Following a 1-week baseline, 19 normal boys (mean age 9.8 +1.8 years) ingested either caffeine (5... more Following a 1-week baseline, 19 normal boys (mean age 9.8 +1.8 years) ingested either caffeine (5 mg/kg) or placebo twice a day for a 2-week period per condition in a double-blind crossover study (total study duration of 5 weeks) to study the behavioral, autonomic and side effects of caffeine. Mothers of the whole sample and children who were low caffeine users could distinguish between drug conditions by side effects. Caffeine increased autonomic reactivity of low users only. Behavioral and autonomic results were ambiguous for high users indicating possible caffeine withdrawal symptoms. While 'caffeinism' may occur in children, either self-selection and/or tolerance may prevent its occurrence in naturally selected diets.
The Journal of Abnormal and Social Psychology, 1959
The present experiment investigated the size estimations of pictures imbued with two kinds of af... more The present experiment investigated the size estimations of pictures imbued with two kinds of affective meaning by schizophrenics with good premorbid adjustments with poor premorbid adjustments, and normals. Positive and negative affective meanings were built into two pictures by means of a prior task involving differential reinforcement. In addition, size estimates were made of pictures depicting a mother scolding a
This study test the effects on autonomic nervous system (ANS) activity of two doses (0.25 mg/kg a... more This study test the effects on autonomic nervous system (ANS) activity of two doses (0.25 mg/kg and 0.50 mg/kg) of dextroamphetamine in normal men. Skin conductance and heart rate were recorded during rest, tone presentation, and a reaction time task. Compared to placebo, dextroamphetamine increased both skin conductance and heart rate indices of arousal, slowed habituation, and reduced ANS responsivity selectively to more important vs. less important stimuli. The last result differs from previous findings on hyperactive and normal boys. The pattern of ANS effects closely resembles findings on drug-free schizophrenics, suggesting that it may be a matter for biologic changes occurring in amphetamine psychosis and spontaneous psychotic episodes.
Journal of Clinical and Experimental Neuropsychology, 1999
The nature of deficits in attention in closed head injury (CHI) was studied by three reaction tim... more The nature of deficits in attention in closed head injury (CHI) was studied by three reaction time (RT) paradigms given to 20 patients who had a CHI 2 or more years previously and to 25 controls. We studied the effects of temporal uncertainty by varying the length and regularity of the preparatory interval, the effects of stimulus modality uncertainty on simple RT to tones and lights, and the effects of response selection in choice RT. The CHI group showed slower and more variable RT than controls under all conditions. In addition, a long preparatory interval on the preceding trial retarded RT more in the CHI group, and they showed greater effects of stimulus modality uncertainty. Both of these findings suggest a difficulty in shifting attention to unexpected stimuli. These greater effects on RT of variations of attention or preparation in CHI may account for their greater within-subject variability possibly due to frontal lobe damage.
European Archives of Psychiatry and Clinical Neuroscience, 1992
Summary The anxiogenic effects of yohimbine, a specific alpha-2-receptor antagonist were examined... more Summary The anxiogenic effects of yohimbine, a specific alpha-2-receptor antagonist were examined by administering 20 mg yohimbine orally to 8 panic patients on placebo treatment, 7 panic patients on alprazolam treatment and 12 controls using a double-blind randomized design, instructions that minimized the expectancy of experiencing a panic attack and two additional structured situations. Yohimbine induced more pronounced increases in
Low electrodermal activity has been proposed as a trait marker for affective disorder. We attempt... more Low electrodermal activity has been proposed as a trait marker for affective disorder. We attempted to determine if low electrodermal activity could be a genetic marker by testing subjects at genetic risk for affective disorder. High-risk subjects, 22 offspring of a parent with bipolar affective disorder, and 27 low-risk controls 15 to 25 years old had skin conductance recorded bilaterally during rest periods, presentation of 10 nonsignal tones, and performance of reaction-time and mental arithmetic tasks. There were no significant differences in skin conductance levels under any condition or in the frequency or amplitude of orienting responses to nonsignal tones. During task periods high-risk subjects showed significantly greater electrodermal activity that was lateralized to the left hand. Self-rated depression was higher in the high-risk group during task periods. The results show that low electrodermal activity is not a likely genetic marker for affective disorder but suggest that autonomic hyperresponsivity, atypically lateralized information processing, and depressive affect occur during mild stress in persons at risk for the development of affective disorder.
STUDIES of the parents of schizophrenics have demonstrated aberrant modes of conceptualizing and ... more STUDIES of the parents of schizophrenics have demonstrated aberrant modes of conceptualizing and thinking in these subjects similar in nature to those shown by schizophrenics themselves. 1-3 Recently Ciarlo et al 4 using a Word Association Test, found the parents of schizophrenics to give more culturally deviant associations than the parents of normal subjects. These studies suggest that thinking disorders are somehow transmitted from parent to child but do not establish the roles of genetic, environmental, or other factors in this transmission. One of the factors which seriously weakens the criticalness of studies in this respect is the fact that the parents tested not only raised their offspring but provided their genetic makeup as well. In the present study an attempt is made to disentangle biological and familial influences on the coincidence of pathological thinking in parent and schizophrenic offspring by comparing
Following a 1-week baseline, 19 normal boys (mean age 9.8 +1.8 years) ingested either caffeine (5... more Following a 1-week baseline, 19 normal boys (mean age 9.8 +1.8 years) ingested either caffeine (5 mg/kg) or placebo twice a day for a 2-week period per condition in a double-blind crossover study (total study duration of 5 weeks) to study the behavioral, autonomic and side effects of caffeine. Mothers of the whole sample and children who were low caffeine users could distinguish between drug conditions by side effects. Caffeine increased autonomic reactivity of low users only. Behavioral and autonomic results were ambiguous for high users indicating possible caffeine withdrawal symptoms. While 'caffeinism' may occur in children, either self-selection and/or tolerance may prevent its occurrence in naturally selected diets.
The Journal of Abnormal and Social Psychology, 1959
The present experiment investigated the size estimations of pictures imbued with two kinds of af... more The present experiment investigated the size estimations of pictures imbued with two kinds of affective meaning by schizophrenics with good premorbid adjustments with poor premorbid adjustments, and normals. Positive and negative affective meanings were built into two pictures by means of a prior task involving differential reinforcement. In addition, size estimates were made of pictures depicting a mother scolding a
This study test the effects on autonomic nervous system (ANS) activity of two doses (0.25 mg/kg a... more This study test the effects on autonomic nervous system (ANS) activity of two doses (0.25 mg/kg and 0.50 mg/kg) of dextroamphetamine in normal men. Skin conductance and heart rate were recorded during rest, tone presentation, and a reaction time task. Compared to placebo, dextroamphetamine increased both skin conductance and heart rate indices of arousal, slowed habituation, and reduced ANS responsivity selectively to more important vs. less important stimuli. The last result differs from previous findings on hyperactive and normal boys. The pattern of ANS effects closely resembles findings on drug-free schizophrenics, suggesting that it may be a matter for biologic changes occurring in amphetamine psychosis and spontaneous psychotic episodes.
Journal of Clinical and Experimental Neuropsychology, 1999
The nature of deficits in attention in closed head injury (CHI) was studied by three reaction tim... more The nature of deficits in attention in closed head injury (CHI) was studied by three reaction time (RT) paradigms given to 20 patients who had a CHI 2 or more years previously and to 25 controls. We studied the effects of temporal uncertainty by varying the length and regularity of the preparatory interval, the effects of stimulus modality uncertainty on simple RT to tones and lights, and the effects of response selection in choice RT. The CHI group showed slower and more variable RT than controls under all conditions. In addition, a long preparatory interval on the preceding trial retarded RT more in the CHI group, and they showed greater effects of stimulus modality uncertainty. Both of these findings suggest a difficulty in shifting attention to unexpected stimuli. These greater effects on RT of variations of attention or preparation in CHI may account for their greater within-subject variability possibly due to frontal lobe damage.
European Archives of Psychiatry and Clinical Neuroscience, 1992
Summary The anxiogenic effects of yohimbine, a specific alpha-2-receptor antagonist were examined... more Summary The anxiogenic effects of yohimbine, a specific alpha-2-receptor antagonist were examined by administering 20 mg yohimbine orally to 8 panic patients on placebo treatment, 7 panic patients on alprazolam treatment and 12 controls using a double-blind randomized design, instructions that minimized the expectancy of experiencing a panic attack and two additional structured situations. Yohimbine induced more pronounced increases in
Low electrodermal activity has been proposed as a trait marker for affective disorder. We attempt... more Low electrodermal activity has been proposed as a trait marker for affective disorder. We attempted to determine if low electrodermal activity could be a genetic marker by testing subjects at genetic risk for affective disorder. High-risk subjects, 22 offspring of a parent with bipolar affective disorder, and 27 low-risk controls 15 to 25 years old had skin conductance recorded bilaterally during rest periods, presentation of 10 nonsignal tones, and performance of reaction-time and mental arithmetic tasks. There were no significant differences in skin conductance levels under any condition or in the frequency or amplitude of orienting responses to nonsignal tones. During task periods high-risk subjects showed significantly greater electrodermal activity that was lateralized to the left hand. Self-rated depression was higher in the high-risk group during task periods. The results show that low electrodermal activity is not a likely genetic marker for affective disorder but suggest that autonomic hyperresponsivity, atypically lateralized information processing, and depressive affect occur during mild stress in persons at risk for the development of affective disorder.
STUDIES of the parents of schizophrenics have demonstrated aberrant modes of conceptualizing and ... more STUDIES of the parents of schizophrenics have demonstrated aberrant modes of conceptualizing and thinking in these subjects similar in nature to those shown by schizophrenics themselves. 1-3 Recently Ciarlo et al 4 using a Word Association Test, found the parents of schizophrenics to give more culturally deviant associations than the parents of normal subjects. These studies suggest that thinking disorders are somehow transmitted from parent to child but do not establish the roles of genetic, environmental, or other factors in this transmission. One of the factors which seriously weakens the criticalness of studies in this respect is the fact that the parents tested not only raised their offspring but provided their genetic makeup as well. In the present study an attempt is made to disentangle biological and familial influences on the coincidence of pathological thinking in parent and schizophrenic offspring by comparing
Uploads
Papers by Theodore Zahn