Biomedical subjects
Publications and source records attributed to M M Singh.
Three patients, aged 23-33 years, with the diagnosis of schizophrenia, developed symptoms of tardive dyskinesia while receiving neuroleptic treatment, mostly with haloperidol. Existential problems and emotional upset seemed contributory. Diazepam was found effective in controlling dyskinesia. Its therapeutic effect seemed not to be related to sedation. Some implications of the reported observations are mentioned.
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Data on the subjective responses to neuroleptic treatment and their prognostic implications are reported from a multidimensional double-blind study of the pharmacotherapeutic process in schizophrenia. From these data it seems that the occurrence of a dysphoric response in the course of neuroleptic treatment is associated with a less favorable therapeutic response and long-term prognosis. It is suggested that the dysphoric responders, many of whom belong to the category of nuclear or poor prognosis schizophrenia, may be fundamentally different from the others.
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In a double-blind, cross-over study, the comparative therapeutic effects of 6-week courses of two prototypic neuroleptics--haloperidol and chlorpromazine--and the reversal of those effects with benztropine were investigated in a group of 18 schizophrenics. Periodic measurements were made for 32 dimensions of psychopathology, social participation, span of attention, sleeplessness, pulse rate and neurological side effects. The results showed that haloperidol was generally a more effective drug over the period studied. This was particularly apparent in terms of social and emotional responsiveness, communicativeness and cognitive processes. The only superiority of chlorpromazine seemed to be that patients felt less dysphoric on it than they did on haloperidol. Haloperidol also proved to be more rapid in its action. The data failed to support the clinical validity of the distinction often made between "sedative" and "activating" neuroleptics. Consistent with previous reports, benztropine had the effect of diminishing therapeutic response to both neuroleptics. However, haloperidol again proved less susceptible to this effect. The slowness and lesser therapeutic efficiency of chlorpromazine and its greater susceptibility to benztropine reversal were all considered to be due to its built-in anti-cholinergic properties acting in opposition to its antipsychotic activity. The low potency of chlorpromazine-like drugs was attributed to their inherent anticholinergic characteristics. It was suggested that one of the factors determining potency difference among neuroleptics may be the degree of built-in anticholinergic activity.
The treatment process with two prototypic neuroleptics--haloperidol and chlorpromazine--and the nontherapeutic effects of trihexyphenidyl on this process were studied in carefully matched groups of ten schizophrenics each, using a "double-blind", repeated-measure, longitudinal research design. Measurements of various aspects of psychopathology, social participation and clinical indices of arousal were made periodically and objective test of cognition and attention were given. The two treatment groups were highly comparable in epidemiological and clinical terms and differed significantly during the baseline period in only one of the 39 parameters. Longitudinal nonparametric analyses showed that significant therepeutic changes tended to occur more quickly and involved a wider spectrum of schizophrenic phenomena with haloperidol than with chlorpromazine. Parametric analyses also indicated that at the completion of the study, haloperidol-treated patients had significant improvement in many more dimensions than the chlorpromazine-treated patients and that the changes with haloperidol were generally of greater magnitude. At the same time, chlorpromazine treatment seemed to be more susceptible to the antagonistic effects of trihexyphenidyl. No differential patterns of responses were noted for the two neuroleptics to provide any clinical validity to the distinction often made between "sedative" and "activating" neuroleptics. These data were in agreement with those from a previous comparative study which had a very different research design and a somewhat different type of schizophrenic population. The clinical and potency differences between the two neuroleptics were again explained on the basis of the fact that chlorpromazine has much stronger built-in anticholinergic properties, which may be acting in opposition to the antipsychotic activity. It was suggested that the degree of inherent anticholinergic activity may be an important determinant of potency differences among presently known neuroleptics. The possible role of cholinergic mechanisms in schizophrenia was discussed.
The effect of an anticholinergic antiparkinsonism drug, benztropine, on the therapeutic course of neuroleptic treatment in 18 schizophrenics was investigated in a double blind cross-over study involving haloperidol and chlorpromazine. Significant therapeutic reversal was observed with benztropine in terms of the social, affective,and cognitive dysfunctions chracteristically seen in schizophrenic psychosis. The hallucinatory behavior and disturbed attention were not so affected. The aspects of the clinical picture to show significant nontherapeutic change with benxtropine differed with the stage of treatment and seemed to be determined by the kinetics of the therapeutic process. The effect was one of exacerbation of the disorder and not a toxic confusional state sometimes associated with anticholinergic drugs. The practical and theoretical significance of these findings was discussed. It was suggested that the benztropine reversal of therapeutic changes provided a valuable pharmacological model for understanding the neurobiological basis of schizophrenic decompensation and its restitution with neuroleptics. The reported data were considered as indirect evidence suggesting that cholinergic neuronal mechnisms are involved in both of these processes. It was speculated that these mechanisms may well be the cholinergic suppressor systems, such as the periventricular catecholamine pathways in the limbic organization and bsal ganglia known to be affected by neuroleptics.
Two developmentally based tests were devised to study the nature of schizophrenic cognitive dysfunction within a psychopharmacolgical framework and to relate the data to developmental and psychophysiological models. The Colour-Form Preference Test was designed to evaluate cognitive style in terms of early maturational stages and provided a subscale for assessing arousal-related cognitive growth. The Egocentricity of Thought Test, adapted from Piaget's developmental study of right-left positional concepts, enabled investigation in terms of the later stages of cognitive growth. These and other clinical measures were taken of schizophrenic patients at various points of treatment and also administered to a non-psychotic comparison group. Test results supported their validity, reliability, longitudinal sensitivity and capacity for nosological and prognostic discriminations. The data also suggested a distinction between two components of schizophrenic cognitive dysfunction -- one drug-sensitive, which could be considered as arousal-related, and the other drug-resistant, which might best be described as developmental. A two-factor model encompassing the psychophysiological and developmental hypotheses is thus offered as a more comprehensive representation of the cognitive disorder.
The Colour Form Representation Test (CFR) was devised as one of a series of developmentally rooted objective measures of schizophrenic cognitive dysfunction. Based on the observations of Piaget and others in relation to the conceptual use of colour, form and representational cues, it provided a four-level response hierarchy corresponding to the preverbal and early verbal stages of cognitive growth. The CFR was tested with 66 schizophrenics and 42 non-psychotic subjects and found to distinguish between these two groups and among schizophrenic subtypes. It showed significant correlations with measures of cognitive and attentional dysfunction and, longitudinally, was observed to be a reliable instrument that reflected the differential therapeutic outcome of various schizophrenic groups. The research potential of the CFR and its relevance to developmental and psychophysiological theories of schizophrenic cognitive disorder were discussed.
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