Adjuvant therapeutic effects of galantamine on apathy in a schizophrenia patient

Treating disorders across the lifespan by modulating cholinergic signaling with galantamine

Advances in understanding the regulatory functions of the nervous system have revealed neural cholinergic signaling as a key regulator of cytokine responses and inflammation. Cholinergic drugs, including the centrally acting acetylcholinesterase inhibitor, galantamine, which are in clinical use for the treatment of Alzheimer's disease and other neurodegenerative and neuropsychiatric disorders, have been rediscovered as anti-inflammatory agents. Here, we provide a timely update on this active research and clinical developments. We summarize the involvement of cholinergic mechanisms and inflammation in the pathobiology of Alzheimer's disease, Parkinson's disease, and schizophrenia, and the effectiveness of galantamine treatment. We also highlight recent findings demonstrating the effects of galantamine in preclinical and clinical settings of numerous conditions and diseases across the lifespan that are characterized by immunological, neurological, and metabolic dysfunction.

The effects of galantamine on psychopathology in chronic stable schizophrenia

OBJECTIVES

Galantamine is an acetylcholinesterase inhibitor and an allosteric modulator of the alpha4beta2 and alpha7 nicotinic receptors. There are several case reports describing the potential benefits of galantamine for negative symptoms associated with schizophrenia. This secondary analysis describes the effects of galantamine on psychopathology in people with schizophrenia.

METHODS

Subjects with clinically stable chronic schizophrenia were randomized to adjunctive galantamine (24 mg/d) or placebo in a 12-week double-blind trial. Symptomatology was assessed with the Brief Psychiatric Rating Scale (BPRS) and the Clinical Global Impression Scale. The Scale for the Assessment of Negative Symptoms (SANS) was used to measure negative symptoms.

RESULTS

Eighty-six patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of schizophrenia or schizoaffective disorder taking a stable dose of antipsychotic medications were randomized to adjunctive treatment with study drug (galantamine, n = 42; placebo, n = 44); 73 subjects completed the study (galantamine, n = 35; placebo, n = 38). No significant differences were found on BPRS total score (P = 0.585) or BPRS subfactor scores. Scale for the Assessment of Negative Symptoms total scores also did not decrease significantly (P = 0.106) in either group; however, galantamine treatment was associated with a greater benefit in the SANS subfactor, alogia (P = 0.007).

CONCLUSIONS

The lack of robust significant effects of galantamine on negative, and other symptom domains, may be due to the relatively low baseline level of these symptoms in the tested population. Galantamine may have some benefit on certain negative symptoms, particularly alogia. Studies specifically designed to address the issue of the efficacy of galantamine for negative symptoms are needed to confirm this observation.

Electroencephalographic effects of galantamine in major depressive disorder

Nicotinic acetylcholine receptor stimulation is a potential target for controlling symptoms in several psychiatric disorders. Galantamine is a cholinesterase inhibitor that can modulate the nicotinic receptor sites. In this study, we examined the effect of galantamine on the quantitative EEG in patients with major depression. Twenty patients were included in a randomized, double-blinded, placebo-controlled trial. Patients received galantamine (8 mg/day for 4 weeks then 16 mg/day for another 4 weeks) or placebo for eight weeks. Quantitative EEG using the international 10 to 20 configuration, 9 minutes of resting, eyes closed, and eyes open was done before and after the study period. Nineteen patients completed the study and their data were included in the final analysis. The results showed that galantamine compared with placebo reduced absolute band power that was statistically significant (using multivariate analysis of variance) for beta wave [F(1,17) = 2.48, P = 0.03]; the between-subject effect was significant on the left and right posterior, and left central regions. The multivariate analysis of variance model for alpha was not significant [F(1,17) = 1.07, P = 0.43]. We suggest that the reduction in absolute power after galantamine administration could be a sign of brain activation as a result of modulation of neurotransmitter release. We recommend the initiation of a larger study to confirm our findings and help in understanding the neuropathology of major depression.

[Cholinergic hypothesis in psychosis following traumatic brain injury and cholinergic hypothesis in schizophrenia: a link?]

INTRODUCTION

While traumatic brain injury is a major public health issue, schizophrenia-like psychosis following traumatic brain injury is relatively rare and poorly studied. Yet the risk of developing schizophrenia-like psychosis after traumatic brain injury is 3 times more important than in the general population.

LITERATURE FINDINGS

Risk factors associated with onset of psychosis after traumatic brain injury include: left hemispheric lesions, closed head injury and coma of duration superior to 24 hours. Most patients develop symptoms of psychosis after a moderate to severe traumatic brain injury and often have lesions of the frontal and temporal lobes. CHOLINERGIC HYPOTHESIS:

ARGUMENTS

Neuropathologic, electrophysiological and pharmacologic evidence show that cognitive impairment including attention, memory and executive functioning impairment may be related with cholinergic dysfunction in patients with traumatic brain injury. The cholinergic hypothesis is also incriminated in the genesis of schizophrenia. The same biochemical disorders found in schizophrenia which imply many neurotransmitters are often present immediately after traumatic brain injury. However in chronic cognitive disorders secondary to traumatic brain injury, the cholinergic system alone seems to be specifically implied. This is due to the fragility of the cholinergic fibres and a chronic yet reversible reduction of the cholinergic reserves after traumatic brain injury. Cholinergic function can be studied by the P50 evoked response to paired auditory stimuli.While this is disturbed in patients presenting with cognitive impairment after traumatic brain injury its normalisation can be obtained after administration of an acetylcholine esterase inhibitor. In schizophrenic patients there is also an abnormal P50 evoked response due in part to a low number of alpha 7 nicotinic receptors which are implicated in sensory filtering in the frontal lobe. Moreover in schizophrenia, post-mortem studies show a negative correlation between the activity of acetylcholine transferase in the parietal cortex and the severity of the cognitive deficits, as well as a lesser density of the muscarinic M1 and M4 receptors in the frontal lobe. The lower concentration of M1 receptors in the frontal cortex is correlated with the severity of the positive symptoms. THERAPEUTICAL PERSPECTIVES: Antipsychotics have emerged as the first line treatment of psychotic disorders. In research, their ability for enhancing cognitive function could result in the increase of acetylcholine in the medial prefrontal cortex. Acetylcholinesterase inhibitors have been widely used for treatment of cognitive impairment in Alzheimer's disease. Galantamine could be interesting in schizophrenia and psychosis following traumatic brain injury because it has a dual mechanism of action: selective competitive inhibition of acetylcholinesterase and allosteric potentialisation of nicotinic receptor response. Therefore Galantamine remains active in nicotine addicted schizophrenic patients who may smoke as an auto treatment. Galantamine has shown efficacy in adjunction to Risperidone in one patient presenting with psychosis following traumatic brain injury and in 3 case reports of schizophrenic patients.

CONCLUSION

Further systematic studies are needed to confirm this hypothesis.

Cognitive deficits in schizophrenia: focus on neuronal nicotinic acetylcholine receptors and smoking

Patients with schizophrenia present with deficits in specific areas of cognition. These are quantifiable by neuropsychological testing and can be clinically observable as negative signs. Concomitantly, they self-administer nicotine in the form of cigarette smoking. Nicotine dependence is more prevalent in this patient population when compared to other psychiatric conditions or to non-mentally ill people. The target for nicotine is the neuronal nicotinic acetylcholine receptor (nAChR). There is ample evidence that these receptors are involved in normal cognitive operations within the brain. This review describes neuronal nAChR structure and function, focusing on both cholinergic agonist-induced nAChR desensitization and nAChR up-regulation. The several mechanisms proposed for the nAChR up-regulation are examined in detail. Desensitization and up-regulation of nAChRs may be relevant to the physiopathology of schizophrenia. The participation of several subtypes of neuronal nAChRs in the cognitive processing of non-mentally ill persons and schizophrenic patients is reviewed. The role of smoking is then examined as a possible cognitive remediator in this psychiatric condition. Finally, pharmacological strategies focused on neuronal nAChRs are discussed as possible therapeutic avenues that may ameliorate the cognitive deficits of schizophrenia.

Add-on therapy with acetylcholinesterase inhibitors for memory dysfunction in schizophrenia: a systematic quantitative review, part 2

RATIONALE

Memory impairment is frequent in schizophrenia and remains difficult to treat. Improved memory function is associated with a better functional outcome. Some clinical trials have used add-on therapy with acetylcholinesterase inhibitors (AChEIs) to test the cognitive enhancement effect of this kind of medication, which is usually prescribed for other indications than schizophrenia.

OBJECTIVE

To perform a systematic review with meta-analysis.

METHODS

Studies were identified using electronic search engines, hand searches, cross-referencing of studies, and contacts with investigators. Eligible studies were those comparing cognitive performance in patients with schizophrenia before and after AChEI treatment, randomized controlled trials, and crossover and open trials of AChEI in people with schizophrenia, with trial duration of more than 2 weeks. Validated neurocognitive measures and computerized batteries were used to corroborate the effect.

RESULTS

Our findings reveal a small to medium improvement in short-term memory and long-term memory (LTM) performance when patients are compared with the baseline performance, but when compared with controls (placebo treatment) at the end of the trial, they performed worse on both short-term memory and on LTM. However, the effects were nonsignificant. The LTM magnitude estimate demonstrating a treatment effect between the start and end points of the trial consisted of 8 studies (before treatment, n = 209; overall attrition rate, 8%). The effect estimate was significant and close to heterogeneous. Duration of trial increases the effect estimate slightly. The analysis was broken down by AChEI: 5 studies of donepezil (effect size [ES], -0.352), 2 studies of rivastigmine (ES, 0.383), and 1 study of galantamine. There were 6 studies of AChEI added to second-generation antipsychotics (ES, 0.424) and 2 studies of first-generation antipsychotics (ES, 0.207).

CONCLUSIONS

Notwithstanding an extensive investigation, eligible data for the meta-analysis were nominal. To date, and overall, our quantitative systematic review provides no clear evidence on whether AChEIs should be prescribed for memory enhancement in patients with schizophrenia.

Synergistic effect of combined treatment with risperidone and galantamine on phencyclidine-induced impairment of latent visuospatial learning and memory: Role of nAChR activation-dependent increase of dopamine D1 receptor-mediated neurotransmission

The clinically achievable efficacy of the atypical antipsychotics on cognitive symptoms of schizophrenia is practically limited by their dose-dependent side effects. Thus, there is the need for adjuvant treatments or strategies for the cognitive impairments. Further, human autopsy and genetic data in schizophrenia have indicated the existence of the abnormality of nicotinic acetylcholine receptors (nAChR). In the present study, we aimed to investigate the synergistic effect and mechanisms of a combined treatment with an atypical antipsychotic risperidone and galantamine, which is a nAChR-allosteric modulator and a modest cholinesterase inhibitor, on the impairment of latent visuospatial learning and memory in mice resembling the cognitive impairment of schizophrenia. Repeated treatment with phencyclidine (PCP, 10 mg/kg, 14 days)-induced cognitive impairment in mice in a one trial water-finding test was used as a model of the cognitive impairment of schizophrenia. In vivo microdialysis was used to investigate the extracellular concentration of dopamine in the medial prefrontal cortex (mPFC). Combined treatment with galantamine and risperidone, at low, ineffective doses (both at 0.05 mg/kg) showed a synergistic effect to reverse cognitive impairment and increase extracellular concentration of dopamine in the mPFC. The synergistic behavioral effect was abolished by a dopamine-D1 receptor antagonist, SCH 23390, and a nAChR antagonist, mecamylamine, but not a muscarinic AChR (mAChR) antagonist, scopolamine. Mecamylamine also blocked the synergistic effect on dopamine release in the mPFC of PCP-treated mice. The study indicates that galantamine and risperidone may have synergistic effect on the cognitive impairments in schizophrenia patients by synergistically promoting the nAChR activation-dependent increase of dopamine D1 receptor-mediated neurotransmission.

Oral cholinesterase inhibitor add-on therapy for cognitive enhancement in schizophrenia: a quantitative systematic review, Part I

RATIONALE

Cognitive impairment in schizophrenia is associated with outcomes affecting social function and vocational performance. Cognitive enhancement is thus recognized as fundamental in the treatment of schizophrenia. Some clinical trials have used acetylcholinesterase inhibitors (AChEIs) add-on therapy to test the cognitive-enhancing effects of these kinds of medication, which is usually prescribed for indications other than schizophrenia.

OBJECTIVE

To perform a quantitative systematic review of the effects of AChEI on various cognitive domains (attention, language, and motor and executive functions) in schizophrenia.

DATA SOURCE

Exhaustive electronic search engines, hand searches, cross-referencing of studies, and contacts with investigators were carried out.

DATA SELECTION

The studies included compared neurocognitive performance in patients with schizophrenia before and after AChEI treatment in randomized controlled trials and crossover and open trials of AChEI in people with schizophrenia.

RESULTS

Our findings reveal a small, but significant, homogeneous effect estimate of AChEI on attention before and after treatment. A small nonsignificant heterogeneous effect estimate was yielded for motor performance after AChEI treatment. However, no significant change appears in language performance or executive functions after AChEI treatment, independently of the type of AChEI. After AChEI treatment, when patients were compared with control groups, no difference appears in attention and executive functions. Nevertheless, the analysis reveals that the control groups performed better on language tasks than patients after AChEI treatment but worse on motor tasks.

CONCLUSIONS

Despite an extensive investigation of the electronic and gray literature, few data appropriate for the meta-analysis were found. The results reveal a small improvement in attention and a trend on motor tasks after AChEI medication in schizophrenia. No clear conclusion can yet be reached concerning the cognitive-enhancing effects of AChEI considering the small number of studies available. This finding needs to be substantiated by larger trials. This systematic review complements a meta-analysis focusing on memory, which showed a small improvement with a cocktail of antipsychotics and AChEIs.

Refractory psychosis and prominent cognitive deficits in a patient with mega-cisterna magna

We present a case of refractory psychosis with prominent cognitive deficits in a patient with 'mega-cisterna magna', a congenital defect within the 'Dandy-Walker Complex' continuum. The 21-year-old female had a 3-year history of refractory psychotic symptoms despite adequate antipsychotic treatment. CT and MRI scans disclosed 'mega-cisterna magna'. Thorough neuropsychological testing recorded extensive deficits. Treatment with amisulpride 1200 mg/day resulted in a 30% decrease in PANSS score within 2 months. Then galantamine 8 mg/day was added and PANSS score decreased further by 27% within 2 weeks. Cognitive and social functioning was overall much improved. The effect was sustained in a 24 months follow-up. It is postulated that even a less extended cerebellar lesion, such as mega-cisterna magna, can be associated with psychosis, and in some cases with treatment refractoriness or cognitive dysfunction. Adjuvant galantamine may improve cognitive and psychosocial functioning in these patients.

Synergistic effect of galantamine with risperidone on impairment of social interaction in phencyclidine-treated mice as a schizophrenic animal model

Social withdrawal is the first sign and key component of the negative symptoms of schizophrenia. The efficacy of risperidone, an atypical antipsychotic, on the symptom is practically limited by dose-dependent side effects in clinical trials, therefore there is the need for adjuvant treatments. In the present study, we aimed to investigate the synergistic effect and mechanism of risperidone and galantamine, which is a nicotinic acetylcholine receptor (nAChR)-allosteric modulator and a modest cholinesterase inhibitor, on phencyclidine (PCP)-treated mouse model of social withdrawal. At non-effective doses by themselves, co-administration of galantamine (0.05mg/kg) and risperidone (0.05mg/kg) showed synergistic effects on PCP-induced impairments of social interaction and dopamine release in the medial prefrontal cortex (mPFC). The behavioral synergistic effect was abolished by the administration of a dopamine-D(1) receptor antagonist, SCH 23390 (0.02mg/kg, systemic; or 0.02microg/0.5microL/mouse, intra-mPFC), and a nAChR antagonist, mecamylamine (3mg/kg), but not a muscarinic receptor antagonist, scopolamine (0.1mg/kg). Mecamylamine (3mg/kg) also abolished the synergistic effect on dopamine release in the mPFC. We conclude that galantamine may have synergistic effect with risperidone on the negative symptom of social withdrawal in schizophrenia, which is mediated by dopamine-D(1) receptors in the mPFC through nAChR activation-increased dopamine release.