Thought disorder in schizophrenia

Iwanami A, OkajimaY, Kuwakado D, etal. Event-related potentials and thought disorder in schizophrenia. Sc/ zop/ r Res 2000 42 187-191. 

Comparison of ketamine-induced thought disorder in healthy volunteers and thought disorder in schizophrenia. Am J Psychiat 156 1646-1649. 

Shenton ME, Kikinis R, Jolesz FA, Poliak SD, LeMay M, et al. 1992. Abnormalities of the left temporal lobe and thought disorder in schizophrenia. A quantitative magnetic resonance imaging study. N Engl J Med 327(9) 604-612. Smiley JF, Dwork AJ, Hackett TA, Ilievski B, Mancevski B, et al. 2002. Hemispheric comparisons of neuron density and volume of the human primary auditory cortex. Society for Neuroscience Abstracts. 

Vita A, Died M, Giobbio GM, Caputo A, Ghiringhelli L, et al. 1995. Language and thought disorder in schizophrenia Brain morphological correlates. Schizophr Res 15(3) 243-251. 

Caplan, R., Guthrie, D., Tang, B., Komo, S., and Asarnow, R.F. (2000) Thought disorder in childhood schizophrenia replication and update of concept. J Am Acad Child Adolesc Psychiatry 39 771-778. 

Caplan, R., Perdue, S., Tanguay, R, and Fish, B. (1990) Formal thought disorder in childhood onset schizophrenia and schizotypal personality disorder. / Child Psychol Psychiatry 31 1103-1114. 

The positive symptoms are the most responsive to antipsychotic medications, such as chlorpromazine or halo-peridol. Initially, these drugs were thought to be specific for schizophrenia. However, psychosis is not unique to schizophrenia, and frequently occurs in bipolar disorder and in severe major depressive disorder in which paranoid delusions and auditory hallucinations are not uncommon (see Ch. 55). Furthermore, in spite of early hopes based on the efficacy of antipsychotic drugs in treating the positive symptoms, few patients are restored to their previous level of function with the typical antipsychotic medications [2]. 

The transmethylation hypothesis depended on the psychosis of mescaline as an example of how methylated compounds similar in structure to the monoamine neurotransmitters could be psychotogenic, and demonstrated how methionine, the precursor of the methyl donor S-adenosylmethionine, could exacerbate the psychotic symptoms of schizophrenia in patients. This theory was fed by studies of the now notorious pink spot, an amine found in paper chromatography of urine extracts from schizophrenics and thought to be 3,4-dimethoxyphenylethylamine (i.e., O-methylated dopamine). Subsequent studies eventually identified this as another compound or compounds, primarily of dietary origin. Another methylated derivative erroneously proposed to be found in higher quantities in schizophrenia was dimethyltryptamine. This compound is similar in structure to LSD, the hallucinogenic nature of which was the key to the serotonin deficiency hypothesis, which proposed that the known antagonism of serotonin (5-HT) by LSD indicated that psychotic disorders such as schizophrenia may result from a hypofunction of 5-HT. 

In contrast to Kraepelin, who emphasized the progressive course and poor outcome, the Swiss psychiatrist Eugen Bleuler ( 6) used a much broader concept of schizophrenia. Focusing on the thought disorder and the inconsistent, inappropriate, and disorganized affect, he identified four fundamental symptoms ... 

FIG. 5-3. Effects of neuroleptics on thought disorder and behavioral symptoms of schizophrenia. BPRS, Brief Psychiatric Rating Scale TDI, Thought Disorder Index. (From Davis JM, Barter JT, Kane JM. Antipsychotic drugs. In Kaplan HI, Sadock BJ, eds. Comprehensive textbook of psychiatry, 5th ed. Baltimore Williams Wilkins, 1989 1604, with permission.)... 

Younger patients with schizophrenia may be less responsive to pharmacotherapy than adult patients ( 164, 165). Nonresponse to typical antipsychotics is as high as 40% to 50% in some reports. Thought disorder is the most drug-refractory of the classic psychotic symptoms in children and adolescents with schizophrenia. Thus, even when the more florid symptoms (e.g., hallucinations and delusions) abate following treatment with antipsychotics, these patients frequently continue to have substantial impairment in social functioning and scholastic performance. 

Haloperidol is the best-studied antipsychotic medication in children and adolescents with schizophrenia. In a double-blind, placebo- and active-controlled study, haloperidol (2 to 16 mg per day) and loxapine (10 to 200 mg per day) were equally effective and superior to placebo ( 168). This finding was replicated in a placebo-controlled, crossover study of haloperidol (doses of 0.5 to 3.5 mg per day or 0.02 to 0.12 mg/kg per day) in children 5.5 to 12 years of age ( 169). In this study, haloperidol was more effective than placebo in reducing ideas of reference, persecutory ideas, hallucinations, and thought disorder. 

ECT is a treatment that originated in Italy in 1938 for producing convulsions in psychiatric patients. At the time, it was thought that convulsions induced by a variety of methods, including insulin coma and stimulant medication, were useful in treating psychiatric disorders, especially schizophrenia. 

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