Treatment-resistant depression is an important clinical problem presenting a major challenge to clinical psychiatry. While several strategies have been attempted, including medication switch, antidepressant polypharmacy and various augmentative regimens, success remains limited. Amantadine (AMN), an agent traditionally used in the treatment and prophylaxis of influenza, is now known to exhibit prominent effects at the level of dopaminergic, monoamine oxidase and N-methyl-D-aspartate systems. The present reports on the efficacy of AMN as augmentation to standard antidepressant treatment in patients with treatment-resistant depression. Eight patients with treatment-resistant depression consented to receive AMN, titrated up to a dose of 300 mg, over a period of 4 weeks in a non-blinded fashion. Improvement in both depression and anxiety scores were observed from week 1, with patients exhibiting improvement of depressive scores of up to 49% by study completion. Females appeared to exhibit a stronger response, and within a shorter period of time. Side-effects reported included dry mouth and sedation. AMN appears to demonstrate efficacy as a safe and effective augmentative agent in treatment-resistant depression. Further studies are clearly mandated to test these preliminary observations in a double-blinded manner.

The findings of this double-blind, placebo-controlled, crossover study indicate the efficacy of Trz in the management of NIA, corroborating the results of a preliminary pilot study. We suggest that Trz's property of serotonin 2A postsynaptic receptor antagonism may be its principal mechanism for the improvement of NIA.

Comorbid schizophrenia and dementia is a common clinical phenomenon; however, management of the coexisting illnesses remains incomplete. Donepezil, a cholinesterase inhibitor, may be beneficial for the management of symptoms of Alzheimer's disease, a disease in which cholinergic pathways in the cerebral cortex and basal forebrain are well known to be compromised. Furthermore, impaired cognition in elderly schizophrenic patients has been observed to be more than two thirds; however, there are no published controlled studies reporting the use of cholinesterase inhibitors in the management of schizophrenia in patients with associated dementia. In this study, six patients with chronic schizophrenia and comorbid dementia were administered donepezil, 5 mg, in single-blind fashion as augmentation to their standard antipsychotic medication for a 4-week period. Patients were evaluated with the Mini Mental State Examination (MMSE); Alzheimer's Disease Assessment Scale, Cognitive subscale; Positive and Negative Symptom Scale (PANSS); and the Clinical Global Impression (CGI) scales. A significant improvement was noted in MMSE scores (P < 0.01) and for CGI scores (P < 0.01). In addition, three patients demonstrated improvement on the PANSS. Donepezil appears to be an effective treatment for the management of symptoms of dementia accompanying patients with comorbid schizophrenia and dementia. Since cholinergic dysfunction may be present in some patients with schizophrenia, the authors' findings further demonstrate the possibility that this disorder may be managed with cholinergic medications as augmenting agents, at least in this specific subpopulation of patients with comorbid dementia. To confirm the findings of this preliminary trial, further investigation is mandated with a larger sample of subjects in the context of a double-blind medication trial.

Electroconvulsive therapy (ECT) is an effective strategy in some treatment-resistant patients with schizophrenia. However, ECT is associated with cognitive adverse effects, most notably, memory loss. This study examined the effects of rivastigmine, a selective central nervous system acetylcholinesterase inhibitor, with benefits on cognition in Alzheimer disease, on memory performance in patients with schizophrenia treated with ECT. Thirty inpatients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision schizophrenia treated with ECT were coadministered rivastigmine (3-4.5 mg/d) or placebo in a prospective, randomized, double-blind, placebo-controlled trial (maximum period of 4 weeks). Over the ECT course, scores on the cognitive subscale of the Alzheimer's Disease Assessment in subjects receiving placebo showed no significant change, whereas subjects receiving rivastigmine displayed decreased cognitive subscale of the Alzheimer's Disease Assessment scores, indicating cognitive improvement (P < 0.05). Findings suggest possible involvement of the acetylcholinergic system in mediation of cognitive deficits after ECT and indicate possible beneficial effects of rivastigmine coadministration in minimizing some of these ECT-induced cognitive impairments.

Increasing evidence suggests that the cholinergic system is involved in the pathogenesis of schizophrenia. Donepezil, a central cholinesterase inhibitor, improves psychotic symptomatology in demented patients, however, evidence for its role in the management of active psychosis in schizophrenia remains limited. An 18-week double blind cross-over study was conducted in which eight patients were randomly assigned to either donepezil (5 mg/day for the first 4 weeks and 10 mg/day for the following 4 weeks) or placebo as augmentation treatment to clozapine. After this initial phase, there was a 2-week washout period of the study medication after which the same regimen was crossed over at the same dose and for the same period (8 weeks). No significant difference was noted in the total positive and negative symptom scale scores when donepezil was compared with placebo (16.7%+12.97% vs 3.20%+13.94% respectively, p = 0.18). However, three patients improved (>15%) in the total PANSS scores (37.03%, 16.6% and 25.33%) during the donepezil treatment phase, while only one patient improved (20.87%) during the placebo phase. No differences were noted in the Calgary depression scale (p = 0.305), Simpson Angus scale (p = 0.374), clinical global impression-improvement scale (p = 0.23) and clinical global impression-severity of illness scores (p = 0.116). Although this preliminary study failed to demonstrate a clear effect of donepezil augmentation in clozapine treated chronic schizophrenia patients, it seems that the subtle positive effect of donepezil observed in some of our patients should encourage further investigation in a larger sample of this patient subpopulation.