Possible associations among plasma prolactin levels, tardive dyskinesia, and paranoia in treated male schizophrenics

Identifying dopamine supersensitivity through a randomized controlled study of switching to aripiprazole from other antipsychotic agents in patients with schizophrenia

BACKGROUND

Aripiprazole has been reported to worsen psychotic symptoms when switching from other antipsychotics, possibly due to dopamine supersensitivity psychosis.

OBJECTIVE

This study aimed to explore the predictors and possible underlying mechanisms of aripiprazole-related psychotic exacerbation.

METHODS

We conducted an 8-week, open-label, randomized controlled study from October 2007 to September 2009, assigning patients with a primary diagnosis of schizophrenia or schizoaffective disorder to switch from other antipsychotics to aripiprazole with 2-week dual administration, and then to taper off the original agents in fast (n = 38, within 1 week) or slow (n = 41, within 4 weeks) strategies. Positive and Negative Syndrome Scale (PANSS) was examined at day 0, 7, 14, 28, 56. Aripiprazole-related exacerbation (ARE) was defined positive as a 2-point increase in delusion/hallucination dimension score within 28 days compared with baseline. Baseline demographic, clinical and intervention-related variables were compared between the ARE+ and ARE- groups.

RESULTS

Of the 79 randomized patients, 21 fulfilled the criteria of ARE+ , and 46 were classified as ARE-. Fourteen patients in the ARE+ group had worsening psychotic symptoms in the first and second weeks. Compared with the ARE- group, the ARE+ group had a higher baseline chlorpromazine equivalent dose (405.8 ± 225.8 mg vs 268.1 ± 165.4 mg, p = 0.007) and was associated with prescription of first-generation antipsychotics (p = 0.038).

CONCLUSIONS

A higher dose of original antipsychotics and prescription of first-generation antipsychotics may be associated with a higher risk of ARE. The underlying mechanism might be covert dopamine supersensitivity psychosis. These findings may help to identify high-risk patients and guide appropriate treatment strategies.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT00545467.

Prolactin and psychopathology in schizophrenia: a literature review and reappraisal

Secretion of the anterior pituitary hormone prolactin can be significantly increased by antipsychotic drugs, leading to a range of adverse effects in patients with schizophrenia. However, there is evidence from a variety of studies that prolactin may also be related to symptom profile and treatment response in these patients, and recent work has identified variations in prolactin secretion even in drug-free patients. In this paper, a selective review of all relevant studies pertaining to prolactin and schizophrenia, including challenge and provocation studies, is presented. The implications of this work are discussed critically. A tentative model, which synthesizes these findings and argues for a significant role for prolactin in the development of schizophrenia, is outlined.

Prolactin as a biomarker for treatment response and tardive dyskinesia in schizophrenia subjects: old thoughts revisited from a genetic perspective

Previous studies investigated whether prolactin (PRL) serum level was a biomarker of antipsychotic response, schizophrenia symptomatology, and tardive dyskinesia. Most of the findings support that antipsychotic drugs modulate PRL levels but PRL is not a steady indicator. Recent results suggest a genetic effect of PRL and PRL receptor (PRLR) polymorphisms in PRL levels indicating that independently of antipsychotic therapy subjects could have altered PRL levels due to their genetic background.We evaluated whether PRL and PRLR variants were associated with treatment outcome and tardive dyskinesia. We observed no association of PRL/PRLR polymorphism with treatment response (best genotypic results include PRL rs849885 and PRLR rs4703509 permuted p=0.326). Regarding tardive dyskinesia, the major allele of PRL rs37364 was nominally associated with risk for tardive dyskinesia in the European ancestry sub-sample (permuted p=0.183). Although we reported no significant associations, it is definitely worthy of investigation to see if together (genetic variants in the PRL system and PRL serum measures) could be a reliable biomarker for antipsychotic response and TD prevalence. Our results suggest that more studies in this context are required to shed light in the molecular mechanisms underlying antipsychotic response and tardive dyskinesia occurrence.

Clinical implications of antipsychotic-induced hyperprolactinemia in patients with schizophrenia spectrum or bipolar spectrum disorders: recent developments and current perspectives

Hyperprolactinemia is increasingly studied as a frequent and potentially important consequence of antipsychotic medication treatment. Some individuals presenting with hyperprolactinemia remain asymptomatic, but others may exhibit a wide range of clinical symptoms resulting from either the direct effects of prolactin on body tissues (galactorrhea, gynecomastia) or endocrine-related secondary effects (sexual and reproductive dysfunction in the short term, and possibly the risk of tumorigenesis and osteoporosis in the longer term). Short-term side effects may negatively impact medication compliance, and long-term effects have the potential for serious health consequences. Antipsychotic medications have differing propensities to cause prolactin elevation. The first-generation antipsychotics, as well as the second-generation antipsychotic risperidone and its active metabolite paliperidone, have been shown to cause marked and sustained elevations in prolactin levels, whereas others of the second-generation antipsychotics appear to have little or no effect on prolactin levels or may decrease prolactin. A comprehensive overview of antipsychotics and hyperprolactinemia is presented together with a review of emerging evidence about the short- and long-term health risks of hyperprolactinemia.

Prolactin level during 5 years of risperidone treatment in patients with psychotic disorders

OBJECTIVE

To investigate prolactin levels and related side effects in 128 men and 90 women initially treated with risperidone.

METHOD

Patients initially treated with risperidone were followed over 5 years, during which 45% were switched to other antipsychotic drugs.

RESULTS

Initially, prolactin levels were fivefold the norm in women, and threefold in men. Diagnosis did not affect the prolactin level if adjustment for sex, current age, and age at onset of psychosis was applied. Prolactin levels did not correlate significantly neither with any Positive and Negative Symptom Scale item or subscale, nor with side effects. Drugs other than risperidone were not associated with high prolactin levels. For patients on continuous monotherapy risperidone treatment, there was a marked linear reduction of prolactin level over all 5 years.

CONCLUSION

Risperidone induces a higher prolactin elevation than other atypical antipsychotics, but the effect adapts over time. Prolactin was not associated with expected side effects (e.g. sexual, mental, or weight gain).

Tardive dyskinesia in schizophrenia is associated with prolactin-related sexual disturbances

Tardive dyskinesia (TD) may occur in never-medicated patients with psychotic illness, indicating the existence of non-medication, possibly disease-related, causes. We tested the hypothesis that, independent of the antipsychotic-induced rise in prolactin, the incidence of TD would be associated with the incidence of prolactin-related sexual disturbances (PRSD), which would be suggestive of a common pathology involving multiple dopamine tracts. Simple, global measures of TD and PRSD (loss of libido, amenorrhea, gynaecomastia, impotence, and galactorrhea) were rated in a prospective, observational European Health Outcomes Study (SOHO). New onset of TD and new onset of PRSD at 3, 6, and 12 months was analyzed in a risk set of 4263 patients using a Cox proportional hazard model yielding adjusted hazard ratios (aHR). Incidence of TD was significantly and linearly comorbid with the incidence of PRSD in both men and women. Compared to those with no PRSD, the risk for TD was 2.0 (95% CI: 1.1, 3.7) with one PRSD, 2.4 (95% CI: 1.3, 4.5) with two PRSD, and 3.6 (95% CI: 1.1, 11.8) with three PRSD. Associations were stronger in those who only had received prolactin-sparing medications (aHR per unit PRSD increase=2.0, 95% CI: 1.2, 3.3) than in those who only had received prolactin-raising medications (aHR=1.3, 95% CI: 0.9, 1.9). In people with schizophrenia, TD and PRSD show comorbidities that are independent of antipsychotic-induced alterations in plasma prolactin. This may suggest a shared, pandopaminergic pathological mechanism associated with schizophrenia itself, rather than only a medication effect.

Serum prolactin levels in unmedicated first-episode and recurrent schizophrenia patients: a possible marker for the disease's subtypes

Various studies indicate that we must consider schizophrenia not as a single disease but as several distinct etiological processes that give rise to characteristic symptoms. In the current study, we aimed to examine prolactin serum levels in unmedicated first-episode and recurrent schizophrenic patients. The prolactin levels were compared among the different schizophrenia subtypes, i.e. paranoid, schizoaffective and disorganized. Prolactin serum samples were assessed on the morning after the admission in 48 first-episode and 38 recurrent unmedicated hospitalized schizophrenia patients. Two psychiatrists made the diagnosis without knowledge of laboratory results and completed the rating scales. Despite all prolactin levels being within or close to the normal range, we found significant differences in prolactin serum levels among schizophrenia subtype patients: the lowest values were for the paranoid type, intermediate for the schizoaffective and the highest for the disorganized patients. The results seem to indicate a pronounced hyperdopaminergic activity in paranoid schizophrenia, suggesting differences in dopaminergic tone between the schizophrenia subtypes, and support the clinical and the neuropsychological individuality of disease subtypes. There were no significant differences in prolactin serum levels of the schizophrenia subtypes between the first-episode and the recurrent patients. It appears that there are constant patterns of dopamine bioactivity in acutely psychotic unmedicated schizophrenia patients, whether the patients are first admitted or recurrent.

Plasma prolactin and homovanillic acid as markers for psychopathology and abnormal movements during maintenance haloperidol treatment in male patients with schizophrenia

Measurement of plasma prolactin (PRL) concentration and plasma homovanillic acid (HVA) concentration was performed in 24 patients with schizophrenia during maintenance haloperidol treatment. A significant inverse correlation was found between plasma PRL and ratings of both dyskinesia and thought disorder. Plasma PRL was also correlated with negative symptoms. No relationship was found between plasma HVA and any symptom grouping. Twelve patients received an apomorphine challenge; a trend toward a significant inverse relationship was found between baseline dyskinesia and apomorphine-induced decreases in plasma PRL. Plasma PRL and plasma HVA may reflect different elements of dopamine function in the central nervous system during maintenance treatment; plasma PRL may be the useful marker under these conditions.

Prolactin response to submaximal stimulation by TRH in nonaffective psychoses

Nonaffective psychotic symptoms are heterogeneous and probably caused by mixed biopathology. A preliminary investigative tool to study pituitary dopamine activity, the prolactin response to submaximal stimulation by thyrotropin-releasing hormone (TRH) (mini-TRH test) was correlated in 20 subjects with nonaffective psychoses to positive psychotic symptoms as assessed by the Comprehensive Psychiatric Rating Scale psychosis subscale. A significant positive correlation was observed between the response and ratings of nonparanoid symptoms, especially nonparanoid delusions and disrupted thoughts. Because, in addition to pituitary dopamine activity, there is evidence to suggest that the response reflects extrapituitary dopamine activity as well, the results extend the evidence that nonparanoid acute productive psychotic symptoms may be associated with hypoactivity rather than with hyperactivity of brain dopaminergic systems.

Enhanced haloperidol-induced prolactin stimulation with chronic neuroleptic treatment in the rat

Animals were treated either acutely, or chronically for 21 days, with a low dose (0.1 mg/kg) of haloperidol, then sacrificed to obtain trunk blood for radioimmunoassay of prolactin (PRL) level. PRL concentrations on day 21 of chronic treatment were greater than two-fold those produced by acute neuroleptic. Challenge with apomorphine to rats withdrawn for 48 hours revealed similar PRL reductions as a group withdrawn from chronic vehicle injections.

Prolactin shifts after neuroleptic withdrawal

Neuroleptic-induced alterations in serum prolactin levels may have important clinical implications. Twenty-two stable schizophrenic patients, taken off medication over a 3-week period, were followed for 40 weeks or until the neuroleptic was reinstituted. Serum prolactin levels were measured during neuroleptic treatment and during the neuroleptic-free period. When serum prolactin levels were plotted over time, 55% of the subjects showed shifting prolactin levels in the shape of a "V" (i.e., a fall in prolactin level preceding an increase in the level) in the early weeks following withdrawal. Subjects with the "V" shape had significantly lower prolactin levels during neuroleptic treatment than those without the "V" shape. The pathophysiological significance of the prolactin "V" pattern is uncertain. It is consistent, however, with transient dopaminergic hyperactivity following neuroleptic withdrawal.

Neuroendocrinology and limbic epilepsy: relationships to psychopathology, seizure variables, and neuropsychological function

Correlations were sought among neuroendocrine, psychopathologic, neuropsychological, and seizure variables in 16 male patients with limbic epilepsy. Plasma prolactin and luteinizing hormone levels were directly correlated with seizure frequency. Plasma prolactin was inversely correlated with thought disorder. Post hoc findings included a strong direct correlation between total plasma testosterone levels and aggression. These relationships may help to elucidate mechanisms related to interictal symptomatology in patients with limbic epilepsy.

Effect of neuroleptic withdrawal on plasma prolactin: a possible marker of receptor adaptation

Stable schizophrenic and schizoaffective outpatients underwent abrupt withdrawal from a fixed dose of neuroleptic. Prolactin concentrations were determined preceding and following drug withdrawal. Basal prolactin concentrations were significantly lower 3, 4, or 5 days following drug withdrawal than on subsequent days. This rebound effect may be related to dopaminergic receptor changes in the tuberoinfundibular system that are induced by chronic neuroleptic administration.

Acute psychosis in a woman with a prolactinoma

Changes in dopaminergic activity were inferred in a woman with a known prolactinoma several months prior to an acute psychotic episode. Serum prolactin levels reflected central dopaminergic activity, since both the endocrinologic regulation of prolactinomas and the pathophysiology of acute psychosis have been linked to alterations in dopaminergic activity. Serum prolactin levels fell approximately four months prior to onset of the psychotic episode and thus may have provided a predictive indicator of changing dopamine activity in both the tubero-infundibular and the mesolimbic-mesocortical dopaminergic systems.