Challenges and complexities in designing cluster headache prevention clinical trials: A narrative review.

OBJECTIVE: To provide a review of challenges in clinical trials for the preventive treatment of cluster headache (CH) and highlight considerations for future studies. BACKGROUND: Current guidelines for preventive treatment of CH are largely based on off-label therapies supported by a limited number of small randomized controlled trials. Guidelines for clinical trial design for CH treatments from the International Headache Society were last issued in 1995. METHODS/RESULTS: Randomized controlled clinical trials were identified in the European and/or United States clinical trial registries with a search term of "cluster headache," and manually reviewed. Cumulatively, there were 27 unique placebo-controlled prevention trials for episodic and/or chronic CH, of which 12 were either ongoing, not yet recruiting, or the status was unknown. Of the remaining 15 trials, 5 were terminated early and 7 of the 10 completed trials enrolled fewer patients than planned or did not report the planned sample size. A systematic search of PubMed was also utilized to identify published manuscripts reporting results from placebo-controlled preventive trials of CH. This search yielded 16 publications, of which 7 were registered. Through critical review of trial data and published manuscripts, challenges and complexities encountered in clinical trials for the preventive treatment of CH were identified. For example, the excruciating pain associated with CH demands a suitably limited baseline duration, rapid treatment efficacy onset, and poses a specific issue regarding duration of investigational treatment period and length of exposure to placebo. In episodic CH, spontaneous remission as part of natural history, and the unpredictability and irregularity of cluster periods across patients present additional key challenges. CONCLUSIONS: Optimal CH trial design should balance sound methodology to demonstrate efficacy of a potential treatment with patient needs and the natural history of the disease, including unique outcome measures and endpoint timings for chronic versus episodic CH.

Secondary Fracture Prevention: Consensus Clinical Recommendations from a Multistakeholder Coalition.

Osteoporosis-related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fractureamong people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, andsubcutaneous pharmacotherapies are efficaciousandcanreduce risk of future fracture.Patientsneededucation,however, about thebenefitsandrisks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first-line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive butmay be beneficial for selected patients at high risk.Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the earlypost-fractureperiod,prompt treatment is recommended.Adequate dietary or supplemental vitaminDand calciumintake shouldbe assured. Individuals beingtreatedfor osteoporosis shouldbe reevaluated for fracture risk routinely, includingvia patienteducationabout osteoporosisandfracturesandmonitoringfor adverse treatment effects.Patients shouldbestronglyencouraged to avoid tobacco, consume alcohol inmoderation atmost, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease).

Phase 3 randomized, placebo-controlled study of galcanezumab in patients with chronic cluster headache: Results from 3-month double-blind treatment.

OBJECTIVE: To report efficacy and safety of galcanezumab in adults with chronic cluster headache. BACKGROUND: Galcanezumab is a humanized monoclonal antibody that binds to calcitonin gene-related peptide and inhibits its biological activity. METHODS: This study comprised a prospective baseline period, a 12-week double-blind, placebo-controlled treatment period, and a 52-week open-label period. Up to six protocol-specified concomitant preventive medications were allowed if patients were on a stable dose for 2 months prior to the prospective baseline period. Patients were randomized 1:1 to monthly subcutaneous galcanezumab (300 mg) or placebo. The primary endpoint was overall mean change from baseline in weekly attack frequency with galcanezumab compared to placebo. Key secondary endpoints were ≥50% response rate and percentage of patients meeting sustained response. Results from the double-blind treatment period are reported. RESULTS: A total of 237 patients were randomized and treated (120 placebo; 117 galcanezumab). At baseline, the mean age was 45 years and 63% were using ≥1 preventive drug. The primary endpoint was not met; mean change in weekly attack frequency was -4.6 placebo versus -5.4 galcanezumab (p = 0.334). Key secondary endpoints also were not met. Injection site-related treatment-emergent adverse events were more common in the galcanezumab than the placebo group, with significantly more injection site erythema. CONCLUSION: Treatment with galcanezumab 300 mg did not achieve its primary and key secondary endpoints. This study underscores the potential distinct biology of cCH as well as the significant unmet need for safe, effective, and well-tolerated preventive treatment. The safety profile of galcanezumab in cCH is consistent with that observed in trials of episodic CH and migraine. TRIAL REGISTRATION: NCT02438826; https://www.clinicaltrials.gov/ct2/show/NCT02438826.

Secondary Fracture Prevention: Consensus Clinical Recommendations from a Multistakeholder Coalition.

Osteoporosis-related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fracture among people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, and subcutaneous pharmacotherapies are efficacious and can reduce risk of future fracture. Patients need education, however, about the benefits and risks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first-line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive but may be beneficial for selected patients at high risk. Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the early post-fracture period, prompt treatment is recommended. Adequate dietary or supplemental vitamin D and calcium intake should be assured. Individuals being treated for osteoporosis should be reevaluated for fracture risk routinely, including via patient education about osteoporosis and fractures and monitoring for adverse treatment effects. Patients should be strongly encouraged to avoid tobacco, consume alcohol in moderation at most, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease). © 2019 American Society for Bone and Mineral Research.

Trial of Galcanezumab in Prevention of Episodic Cluster Headache.

BACKGROUND: Episodic cluster headache is a disabling neurologic disorder that is characterized by daily headache attacks that occur over periods of weeks or months. Galcanezumab, a humanized monoclonal antibody to calcitonin gene-related peptide, may be a preventive treatment for cluster headache. METHODS: We enrolled patients who had at least one attack every other day, at least four total attacks, and no more than eight attacks per day during a baseline assessment, as well as a history of cluster headache periods lasting at least 6 weeks, and randomly assigned them to receive galcanezumab (at a dose of 300 mg) or placebo, administered subcutaneously at baseline and at 1 month. The primary end point was the mean change from baseline in the weekly frequency of cluster headache attacks across weeks 1 through 3 after receipt of the first dose. The key secondary end point was the percentage of patients who had a reduction from baseline of at least 50% in the weekly frequency of cluster headache attacks at week 3. Safety was also assessed. RESULTS: Recruitment was halted before the trial reached the planned sample size of 162 because too few volunteers met the eligibility criteria. Of 106 enrolled patients, 49 were randomly assigned to receive galcanezumab and 57 to receive placebo. The mean (±SD) number of cluster headache attacks per week in the baseline period was 17.8±10.1 in the galcanezumab group and 17.3±10.1 in the placebo group. The mean reduction in the weekly frequency of cluster headache attacks across weeks 1 through 3 was 8.7 attacks in the galcanezumab group, as compared with 5.2 in the placebo group (difference, 3.5 attacks per week; 95% confidence interval, 0.2 to 6.7; P = 0.04). The percentage of patients who had a reduction of at least 50% in headache frequency at week 3 was 71% in the galcanezumab group and 53% in the placebo group. There were no substantial between-group differences in the incidence of adverse events, except that 8% of the patients in the galcanezumab group had injection-site pain. CONCLUSIONS: Galcanezumab administered subcutaneously at a dose of 300 mg once monthly reduced the weekly frequency of attacks of episodic cluster headache across weeks 1 through 3 after the initial injection, as compared with placebo. (Funded by Eli Lilly; ClinicalTrials.gov number, NCT02397473.).

Evaluation of Galcanezumab for the Prevention of Episodic Migraine: The EVOLVE-1 Randomized Clinical Trial.

Importance: Migraine is a disabling neurological disease characterized by severe headache attacks. Treatment options reduce migraine frequency for many patients, but adverse effects lead to discontinuation in many patients. Objective: To demonstrate that galcanezumab is superior to placebo in the prevention of episodic migraine with or without aura. Design, Setting, and Participants: The EVOLVE-1 (Evaluation of LY2951742 in the Prevention of Episodic Migraine 1) trial was a double-blind, randomized, placebo-controlled (January 11, 2016, to March 22, 2017) trial comparing galcanezumab (120 mg and 240 mg) vs placebo. Patients received treatments once monthly for 6 months (subcutaneous injection via prefilled syringe) and were followed up for 5 months after their last injection. It was a multicenter, clinic-based study involving 90 sites in North America. Participants in the study were adults (aged 18 to 65 years) with at least a 1-year history of migraine, 4 to 14 migraine headache days per month and a mean of at least 2 migraine attacks per month within the past 3 months, and were diagnosed prior to age 50 years. During the study, no other preventive medications were allowed. A total of 1671 patients were assessed; 809 did not meet study entry or baseline criteria, and 858 were included in the intent-to-treat population. Interventions: Patients were randomized (2:1:1) to monthly placebo, galcanezumab, 120 mg, and galcanezumab, 240 mg. Main Outcomes and Measures: The primary outcome was overall mean change from baseline in the number of monthly migraine headache days during the treatment period. Secondary measures included at least 50%, at least 75%, and 100% reduction in monthly migraine headache days, migraine headache days with acute medication use, and scores from the Migraine-Specific Quality of Life questionnaire, Patient Global Impression of Severity, and Migraine Disability Assessment. Treatment-emergent adverse events and serious adverse events were reported. Results: Of the 1671 patients assessed, 858 (mean age, 40.7 years; 718 women [83.7%]) met study entry criteria and received at least 1 dose of investigational product. The primary objective was met for both galcanezumab doses; treatment with galcanezumab significantly reduced monthly migraine headache days (both P < .001) by 4.7 days (120 mg) and 4.6 days (240 mg) compared with placebo (2.8 days). All key secondary objectives were also significant after multiplicity adjustment. There were no meaningful differences between 120-mg and 240-mg doses of galcanezumab on measures of efficacy. Completion rate during treatment was high (81.9%; n = 718), and the incidence of discontinuation owing to adverse events was less than 5% across all treatment groups. Conclusions and Relevance: Galcanezumab 120-mg and 240-mg monthly injections provided clinical benefits and improved functioning. The incidence rate of adverse events was low, demonstrating the favorable tolerability profile of galcanezumab. Trial Registration: ClinicalTrials.gov Identifier: NCT02614183.

Improvements in Tritrichomonas foetus molecular testing.

Bovine trichomoniasis is a sexually transmitted disease that results in infertility, abortion, and calf age variability. To date, management strategies include testing for Tritrichomonas foetus and culling of infected males. Challenges associated with testing include cost of culture medium, time and labor burden of sample incubation and processing, and adverse effects of bacterial growth on detection sensitivity. To overcome these challenges, we developed a direct reverse-transcription quantitative real-time PCR (direct RT-qPCR) utilizing smegma, eliminating the use of culture medium. In an analysis of 166 field samples (56 positives and 110 negatives as determined using microscopic reading of cultures as the reference test), the direct RT-qPCR exhibited 100% diagnostic sensitivity and 100% specificity, whereas the currently employed qPCR (culture qPCR), which utilizes cultured samples, exhibited 95% diagnostic sensitivity and 100% specificity. Agreement between direct RT-qPCR and culture qPCR was 98%. Moreover, direct RT-qPCR identified 3 more positive samples and exhibited lower quantification cycle (Cq) values among positives by culture reading than did culture qPCR (direct RT-qPCR Cq range = 14.6-32.3 vs. culture qPCR Cq range = 18.7-37.4). The direct RT-qPCR enables simplified sample collection, elimination of culture medium, faster results, applicability in cows, and lower cost than culture qPCR.

Core Clinical Data Elements for Cancer Genomic Repositories: A Multi-stakeholder Consensus.

The Center for Medical Technology Policy and the Molecular Evidence Development Consortium gathered a diverse group of more than 50 stakeholders to develop consensus on a core set of data elements and values essential to understanding the clinical utility of molecularly targeted therapies in oncology.

Pharmacogenomic associations with weight gain in olanzapine treatment of patients without schizophrenia.

OBJECTIVE: Pharmacogenomic analyses of weight gain during treatment with second-generation antipsychotics have resulted in a number of associations with variants in ankyrin repeat and kinase domain containing 1 (ANKK1)/dopamine D2 receptor (DRD2) and serotonin 2C receptor (HTR2C) genes. These studies primarily assessed subjects with schizophrenia who had prior antipsychotic exposure that may have influenced the amount of weight gained from subsequent therapies. We assessed the relationships between single-nucleotide polymorphisms (SNPs) in these genes with weight gain during treatment with olanzapine in a predominantly antipsychotic-naive population. METHOD: The association between 5 ANKK1, 54 DRD2, and 11 HTR2C SNPs and weight change during 8 weeks of olanzapine treatment was assessed in 4 pooled studies of 205 white patients with diagnoses other than schizophrenia who were generally likely to have had limited previous antipsychotic exposure. RESULTS: The A allele of DRD2 rs2440390(A/G) was associated with greater weight gain in the entire study sample (P = .0473). Three HTR2C SNPs in strong linkage disequilibrium, rs6318, rs2497538, and rs1414334, were associated with greater weight gain in women but not in men (P = .0032, .0012, and .0031, respectively). A significant association with weight gain for 2 HTR2C SNPs previously reported associated with weight gain, -759C/T (rs3813929) and -697G/C (rs518147), was not found. CONCLUSIONS: Associations between weight gain and HTR2C and DRD2 variants in whites newly exposed to olanzapine may present opportunities for the individualization of medication selection and development based on differences in adverse events observed across genotype groups.

Antipsychotic monotherapy among outpatients with schizophrenia treated with olanzapine or risperidone in Japan: a health care database analysis.

PURPOSE: Antipsychotic monotherapy is often recommended over antipsychotic polypharmacy because of fewer adverse events, reduced treatment complexity, and lower medication cost. This study compared the rate and the duration of antipsychotic monotherapy following initiation of olanzapine or risperidone in the treatment of outpatients with schizophrenia in Japan. METHODS: Outpatients diagnosed with schizophrenia in the Japan Medical Data Center database were identified using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, diagnosis codes. Patients were between 20 and 65 years old, initiated on olanzapine or risperidone therapy between August 2003 and July 2008, and continuously enrolled during the 6 months prior to and the 12 months following the initiation date. Antipsychotic polypharmacy was defined as concurrent use of two or more antipsychotics. The probability of monotherapy during the 12-month follow-up period was assessed using a propensity score-adjusted generalized estimating equation model. Duration of monotherapy was contrasted using a propensity score-adjusted bootstrapping model. RESULTS: After applying all inclusion and exclusion criteria, the final analytic sample consisted of 332 olanzapine- and 496 risperidone-treated outpatients. At treatment initiation, 61.5% of the olanzapine-treated patients and 45.6% of the risperidone-treated patients received antipsychotic monotherapy (P < 0.001). After correcting for background differences, monotherapy was more common among olanzapine-treated patients (P = 0.001). In addition, olanzapine was used as monotherapy for a longer duration (P = 0.006). CONCLUSION: Consistent with prior global research, this retrospective naturalistic study of schizophrenia outpatients in Japan found that olanzapine is more likely to be used as monotherapy and to be used as monotherapy for a longer duration than risperidone.

Dopamine pathology in schizophrenia: analysis of total and phosphorylated tyrosine hydroxylase in the substantia nigra.

INTRODUCTION: Despite the importance of dopamine neurotransmission in schizophrenia, very few studies have addressed anomalies in the mesencephalic dopaminergic neurons of the substantia nigra/ventral tegmental area (SN/VTA). Tyrosine hydroxylase (TH) is the rate-limiting enzyme for the production of dopamine, and a possible contributor to the anomalies in the dopaminergic neurotransmission observed in schizophrenia. OBJECTIVES: In this study, we had three objectives: (1) Compare TH expression (mRNA and protein) in the SN/VTA of schizophrenia and control postmortem samples. (2) Assess the effect of antipsychotic medications on the expression of TH in the SN/VTA. (3) Examine possible regional differences in TH expression anomalies within the SN/VTA. METHODS: To achieve these objectives three independent studies were conducted: (1) A pilot study to compare TH mRNA and TH protein levels in the SN/VTA of postmortem samples from schizophrenia and controls. (2) A chronic treatment study was performed in rodents to assess the effect of antipsychotic medications in TH protein levels in the SN/VTA. (3) A second postmortem study was performed to assess TH and phosphorylated TH protein levels in two types of samples: schizophrenia and control samples containing the entire rostro-caudal extent of the SN/VTA, and schizophrenia and control samples containing only mid-caudal regions of the SN/VTA. RESULTS AND CONCLUSION: Our studies showed impairment in the dopaminergic system in schizophrenia that could be mainly (or exclusively) located in the rostral region of the SN/VTA. Our studies also showed that TH protein levels were significantly abnormal in schizophrenia, while mRNA expression levels were not affected, indicating that TH pathology in this region may occur posttranscriptionally. Lastly, our antipsychotic animal treatment study showed that TH protein levels were not significantly affected by antipsychotic treatment, indicating that these anomalies are an intrinsic pathology rather than a treatment effect.

Cost-effectiveness of several atypical antipsychotics in orally disintegrating tablets compared with standard oral tablets in the treatment of schizophrenia in the United States.

OBJECTIVE: Although the use of innovative drug delivery systems, like orally disintegrating antipsychotic tablets (ODT), may facilitate medication adherence and help reduce the risk of relapse and hospitalization, no information is available about the comparative cost-effectiveness of standard oral tablets (SOT) vs ODT formulations in the treatment of schizophrenia. This study compared the cost-effectiveness of olanzapine ODT and olanzapine SOT in the usual treatment of outpatients with schizophrenia from a US healthcare perspective. The study also compared olanzapine ODT with risperidone and aripiprazole, two other atypical antipsychotics available in both ODT and SOT formulations. METHODS: Published medical literature and a clinical expert panel were used to populate a 1-year Monte Carlo Micro-simulation model. The model captures clinical and cost parameters including adherence levels, treatment discontinuation by reason, relapse with and without inpatient hospitalization, quality-adjusted life years (QALYs), treatment-emergent adverse events, healthcare resource utilization, and associated costs. Key outcomes were total annual direct cost per treatment, QALY, and incremental cost-effectiveness (ICER) per 1 QALY gained. RESULTS: Based on model projections, olanzapine ODT therapy was more costly ($9808 vs $9533), but more effective in terms of a lower hospitalization rate (15% vs 16%) and better QALYs (0.747 vs 0.733) than olanzapine SOT therapy. Olanzapine ODT was more cost-effective than olanzapine SOT (ICER: $19,643), more cost-effective than risperidone SOT therapy (ICER: $39,966), and dominant (meaning less costly and more effective) than risperidone ODT and aripiprazole in ODT or SOT formulations. LIMITATIONS: Lack of head-to-head randomized studies comparing the three studied atypical antipsychotics required making input assumptions that need further study. CONCLUSIONS: This micro-simulation found that the utilization of olanzapine ODT for the treatment of schizophrenia is predicted to be more cost-effective than any other ODT or SOT formulations of the studied atypical antipsychotic medications.

Analysis of gene variants previously associated with iloperidone response in patients with schizophrenia who are treated with risperidone.

OBJECTIVE: We examined 6 single nucleotide polymorphisms (SNPs) previously reported to be associated with response to iloperidone therapy for association with response to risperidone therapy. METHOD: Patients with schizophrenia (DSM-IV) were assessed during 2006 and 2007 for response/nonresponse (defined as ≥ 20%/<20% improvement in Positive and Negative Syndrome Scale [PANSS] total score) after 2 weeks of risperidone treatment (2 to 6 mg/d). Responders continued risperidone treatment; nonresponders were randomly assigned to either risperidone or olanzapine treatment (10 to 20 mg/d) for an additional 10 weeks. Associations between change in PANSS total (primary outcome measure), positive, and negative scores and the 6 SNPs were examined in risperidone-treated patients (N = 145). Genotype frequencies and improvement in PANSS total scores were analyzed for those SNPs significantly associated with change in PANSS total score. RESULTS: The SNPs XKR4 rs9643483 and GRIA4 rs2513265 were significantly associated with change in PANSS total response (adjusted P < .05 for both), with the same direction of effect as reported for iloperidone. For patients with nonresponsive genotypes for these SNPs, mean improvement in PANSS total score for African Americans was two-thirds that seen for whites (XKR4: -13.9 versus -21.4; GRIA4: -12.5 versus -20.9). CONCLUSIONS: In this retrospective pharmacogenomic analysis, we found that 2 SNPs previously linked to iloperidone response were also associated with response to risperidone. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00337662.

Rimonabant for neurocognition in schizophrenia: a 16-week double blind randomized placebo controlled trial.

OBJECTIVE: To examine the effect of rimonabant on neurocognitive impairments in people with schizophrenia. METHODS: Participants entered a 16-week double-blind, placebo-controlled, randomized clinical trial. A neurocognitive battery was administered at baseline and end of study. RESULTS: In comparison to rimonabant (20mg/day), placebo-treated participants exhibited a significant improvement on the Repeatable Battery for the Assessment of Neuropsychological Status total score. In contrast, rimonabant was associated with significant improvement on a probabilistic learning task. There were no other significant treatment effects. CONCLUSIONS: Rimonabant did not improve global cognitive functioning, but did improve a specific learning deficit based on response to positive feedback.

Proinflammatory cytokines in the prefrontal cortex of teenage suicide victims.

Teenage suicide is a major public health concern, but its neurobiology is not well understood. Proinflammatory cytokines play an important role in stress and in the pathophysiology of depression-two major risk factors for suicide. Cytokines are increased in the serum of patients with depression and suicidal behavior; however, it is not clear if similar abnormality in cytokines occurs in brains of suicide victims. We therefore measured the gene and protein expression levels of proinflammatory cytokines interleukin (IL)-1ß, IL-6, and tissue necrosis factor (TNF)-α in the prefrontal cortex (PFC) of 24 teenage suicide victims and 24 matched normal control subjects. Our results show that the mRNA and protein expression levels of IL-1ß, IL-6, and TNF-α were significantly increased in Brodmann area 10 (BA-10) of suicide victims compared with normal control subjects. These results suggest an important role for IL-1ß, IL-6, and TNF-α in the pathophysiology of suicidal behavior and that proinflammatory cytokines may be an appropriate target for developing therapeutic agents.

Striatal mitochondria in subjects with chronic undifferentiated vs. chronic paranoid schizophrenia.

Schizophrenia (SZ) is a heterogeneous disease with a spectrum of symptoms, risk factors, and etiology. Abnormalities in mitochondria, the energy-producing organelles of the cell, have been observed in mixed cohorts of subjects with SZ. The purpose of the present study was to determine if striatal mitochondria were differentially affected in two different DSM-IV subgroups of SZ. Postmortem striatal tissue was examined from normal controls (NC), chronic paranoid SZs (SZP), and chronic undifferentiated SZs (SZU). Tissue was processed for calbindin immunohistochemistry to identify striosomal compartments, prepared for electron microscopy and analyzed using stereological methods. In both caudate and putamen, the density of mitochondria in the neuropil was decreased in SZP compared to both NCs and SZU. In the putamen, both the SZP and the SZU subgroups had fewer mitochondria per synapse than did NCs. When examining patch matrix compartments, striatal compartments associated with different circuitry and function, only the matrix exhibited changes. In the caudate matrix, the SZP subgroup had fewer mitochondria in the neuropil than did the SZU and NCs. In the putamen matrix, the SZP had fewer mitochondria in the neuropil as compared to NCs, but not the SZU. The numbers of mitochondria per synapse in both the SZP and the SZU groups were similar to each other and fewer than that of NCs. A decrease in mitochondrial density in the neuropil distinguishes the SZP from the SZU subgroup, which could be associated with the symptoms of paranoia and/or could represent a protective mechanism against some of the symptoms that are less pronounced in this subtype than in the SZU subgroup such as cognitive and emotional deficits.