Psychomotor impairment and cognitive disturbances induced by neuroleptics

Abstract

Acra Psj~chintr Sraiid I YY? ' 89 lciippl 380): 53-58 Priiil~d in Br(yiuin -rill ri,qlif.r resevied Psychomotor impairment and cognitive disturbances induced by neuroleptics King DJ. Psychomotor impairment and cognitive disturbances induced by neuroleptics. Acta Psychiatr Scand 1994: 89 (suppl 380): 53-58. 0 Munksgaard 1994.Reviews of the literature have failed to demonstrate any consistent effects of typical or atypical neuroleptics on psychomotor or cognitive function in schizophrenic patients. Better methods and study designs are required, and healthy volunteer studies are necessary to control for variables due to schizophrenic psychopathology. Eye movements are a sensitive, reliable and relatively pure measure of attention and arousal. Two volunteer studies of the effects of single doses of haloperidol (2, 4 and 6 mg), chlorpromazine ( 5 0 mg) and remoxipride (100 and 150 mg) on saccadic and smooth pursuit eye movements are described. All drugs impaired both eye movement measures, but the doses used were not clinically equivalent. No available test is yet able to distinguish between benzodiazepines and neuroleptics.

Smooth pursuit and saccadic abnormalities in first-episode schizophrenia

“…However, much of this research has been carried out on medicated patients, and there are a number of reasons why antipsychotic medication might be expected to effect smooth pursuit performance. First, the abnormality witnessed in schizophrenic patients can be mimicked by the administration of antipsychotics to normal volunteers (King, 1994 ;Malaspina et al 1994), although earlier studies have failed to show this (Holzman et al 1975). Secondly, reduced gain has been observed in the early stages of Parkinson's disease (Waterston et al 1996), in which there is a dopamine deficiency in both the basal ganglia and cortex, and it is well known that neuroleptic medication can cause parkinsonian symptoms in schizophrenics by blockade of dopamine receptors.…”

“…It is, therefore, possible that such oculomotor abnormalities may reflect either neurodegenerative brain changes due to chronicity of illness, since oculomotor abnormalities are witnessed in Alzheimer's disease (Fletcher & Sharpe, 1988) and even healthy aged subjects (Moschner & Baloh, 1994), or the effect of medication-related chronic dopaminergic blockade as patients with Parkinson's disease also have deficits in smooth pursuit and saccadic eye movements (Crawford et al 1989 ;Waterston et al 1996). Indeed, some recent evidence, with healthy volunteers, suggests that smooth pursuit performance may be adversely influenced by antipsychotic medications (King, 1994 ;Malaspina et al 1994). …”

Effects of Haloperidol on Selective Attention A Combined Whole-Head MEG and High-Resolution EEG Study

“…Drugs were orally given to 12 right-handed healthy volunteers (aged 20-28 years; six females) after informed written consent and institutional approval were obtained. Dosage was chosen in accordance with studies showing that 2 mg of haloperidol affects cognitive performance without causing akathisia in healthy subjects (King 1994). The drugs were administered before 3 h, because electrophysiological and positron emission tomagraphy (PET) data have shown that the effects peaked within 2 to 6 hours after haloperidol administration in normal subjects (Bartlett et al 1994;Leigh et al 1992;McClelland et al 1990).…”

Short-Term Cognitive Improvement in Schizophrenics Treated with Typical and Atypical Neuroleptics

“…Considering such short-term effects, it may be helpful to focus on the neuropsychological effects of neuroleptic drugs in healthy volunteers. While King and Henry [17] could not find any effects of 1 mg of haloperidol on cognitive and psychomotor function, haloperidol (2, 4 and 6 mg), chlorpromazine (50 mg) and remoxipride (100 and 150 mg) have been shown to impair saccadic and smooth pursuit eye movements as a measure of attention and arousal in another study [18]. Rammsayer and Gallhofer [19] demonstrated that an acute dose of 3 mg of haloperidol caused a more severe alteration in cognitive functioning, cortical arousal and psychomotor performance than a clinically equipotent dose of 150 mg of remoxipride.…”