Alterations in serine racemase indicate that the endogenous NMDA agonist D-serine may be produced abnormally in schizophrenia and that d-serine may be an effective treatment for schizophrenia. Schizophrenia is now treated by medications known as antipsychotics (or neuroleptics) that typically reduce dopaminergic activity because too much activity has been most strongly linked to positive symptoms, specifically persecutory delusions. Dopaminergic drugs do not induce the characteristic auditory hallucinations of schizophrenia. Dopaminergic drug abuse such as abuse of methamphetamine may result in a short lasting psychosis or provocation of a longer psychotic episode that may include symptoms of auditory hallucinations. The typical antipsychotics are known to have significant risks of side effects that can increase over time, and only show clinical effectiveness in reducing positive symptoms. Additionally, although newer atypical antipsychotics can have less affinity for dopamine receptors and still reduce positive symptoms, do not significantly reduce negative symptoms. A 2006 systematic review investigated the efficacy of<unk> rgic drugs as add-on: + Adding<unk> rgic drug to antipsychotics compared to the same antipsychotic plus a placebo for schizophrenia Summary In general, all<unk> rgic drugs appeared to be ineffective in further reducing 'positive symptoms' of the illness when added to the existing antipsychotic treatment. Glycine and D-serine may somewhat improve 'negative symptoms' when added to regular antipsychotic medication, but the results were not fully consistent and data are too few to allow any firm conclusions. Outcome Findings in words Findings in numbers Quality of evidence Global outcome Relapse(add-on glycine) At present it is not possible to be confident about the effect of adding the<unk> rgic drug to standard antipsychotic treatment. Data supporting this finding are very limited. RR 0.39 (0.02 to 8.73) Very low Service outcome Hospital admission(add-on glycine) There is no clarity about the benefits or otherwise of adding a<unk> rgic drug to antipsychotics for outcomes about how much hospital/community care is used. Data supporting this finding are based on low quality evidence. RR 2.63 (0.12 to 59.40) Low Mental state No clinically significant improvement(add-on glycine) There is no evidence of clear advantage of using add-on<unk> rgic to standard antipsychotic medication. These findings are based on data of low quality. RR 0.92 (0.79 to 1.08) Low Adverse effects Constipation(add-on glycine or D-serine) There is no clarity from very limited data. Additional<unk> rgic could cause constipation or help avoid it. Data are very limited. RR 0.61 (0.06 to 6.02) Very low Insomnia(add-on glycine or D-serine) Additional<unk> rgic may help or cause insomnia - it is not clear from the very limited data. RR 0.61 (0.13 to 2.84) Very low Missing outcomes Quality of life This outcome was not reported in any studies
Glutamate hypothesis of schizophrenia
Dopamine hypothesis of schizophrenia
Dopamine supersensitivity psychosis
Basic symptoms of schizophrenia
Ion channel hypothesis of Alzheimer's disease
Epigenetics of schizophrenia
Pseudoneurotic schizophrenia
Simple-type schizophrenia