Rationale and neurobiological effects of treatment with antipsychotics in patients with chronic schizophrenia considering dopamine supersensitivity

Management of schizophrenia and comorbid substance use disorders: expert review and guidance

BACKGROUND

Schizophrenia and substance use disorders (SUDs) are often comorbid conditions that present clinical challenges due to their heterogeneity and the difficulties associated with poor physical health, low medication adherence, high relapse and hospitalization rates, and increased risk of mortality. This is often exacerbated by a fragmented health care system that treats addiction and mental illness separately, leading to delays in proper diagnosis and treatment.

MAIN TEXT

The aim of this narrative review, based on an extensive literature search and experts' clinical experience, is to synthesize evidence on the psychopathological and clinical characteristics of patients, the burden and management at the level of healthcare system, and possible gaps in the treatment of schizophrenia with comorbid SUD in order to understand and address the needs of patients. Treatment options, differences between antipsychotic medications, and the benefits of long-acting formulations and partial dopaminergic agonists are described. Partial dopamine agonists (aripiprazole, cariprazine, and brexpiprazole) have demonstrated good control of psychotic symptoms and SUDs with a favorable safety profile.

CONCLUSION

Pharmacological interventions should be accompanied by psychosocial support within an integrated and multidisciplinary approach that promotes shared decision-making and a good therapeutic alliance between the entire medical team and the patient.

Can brexpiprazole be switched safely in patients with schizophrenia and dopamine supersensitivity psychosis? A retrospective analysis in a real-world clinical practice

BACKGROUND

Several studies have reported that a switch to the dopamine partial agonist (DPA) aripiprazole (ARP), especially when the switch is abrupt, is likely to fail and sometimes worsen psychosis in schizophrenia patients already under high-dose antipsychotic treatment. Such a switching failure is speculated to be related to be the dopamine supersensitivity state. The risks of switching to the DPA brexpiprazole (BREX) have not been reported.

AIMS AND METHODS

We retrospectively analyzed the cases of 106 patients with schizophrenia to identify any factors related to the success or failure of switching to BREX.

RESULTS

The comparison between the patients with dopamine supersensitivity psychosis (n = 44) and those without (n = 62) revealed no significant difference in the switching failure judged at the sixth week. A comparison of the patients with successful switching (n = 80) and those who failed (n = 26) revealed that patients with treatment-resistant schizophrenia (TRS) were significantly more likely to fail. A logistic regression analysis also revealed that patients with past failure of switching to ARP are likely to succeed in switching to BREX. The 2-year follow-up of the patients with successful switching to BREX suggested that the patients who were treated with BREX, even temporarily, experienced some improvement in their Global Assessment of Functioning and Clinical Global Impression-Severity scores.

CONCLUSIONS

Overall, the results indicate that patients with schizophrenia can be switched more safely to BREX compared to ARP. However, the failure of switching to BREX could be higher in patients with TRS, and thus, starting BREX treatment in refractory patients warrants careful monitoring.

The temporal dynamics of transition to psychosis in individuals at clinical high-risk (CHR-P) shows negative prognostic effects of baseline antipsychotic exposure: a meta-analysis

Meta-analytic evidence indicates that baseline exposure to antipsychotics (AP) in individuals at clinical high-risk for psychosis (CHR-P) is associated with an even higher risk of transition to psychosis. However, the temporal dynamics of such prognostic effect have not been clarified yet. This study was therefore designed to address this knowledge gap. We performed a systematic review and meta-analysis of all longitudinal studies published up to 31 December 2021 on CHR-P individuals identified according to a validated diagnostic procedure and reporting numeric data of transition to psychosis according to baseline antipsychotic exposure. 28 studies covering a total of 2405 CHR-P were included. 554 (23.0%) were exposed to AP at baseline, whereas 1851 (77.0%) were not. At follow-up (12 to 72 months), 182 individuals among AP-exposed (32.9%; 95% CI: 29.4% to 37.8%) and 382 among AP-naive CHR-P (20.6%; 18.8% to 22.8%) developed psychosis. Transition rates increased over time, with the best-fit for an ascending curve peaking at 24 months and reaching then a plateau, with a further increase at 48 months. Baseline AP-exposed CHR-P had higher transition risk at 12 months and then again at 36 and 48 months, with an overall higher risk of transition (fixed-effect model: risk ratio = 1.56 [95% CI: 1.32-1.85]; z = 5.32; p < 0.0001; Random-effect model: risk ratio = 1.56 [95% CI: 1.07-2.26]; z = 2.54; p = 0.0196). In conclusion, the temporal dynamics of transition to psychosis differ in AP-exposed vs. AP-naive CHR-P. Baseline AP exposure in CHR-P is associated with a persistently higher risk of transition at follow up, supporting the rationale for more stringent clinical monitoring in AP-exposed CHR-P. The insufficiency of more granular information in available primary literature (e.g., temporal and quantitative details of AP exposure as well as psychopathological dimensions in CHR-P) did not allow the testing of causal hypotheses on this negative prognostic association.

Efficacy of Asenapine in Drug-resistant Psychotic Patients with Dopamine Supersensitivity Psychosis: Two Cases

Dopamine supersensitivity psychosis (DSP) is an unstable clinical condition observed in individuals with schizophrenia who have been treated with an antipsychotic medication at a high dosage and/or for a long period. An up-regulation of dopamine D2 receptors (DRD2) is thought to be involved in the essential pathology of DSP. An antipsychotic agent with both tight binding to DRD2 and a long half-life is generally effective for treating DSP, but a patient who meets the criteria of treatment-resistant schizophrenia sometimes needs treatment with clozapine. We report the case details of two patients whose DSP was not controlled with several antipsychotics but was successfully controlled with asenapine. Asenapine binds to a broad range of dopamine receptors and serotonin receptors, and it is thus distinct from other atypical antipsychotics. The unique profile of asenapine may contribute to the control of severe DSP symptoms in individuals with schizophrenia.

Successful switching from risperidone to cariprazine in a schizophrenic patient with pronounced functional deficit. Case report

A 22-year-old male was admitted to an in-patient psychiatric unit for treatment, after a period of 2 years of increasing psychotic symptoms corresponding to a very severe case of schizophrenia across the entire scale of symptom disorder domains along with some drug abuse comorbidity. Previous treatments with olanzapine (OLA) and risperidone (RIS) had been at best partly successful toward his positive symptoms with no, or even worsening effects on the negative symptomatology. Given the gravity of the latter symptoms and functional impairment of our patient, he might thus have been a candidate for clozapine (CLZ) treatment. It was however decided to switch his antipsychotic treatment to cariprazine (CAR), an agent with a novel pharmacological and clinical profile, because of its favorable pharmacodynamic, pharmacokinetic, and tolerability/safety properties. In a follow-up on the patient 6 months after discharge he is not fully recovered, but the recovery attained reflects a marked functional improvement compared to before the RIS-to-CAR switch. The remarkable response to CAR observed may, speculatively, be in line with the suggestion that CAR could offer an alternative, safer, and more tolerable monotherapy approach (vs. CLZ) for patients with severe negative symptoms and functional deficiency resistant to standard antipsychotic treatment. He appears to occasionally still be taking drugs, but no worsening of positive symptoms has been noted. Whether or not he could reach full recovery if he would abstain entirely from drugs of abuse remains an open question.

Repeated eticlopride administration increases dopamine D2 receptor expression and restores behavioral flexibility disrupted by methamphetamine exposure to male rats

Repeated methamphetamine exposure impairs reversal learning in laboratory animals and downregulates dopamine D₂ receptor expression. In the present study, we tested the possibility that repeated exposure to the dopamine D₂ antagonist, eticlopride, would increase D₂ receptor expression, improve behavioral flexibility and restore behavioral flexibility that was disrupted by exposure to methamphetamine in rats. Male Sprague-Dawley rats received repeated daily pretreatment with the dopamine D₂ antagonist, eticlopride (0.0 or 0.3 mg/kg/day, 14 days). Three days after the last treatment, whole brain (minus olfactory bulbs and cerebellum) dopamine D₂ receptor expression was measured using flow cytometry in one group and reversal learning performance was measured in another group. Reversal learning was also measured in other groups prior to and after methamphetamine exposure (0.0 or 2.0 mg/kg, 4 injections, 2 h apart, 1 day) followed by repeated eticlopride (0.0 or 0.3 mg/kg, 14 days) treatment. Eticlopride treatment increased D₂ receptor expression and improved reversal learning performance. Methamphetamine impaired reversal learning performance and eticlopride treatment reversed the deficit. These results suggest that repeated administration of eticlopride can restore behavioral flexibility and that upregulation of D₂ receptors might be an effective adjunct to treatment of methamphetamine misuse.

Combination therapy of modified electroconvulsive therapy and long-acting injectable aripiprazole for dopamine supersensitivity psychosis: a case report

In the treatment of schizophrenia, long-term pharmacotherapy with D2-receptor antagonists can induce dopamine supersensitivity psychosis (DSP). We report a male patient with schizophrenia with suspected DSP due to excessive polypharmacy. He was hospitalized for several years. Most psychotropic drugs were reduced and subsequently stopped without the exacerbation of symptoms by administering modified electroconvulsive therapy (mECT). Aripiprazole was then selected as the main drug for treatment, which was subsequently changed to the long-acting injection formulation. He was eventually discharged and returned home. Combination therapy with mECT and aripiprazole, especially the long-acting injectable formulation, may help improve and prevent DSP.

Optimal Doses of Specific Antipsychotics for Relapse Prevention in a Nationwide Cohort of Patients with Schizophrenia

BACKGROUND AND HYPOTHESIS

Optimal doses of most antipsychotics in the maintenance treatment of schizophrenia are unknown. We aimed to study the risk of severe relapse indicated by rehospitalization for different dose categories of 15 most frequently used antipsychotics in monotherapy in Finland.

STUDY METHODS

We studied the risk of rehospitalization (Adjusted Hazard Ratio, aHR) associated with six antipsychotic monotherapy dose categories (as time-varying dose, measured in defined daily dose, DDDs/day) in a nationwide cohort of persons diagnosed with schizophrenia (n = 61 889), using within-individual analyses to eliminate selection bias.

STUDY RESULTS

Among the 15 most widely used antipsychotics, 13 had a U- or J-shaped dose-response curve, showing the lowest risks of relapse for doses of 0.6-<1.1 DDDs/day vs nonuse of antipsychotics. The exceptions were oral perphenazine (aHR = 0.72, 95% CI = 0.68-0.76, <0.6 DDDs/day), and olanzapine-long-acting injectable (LAI), which had the lowest aHR of any antipsychotic (aHR = 0.17, 95% CI = 0.11-0.25, 1.4-<1.6 DDDs/day). Certain risperidone and perphenazine doses <0.9 DDD/day were associated with 21%-45% lower risk of rehospitalization (P < .001) than the standard dose of 0.9-1.1 DDD/day (ie, 5 mg for risperidone and 30 mg for perphenazine).

CONCLUSIONS

For most antipsychotics, the risk of severe relapse was the lowest during use of standard dose. Our results suggest that olanzapine LAI is highly effective in dose ranges >0.9 DDD/day, and especially at 1.4-<1.6 DDDs/day (405 mg/4 weeks) associated with substantially lower risk of rehospitalization than any dose of any other antipsychotic. The current WHO standard dose definitions appear to be clearly too high for perphenazine and somewhat too high for risperidone.

Childhood traumatic events and the dopaminergic theory of psychosis: A mini-review of studies investigating gene – environment interactions

There is great body of evidence showing a relationship between childhood adversity and psychosis onset. Genetic factors moderate the association between childhood adversity and psychosis risk potentially by influencing biological and/or psychological reaction following exposure to adversity. In this review, we discuss studies identifying the specific genetic variants known to affect dopamine levels involved in this interaction. Our review shows that the catechol-O-methyltransferase (COMT), dopamine D2 receptor (DRD2), AKT1 gene play a key role in mediating the relationship between childhood adversity and development of psychosis. We have also found conflicting findings on the impact of dopamine genes on the relationship between childhood adversity and development of psychosis, suggesting that other genetic and environmental factors should be taken into account. We here discuss the implications of our findings and future directions.