to prevent EPS development. Nearly 93% of those with EPS medication claims were treated with benztropine, while less than 2% received deutetrabenazine or valbenazine (indicated for tardive dyskinesia (TD)). Annual per patient EPS medication expenditures were $804 (sd = 7,080) overall, but only $40 (sd = 104) when excluding the higher-cost TD medications. Nearly 14% of Medicaid patients with schizophrenia who initiated SGA treatment had evidence of EPS based on claims data. The majority of the time, this evidence was derived from a prescription claim for a medication to treat EPS, rather than an EPS diagnostic claim. Prophylactic prescribing for EPS occurred more often than expected and should be explored more fully. While the cost of traditional EPS medications minimally contributes to the overall cost of care in schizophrenia, use of newer TD drugs can substantially increase spending.

Incidence of Neuroleptic Malignant Syndrome During Antipsychotic Treatment in Children and Youth: A National Cohort Study.

Objective: The incidence of neuroleptic malignant syndrome (NMS), a rare, potentially fatal adverse effect of antipsychotics, among children and youth is unknown. This cohort study estimated NMS incidence in antipsychotic users age 5-24 years and described its variation according to patient and antipsychotic characteristics. Methods: We used national Medicaid data (2004-2013) to identify patients beginning antipsychotic treatment and calculated the incidence of NMS during antipsychotic current use. Adjusted hazard ratios (HRs) assessed the independent contribution of patient and antipsychotic characteristics to NMS risk. Results: The 1,032,084 patients had 131 NMS cases during 1,472,558 person-years of antipsychotic current use, or 8.9 per 100,000 person-years. The following five factors independently predicted increased incidence: age 18-24 years (HR [95% CI] = 2.45 [1.65-3.63]), schizophrenia spectrum and other psychotic disorders (HR = 5.86 [3.16-10.88]), neurodevelopmental disorders (HR = 7.11 [4.02-12.56]), antipsychotic dose >200mg chlorpromazine-equivalents (HR = 1.71 [1.15-2.54]), and first-generation antipsychotics (HR = 4.32 [2.74-6.82]). NMS incidence per 100,000 person-years increased from 1.8 (1.1-3.0) for those with none of these factors to 198.1 (132.8-295.6) for those with 4 or 5 factors. Findings were essentially unchanged in sensitivity analyses that restricted the study data to second-generation antipsychotics, children age 5-17 years, and the 5 most recent calendar years. Conclusion: In children and youth treated with antipsychotics, five factors independently identified patients with increased NMS incidence: age 18-24 years, schizophrenia spectrum and other psychotic disorders, neurodevelopmental disorders, first-generation drugs, and antipsychotic doses greater than 200 mg chlorpromazine-equivalents. Patients with 4 or 5 of these factors had more than 100 times the incidence of those with none. These findings could improve early identification of children and youth with elevated NMS risk, potentially leading to earlier detection and improved outcomes.

Clozapine, relapse, and adverse events: a 10-year electronic cohort study in Canada.

BACKGROUND: Clozapine is the most effective medication for treatment-resistant psychoses, but the balance of benefits and risks is understudied in real-world settings. AIMS: To examine the relative re-hospitalisation rates for mental health relapse and adverse events associated with clozapine and other antipsychotics in adult and child/youth cohorts. METHOD: Data were obtained from the Canadian Institute of Health Information for adults (n = 45 616) and children/youth (n = 1476) initially hospitalised for mental health conditions in British Columbia, Manitoba and Saskatchewan from 2008 to 2018. Patient demographics and hospitalisations were linked with antipsychotic prescriptions dispensed following the initial visit. Recurrent events survival analysis for relapse and adverse events were created and compared between clozapine and other antipsychotics. RESULTS: In adults, clozapine was associated with a 14% lower relapse rate versus other drugs (adjusted hazard ratio: 0.86, 95% CI: 0.83-0.90) over the 10-year follow-up. In the first 21 months, the relapse rate was higher for clozapine but then reversed. Over 1000 person-months, clozapine-treated adults could be expected to have 38 relapse hospitalisations compared with 45 for other drugs. In children/youth, clozapine had a 38% lower relapse rate compared with other antipsychotic medications (adjusted hazard ratio: 0.62, 95% CI: 0.49-0.78) over the follow-up period. This equates to 29 hospitalisations for clozapine and 48 for other drugs over 1000 person-months. In adults, clozapine had a higher risk for adverse events (hazard ratio: 1.34, 95% CI: 1.18-1.54) over the entire follow-up compared with other antipsychotics. This equates to 1.77 and 1.30 hospitalisations over 1000 person-months for clozapine and other drugs, respectively. CONCLUSIONS: Clozapine was associated with lower relapse overall, but this was accompanied by higher adverse events for adults. For children/youth, clozapine was associated with lower relapse all throughout and had no difference in adverse events compared with other antipsychotics.

Clinical challenges in the dosing and titration of cariprazine.

The introduction of a new psychopharmaceutical medication instead of the previous one always poses a certain challenge. In the case of antipsychotics (AP), these problems are considerably more complicated and are mainly caused by the question of dose equivalents, but also by the pharmacokinetic properties of the drug. In the case of partial dopamine D2 agonists, an additional issue is the possibility of deterioration when switching from the previous D2 antagonists to these drugs. Cross-titration is therefore generally recommended. Finally, due to the capsule form, it is not possible to increase the dose of cariprazine by less than 1.5 mg during titration. In this paper, we have presented our proposal to replace the most commonly used second-generation APs with the third-generation AP cariprazine. We have taken into account the dose equivalents, the pharmacological forms of the drugs and their pharmacokinetic and pharmacodynamic properties.

The Putative Link Between Omodysplasia and Treatment-Resistant Schizophrenia: A Complex Clinical Presentation of a Rare Genetic Disorder.

Genetic and metabolic disorders present unique challenges in understanding the pathophysiology and outcomes of specific symptoms and presentations due to their broad spectrum of manifestations and etiologies. In this case report, we have studied a 26-year-old who was diagnosed with omodysplasia, a rare form of skeletal dysplasia. She exhibits atypical symptoms of psychosis and was diagnosed with schizophreniform disorder at an early age. Various antipsychotic medications were administered; however, minimal to no improvement was noted in the symptoms. On the contrary, she reported adverse effects to some antipsychotics. She continued to exhibit delusions and hallucinations and showed clinical improvement after treatment with olanzapine. Her clinical course was further complicated by the presence of borderline personality traits, which went unnoticed earlier. Here, we would like to highlight the course of her symptoms, the different treatments administered, and the possible link between omodysplasia and treatment-resistant schizophrenia.

The relationship between self-reported antipsychotics side effects and depression in Saudi Arabia.

Background: The utilization rate of antipsychotics to treat different mental disorders is rising. However, little is known about their side effects' impact on depression levels. Therefore, the objective of this study was to examine the association between antipsychotic side effects and depression among psychiatric patients treated with antipsychotics. Methods: This is a prospective, single-center, interview-based, cross-sectional study that examined the association between antipsychotic side effects and depression among adult patients (e.g., ≥18 yrs.) with psychiatric illnesses (e.g., depression, schizophrenia, bipolar disorder) visiting outpatient clinics in a university-affiliated tertiary care center. Antipsychotic side effects were assessed using the Arabic version of the Glasgow Antipsychotic Side-effect Scale (GASS), while depression was assessed using the Arabic version of the 9-item Patient Health Questionnaire (PHQ-9). Univariate and multiple linear regressions were conducted to examine the association between the PHQ-9 and GASS scores. Results: One hundred patients met the inclusion criteria and consented to participate. Most of the patients were females (72 %) with a mean age of 38 years. Schizophrenia (37 %) and bipolar disorder (54 %) were the most common mental disorders among the recruited patients. The majority of patients were treated with atypical (e.g., second-generation) antipsychotics (88 %) for at least six months (74 %). Controlling for age, gender, annual family income, education, employment status, marital status, number of comorbidities, duration of treatment with antipsychotics, the type of antipsychotic, and psychiatric illness, higher GASS scores, which indicate more severe antipsychotic side effects, predicted higher PHQ-9 score (e.g., higher levels of depression) (ß = 0.419, 95 % CI=[0.307-0.532], p-value < 0.0001). Conclusion: Early identification and management of antipsychotic side effects among psychiatric patients should enhance patient adherence and improve treatment outcomes. Future studies should verify the findings of this study using more robust study designs.

Psychopharmacotherapy of Pica-How Much Do We Know?

There is little evidence for psychopharmacotherapy in pica. A few studies reported some benefit from the use of SSRIs, atypical antipsychotics and methylphenidate. That said, evidence to deploy these agents remains, at large, flimsy. Here, despite scarcity, we review available literature and draw some generalities that can inform decision-making on clinical grounds.

Metabolic Syndrome among Patients Taking Atypical Antipsychotics: A Comparative Cross-Sectional Study at Erada and Mental Health Complex in Taif, Saudi Arabia.

Introduction: Second-Generation Antipsychotics (SGAs) are widely used for treating psychiatric disorders due to their favorable side effect profile compared to First-Generation Antipsychotics (FGAs). However, SGAs are associated with significant metabolic side effects. This study aims to explore the sociodemographic and health differences between individuals using SGAs and those not using them. Methods: A comparative cross-sectional study was conducted with 148 participants, including 102 SGA users and 46 non-users. Data were collected from patients and medical records, encompassing sociodemographic factors and health variables including diabetes mellitus, hypertension, cardiovascular disease, hyperlipidemia, waist circumference, fasting blood glucose, cholesterol, triglycerides, HDL, LDL, and BMI. Statistical analyses included chi-square and Fisher's exact tests to compare the two groups. Results: SGA users had higher rates of overweight and obesity compared to non-users (p = 0.000), with 30.4% overweight and 29.4% obese among SGA users versus 21.7% overweight and 4.3% obese among non-users. A higher prevalence of cardiovascular disease was observed in SGA users (11.8% vs. 2.2%, p = 0.076). Although not statistically significant, trends indicated higher rates of diabetes mellitus and hyperlipidemia in non-users (30.4% vs. 18.6%, p = 0.110 and 7% vs. 0%, p = 0.083, respectively). Conclusion: This study highlights significant differences in BMI and cardiovascular disease prevalence between SGA users and non-users, reinforcing the need for comprehensive metabolic monitoring in patients treated with SGAs. The findings underscore the importance of considering sociodemographic factors in managing the health risks associated with SGA use. Further research with larger sample sizes and longitudinal designs is warranted to better understand these associations and develop targeted interventions.

Distinguishing Reality: A Case of Delusional Misidentification Syndrome in a 39-Year-Old Male.

Capgras syndrome (CS) is a type of delusional misidentification syndrome where an individual is under the impression that a person they know has been switched with an identical imposter. One theory for the development of CS is a disturbance among the frontal, limbic, and temporal areas, which creates an alteration in an individual's ability to recognize a person's face and provoke a response emotionally. The primary risk factors for the development of CS include having a neurological disorder and a diagnosis of schizophrenia. We present a case of a 39-year-old male with a past medical history of traumatic brain injury and familial history of schizophrenia who presented to the Emergency Department with paranoia and the belief that his father had been switched with an imposter. After ruling out organic causes, he was stabilized on olanzapine before discharge to outpatient follow-up. This case highlights the importance of prompt recognition of the symptomatology associated with CS and treatment with olanzapine for a favorable outcome.

Antipsychotic medication in people with intellectual disability and schizophrenia: A 25-year updated systematic review and cross-sectional study.

OBJECTIVES: To determine the efficacy and safety of antipsychotic medication for treating individuals with a dual diagnosis of intellectual disability (ID) and schizophrenia. METHODS: We systematically reviewed the literature to explore the risks and benefits of antipsychotics for schizophrenia in ID. In addition, a cross-sectional retrospective study on the tolerance profiles of a representative ID and schizophrenia cohort was conducted. RESULTS: From the systematic search, we retained 18 articles detailing information on 24 cases. In almost all cases, the antipsychotic improved psychotic symptoms (e.g., hallucinations, delusions, disorganization). Negative manifestations were also improved (blunted affects, amotivation, poor rapport), as were challenging behaviors in a few cases. The most commonly reported side effects were neurological (extra-pyramidal, movement disorder, epilepsy) and metabolic manifestations. In the retrospective cross-sectional study, we reported data on 112 participants with comorbid ID and schizophrenia. In all, 103 participants were antipsychotic-treated, of which 39% were on antipsychotic monotherapy. Of these, 35% were in the obesity range, 25% in the hyperglycemic range, and 25% in the dyslipidemia range. The body mass index did not differ between the groups. CONCLUSIONS: This study provides an initial evidence base underpinning the efficacy of antipsychotic drugs on schizophrenia in the ID population. Nevertheless, there may be an increased risk of metabolic side effects, hence, close monitoring of blood glucose, lipids, and weight should be implemented when prescribing antipsychotics to this population.