Psychosomatic aspects of movement disorders

Wistar Kyoto and Wistar rats differ in the affective and locomotor effects of nicotine

Anhedonia is a characteristic of clinical depression and has been associated with dysfunction of the mesolimbic dopaminergic system, a system also involved in mediating nicotine reward. To further examine the relationship between anhedonia, clinical depression and nicotine reward, the present experiment determined if Wistar Kyoto (WKY) rats, an animal model of clinical depression, differed from Wistar rats in nicotine conditioned place preference (CPP). Strain differences in nicotine-induced changes in locomotor activity also were determined simultaneously. To determine if strain differences were specific to reward-based learning, nicotine or lithium chloride (LiCl) conditioned taste avoidance (CTA) experiments were conducted. Rats received vehicle or nicotine (0.4 or 0.8 mg/kg) during a multi-trial, biased CPP training procedure or received vehicle, nicotine (0.2, 0.4 or 0.8 mg/kg) or lithium chloride (LiCl; 0.0375, 0.075 or 0.15 M) during a multi-trial CTA training procedure. Whereas both nicotine doses (0.4 and 0.8 mg/kg) initially induced hypoactivity, only the moderate nicotine dose (0.4 mg/kg) induced hyperactivity with repeated administration and produced a CPP in Wistar rats. Both nicotine doses failed to alter locomotor activity or produce a CPP in WKY rats. WKY rats also acquired a LiCl CTA more slowly and less robustly compared to Wistar rats. In contrast, nicotine dose-dependently produced a CTA in both strains and WKY rats were more sensitive to the avoidance effects of nicotine compared to Wistar rats. Collectively, these results suggest that WKY rats show deficits in nicotine reward and specific aversive drug stimuli compared to Wistar rats.

Depression as a spreading adjustment disorder of monoaminergic neurons: a case for primary implication of the locus coeruleus

A model for the pathophysiology of depression is discussed in the context of other existing theories. The classic monoamine theory of depression suggests that a deficit in monoamine neurotransmitters in the synaptic cleft is the primary cause of depression. More recent elaborations of the classic theory also implicitly include this postulate, other theories of depression frequently prefer to depart from the monoamine-based model altogether. We suggest that the primary defect emerges in the regulation of firing rates in brainstem monoaminergic neurons, which brings about a decrease in the tonic release of neurotransmitters in their projection areas, an increase in postsynaptic sensitivity, and concomitantly, exaggerated responses to acute increases in the presynaptic firing rate and transmitter release. It is proposed that the initial defect involves, in particular, the noradrenergic innervation from the locus coeruleus (LC). Dysregulation of the LC projection activities may lead in turn to dysregulation of serotonergic and dopaminergic neurotransmission. Failure of the LC function could explain the basic impairments in the processing of novel information, intensive processing of irrational beliefs, and anxiety. Concomitant impairments in the serotonergic neurotransmission may contribute to the mood changes and reduction in the mesotelencephalic dopaminergic activity to loss of motivation, and anhedonia. Dysregulation of CRF and other neuropeptides such as neuropeptide Y, galanin and substance P may reinforce the LC dysfunction and thus further weaken the adaptivity to stressful stimuli.

Anxiety disorders and depressive disorders preceding Parkinson's disease: a case-control study

We studied the association between preceding psychiatric disorders and Parkinson's disease (PD) using a case-control design. We used the medical records-linkage system of the Rochester Epidemiology Project to identify 196 subjects who developed PD in Olmsted County, Minnesota, during the years 1976-1995. Each case was matched by age (+/-1 yr) and sex to a general population control. We reviewed the complete medical records of cases and control subjects to detect preceding psychiatric disorders. The frequency of psychiatric disorders was higher in cases than in control subjects; the odds ratio was 2.2 for anxiety disorders (95% confidence interval [95% CI] = 1.4-3.4; p = 0.0003), 1.9 for depressive disorders (95% CI = 1.1-3.2; p = 0.02), and 2.4 for both anxiety disorders and depressive disorders occurring in the same individual (95% CI = 1.2-4.8; p = 0.02). When we restricted analyses to disorders present 5 years or more before the onset of motor symptoms of PD, the association with depressive disorders lost statistical significance. However, the association with anxiety disorders remained significant for disorders present 5, 10, or 20 years before onset of motor symptoms. Our results suggest that anxiety disorders and depressive disorders are associated with PD and that the causative process or the risk factors underlying PD are present many years before the appearance of motor symptoms.

Computed tomography and neurological soft signs in obsessive-compulsive disorder

Computed tomography was used to compare the following three groups: obsessive-compulsive disorder (OCD) patients with high scores on a soft neurological sign examination, OCD patients with low soft neurological sign scores, and control subjects. Neuranatomical structures were measured using quantitative volumetric analysis. OCD patients with high soft sign scores had significantly increased ventricular volumes compared with OCD patients with low soft sign scores and control subjects. Caudate and lenticular nucleus volumes did not differ between groups.

Role of the dopaminergic system in depression

A hypothesis implicating dopamine in depression was proposed over 15 years ago (Randrup et al 1975). The identification of multiple new subtypes of dopamine receptors and evolving views regarding the function of the dopamine systems in the brain require a reexamination of this hypothesis. Results from studies in depression, Parkinson's disease, and animal models of depression suggest a deficiency of dopamine in depression. Dopamine precursors, dopamine agonists, and dopamine reuptake inhibitors show therapeutic efficacy in depression. Electroconvulsive therapy (ECT) and standard pharmacological antidepressants enhance dopamine function. Studies using receptor-specific drugs in clinical trials and neuroimaging studies are needed to further clarify the role of dopamine in depression.

Is the concept of frontal-subcortical dementia relevant to schizophrenia?

A syndrome of subcortical dementia has been described in conditions predominantly affecting the basal ganglia or thalamus, structures that have also been implicated in the pathogenesis of schizophrenia. There are similarities between subcortical dementia and the type II syndrome of schizophrenia, in terms of clinical features, pattern of neuropsychological deficits, pathology, biochemistry and data from brain-imaging studies. These similarities raise the possibility that certain schizophrenic symptoms, particularly negative symptoms and disturbance of movement, may reflect subcortical pathology. Neuropsychological deficits of presumed frontal lobe origin have been reported in some schizophrenic subjects. The occurrence of such deficits in a condition in which frontal lobe pathology has not been clearly demonstrated may be explicable in terms of a subcortical deafferentation of the pre-frontal cortex.

Facial dyskinesias

The face is prominently or exclusively involved in several involuntary movement disorders, called "facial dyskinesias," in addition to the common buccolingual form of tardive dyskinesia. This review describes the appearance of the most frequently occurring facial dyskinesias: chorea, dystonia, tremor, and tics. Some new treatments are discussed.