Lack of association between clinical symptoms and postmortem indices of brain serotonin function in Alzheimer's disease

Oxidative mechanisms and tardive dyskinesia

Tardive dyskinesia has been and continues to be a significant problem associated with long-term antipsychotic use, but its pathophysiology remains unclear. In the last 10 years, preclinical studies of the administration of antipsychotics to animals, as well as clinical studies of oxidative processes in patients given antipsychotic medications, with and without tardive dyskinesia, have continued to support the possibility that neurotoxic free radical production may be an important consequence of antipsychotic treatment, and that such production may relate to the development of dyskinetic phenomena. In line with this hypothesis, evidence has accumulated for the efficacy of antioxidants, primarily vitamin E (alpha-tocopherol), in the treatment and prevention of tardive dyskinesia. Early studies suggested a modest effect of vitamin E treatment on existing tardive dyskinesia, but later studies did not demonstrate a significant effect. Because evidence has continued to accumulate for increased oxidative damage from antipsychotic medications, but less so for the effectiveness of vitamin E, especially in cases of long-standing tardive dyskinesia, alternative antioxidant approaches to the condition may be warranted. These approaches may include the use of antioxidants as a preventive measure for tardive dyskinesia or the use of other antioxidants or neuroprotective drugs, such as melatonin, for established tardive dyskinesia.

Psychosis Due to Neurologic Conditions

Psychosis arises with considerable frequency in a number of neurologic conditions. The treatment of such patients is often challenging, as many of the treatments for psychosis pose some risk of worsening the underlying neurologic condition. Although psychosis may emerge in the context of any neurologic condition that sufficiently disrupts the functioning of or connections between limbic, paralimbic, frontal, subcortical areas mediating complex sensory perception, interpretation, and thought or language organization, secondary psychoses are most often encountered in patients with Alzheimer's disease (Parkinson's disease receives dopaminomimetic therapies) and epilepsy. Psychosis, and particularly delusions and visual hallucinations, may arise in Alzheimer's disease. Based on the available literature, the first-line therapy for this problem is risperidone 0.5 to 3 mg per day. If this treatment proves unsuccessful, low-dose haloperidol or olanzapine should be considered next. If these treatments prove unsuccessful, quetiapine should then be considered. Finally, clozapine may be useful for treatment-refractory psychosis due to Alzheimer's disease, but due caution is warranted given its considerable anticholinergic properties and potential for worsening cognition in these patients. Although disease-emergent psychosis (paranoid delusions and visual hallucinations) may develop in patients with Parkinson's disease, psychosis due to dopaminomimetic therapy is much more common. When such symptoms develop, the accepted first step is to taper anti-parkinsonian medications were possible. Anticholinergic medications, amantadine, selegiline, and dopamine receptor agonists should be reduced or discontinued, provided that the patient can tolerate changes in motor symptoms attendant to such reductions. When these reductions are not feasible or fail to improve treatment-emergent psychosis, low-dose quetiapine or clozapine may be useful. The greatest body of evidence supports the effectiveness of these treatments and their relative lack of adverse effects on motor function. When psychosis develops in the context of epilepsy, the generally accepted first step is to maximize anticonvulsant therapy in an effort to reduce the possible contribution of electrophysiologic disturbances in the described areas to psychotic symptoms. When interictal psychosis persists despite such adjustments, initiation with low-dose atypical antipsychotics carries the least risk of lowering seizure threshold and should be considered.

Pharmacotherapy of behavioral and psychological symptoms of dementia: time for a different paradigm?

Behavioral and psychological symptoms of dementia can occur in 60-80% of patients with Alzheimer's disease or other dementing illnesses, and are important in that they are a source of significant caregiver stress and often precipitate nursing home placement. These symptoms, namely, aggression, delusions, hallucinations, apathy, anxiety, and depression, are clinically managed with a variety of psychotropic drugs such as antipsychotics, antidepressants, antiepileptic drugs, and benzodiazepines. Various advances in the neuropathophysiology and pharmacotherapy must be considered in the optimal design of regimens for patients with these symptoms.