Pharmacological treatment of negative symptoms of schizophrenia: therapeutic opportunity or cul-de-sac?

Efficacy of selegiline add on therapy to risperidone in the treatment of the negative symptoms of schizophrenia: a double-blind randomized placebo-controlled study

OBJECTIVE

It has been reported that selegiline, a Selective Monoamine Oxidase Inhibitor B (MAOI-B), at low doses would be helpful for treating negative symptoms in schizophrenia. Nevertheless, the results are contradictory so far. This study was designed to investigate the effect of selegiline added to risperidone as augmentation therapy in patients with chronic schizophrenia and prominent negative symptoms in an 8 week, double blind and randomized clinical trial.

METHODS

Eligible participants in this study were 40 patients with chronic schizophrenia. All patients were inpatients and were in the active phase of the illness, and met DSM-IV-TR criteria for schizophrenia. Patients were allocated in a random fashion, 20 to risperidone 6 mg/day plus selegiline 10 mg/day (5 mg bid) and 20 to risperidone 6 mg/day plus placebo. The principal measure of the outcome was Positive and Negative Syndrome Scale (PANSS).

RESULTS

Although both protocols significantly decreased the score of the positive, negative, and general psychopathological symptoms over the trial period, the combination of risperidone and selegiline showed a significant superiority over risperidone alone in decreasing negative symptoms and PANSS total scores.

CONCLUSION

The present study indicates selegiline as a potential adjunctive treatment strategy for the negative symptoms of schizophrenia. Nevertheless, results of larger controlled trials are needed before recommendation for a broad clinical application can be made.

Negative symptoms in schizophrenia: a review

Negative symptoms refer to the weakening or lack of normal thoughts, emotions or behaviour in schizophrenia patients. Their prevalence in first-episode psychosis is high, 50-90%, and 20-40% of schizophrenia patients have persisting negative symptoms. Severe negative symptoms during the early stages of treatment predict poor prognosis. The aim of the study was to review the current literature on the negative symptoms of schizophrenia. In June 2007, the following databases were searched: Web of Science, PubMed, PsycINFO, Medline (Ovid) and Scopus. The search included articles written in English and no time limit was determined. The studies were manually screened by one of the authors according to the title and abstract. About one in three schizophrenia patients suffer from significant negative symptoms. In these patients, negative symptoms constitute a key element of overall symptoms, weakening their ability to cope with everyday activities, affecting their quality of life and their ability to manage without significant outside help. About one in three schizophrenia patients suffer from significant negative symptoms. Attention should be focused on negative symptoms during the early phase of treatment, because they cause significant impairment to patients' quality of life. So far, no treatment appears to substantially improve negative symptoms narrowly defined. However, according to clinical experience, when treating negative symptoms, the best effect is achieved by optimizing the dose of medication and by complementing it with psychosocial therapies.

Phencyclidine and dizocilpine induced behaviors reduced by N-acetylaspartylglutamate peptidase inhibition via metabotropic glutamate receptors

BACKGROUND

N-methyl-D-aspartate (NMDA) receptor open channel blockers phencyclidine (PCP) and dizocilpine (MK-801) elicit schizophrenia-like symptoms in humans and in animal models. Group II metabotropic glutamate receptor agonists reverse the behavioral effects of PCP and MK-801 in animal models. N-acetylaspartylglutamate (NAAG), the third most prevalent neurotransmitter in the mammalian nervous system, is a selective group II metabotropic glutamate receptor agonist. We previously reported that ZJ43, a potent inhibitor of the enzymes that inactivate synaptically released NAAG, reduced motor and stereotypic effects of PCP in the rat.

METHODS

To confirm the efficacy of NAAG peptidase inhibition in decreasing motor behaviors induced by PCP and MK-801, ZJ43 was tested in additional schizophrenia models.

RESULTS

ZJ43 reduced MK-801-induced motor activation in a mouse model that has been used to characterize the efficacy of a wide range of pharmacotherapies for this human disorder. In a second mouse strain, the peptidase inhibitor reduced PCP-induced stereotypic movements. ZJ43 also reduced PCP-induced negative symptoms in a resident-intruder assay. The group II metabotropic glutamate receptor antagonist, LY341495, blocked the effect of NAAG peptidase inhibition in these mouse models of positive and negative PCP- and MK-801-induced behaviors. Additionally, LY341495 alone increased some PCP-induced behaviors suggesting that normal levels of NAAG act to moderate the effect of PCP via a group II mGluR.

CONCLUSIONS

These data support the proposal that NAAG peptidase inhibition and elevation of synaptic NAAG levels represent a new therapeutic approach to treating the positive and negative symptoms of schizophrenia that are modeled by open channel NMDA receptor antagonists.

The additional therapeutic effect of group music therapy for schizophrenic patients: a randomized study

OBJECTIVE

Schizophrenia is one of the most serious mental disorders. Music therapy has only recently been introduced as a form of treatment. The aim of this study was to examine the effect of music therapy for schizophrenic in-patients needing acute care.

METHOD

Thirty-seven patients with psychotic disorders were randomly assigned to an experimental group and a control group. Both groups received medication and treatment indicated for their disorder. Additionally, the experimental group (n = 21) underwent group music therapy.

RESULTS

Significant effects of music therapy are found in patients' self-evaluation of their psychosocial orientation and for negative symptoms. No differences were found in the quality of life.

CONCLUSION

Musical activity diminishes negative symptoms and improves interpersonal contact. These positive effects of music therapy could increase the patient's abilities to adapt to the social environment in the community after discharge from the hospital.