Joanna Katsanis

Anhedonia and Perceptual Aberration in First-Episode Psychotic Patients and Their Relatives

One hundred eighteen psychiatric patients, each experiencing his or her first lifetime episode of psychosis, 125 of their first-degree relatives, and 155 normal subjects were assessed using the physical anhedonia, social anhedonia, and perceptual aberration scales of Chapman et al. (1976, 1978). We hypothesized that psychotic subjects would obtain higher scores on these scales than their relatives and the controls, and we expected the group of relatives to score more deviantly than the normal controls. The physical anhedonia and social anhedonia scales successfully differentiated the psychiatric patients from the relatives and the latter from the normal subjects. These findings testify to the construct validity of the scales and suggest that they tap a predisposition to psychosis. Unexpectedly, the relatives scored lower on the perceptual aberration scale than did the normal controls, perhaps because the relatives adopted a defensive response set.

Psychometric Detection of Schizotypy: Perceptual Aberration and Physical Anhedonia in Relatives of Schizophrenics

We administered scales of Perceptual Aberration (PERAB) and Physical Anhedonia (PHYSAN), traits that may be related to risk for schizophrenia, to 54 schizophrenics, 146 of their first-degree relatives (evaluated for schizophrenia-related disorders), and 178 normal subjects (screened for psychotic disorders in them or their relatives). For both scales, there was a significant effect of group membership. For the PERAB scale, the schizophrenics had higher scores than the normal subjects, who had higher scores than the relatives. For the PHYSAN scale, schizophrenics had higher scores than their relatives, who had higher scores than the normal subjects. Patterns of familial correlations also suggested that physical anhedonia, but not perceptual aberration, may be familial among schizophrenics and their relatives. The PHYSAN scale, but not the PERAB one, may be a useful indicator of liability for schizophrenia among the relatives of affected probands.

Clinical Correlates of Anhedonia and Perceptual Aberration in First-Episode Patients With Schizophrenia and Affective Disorder

We examined the association between scales measuring physical anhedonia, social anhedonia, and perceptual aberration and premorbid functioning, clinical state, and current level of adjustment in 91 psychotic subjects. The patients were examined at the onset of their first psychotic episode and again 18 months later. For patients with schizophrenia, anhedonia was significantly related to premorbid functioning. No association was found between the scales and clinical state or level of adjustment at intake or follow-up. In affective disorder patients, no correlation was found between premorbid functioning (a stable characteristic) and scale scores, but moderately large correlations emerged between the scales and clinical state and level of adjustment at both assessment times. These results suggest that schizophrenic and affective disorder patients endorse items on these scales for different reasons. We hypothesize that for patients with schizophrenia, the scales assess enduring personality characteristics, whereas for the affective disorder patients, they assess clinical condition at the time of testing.

Acoustic startle reflex in schizophrenia patients and their first-degree relatives: evidence of normal emotional modulation.

We investigated emotional disturbances in 36 schizophrenia patients, 48 of their first-degree relatives, and 56 controls to determine if abnormal affective startle modulation could be associated with genetic risk for schizophrenia. Both patients and relatives had a pattern of startle modulation indistinguishable from controls, with potentiated startle amplitude while viewing negative valence slides and attenuation while viewing positive slides. Patients with flat affect did not differ from those without in startle modulation or slide ratings. The patients and their relatives had lower pleasantness ratings of positive slides and the patients had higher pleasantness ratings of the negative slides than controls. The startle paradigm may not be useful for identifying individuals with a genetic liability for schizophrenia. The results suggest that low-level defensive and appetitive behaviors are unaffected in schizophrenia.

Neuropsychological and oculomotor correlates of spatial working memory performance in schizophrenia patients and controls.

Recent reports of spatial working memory deficits in schizophrenia provide evidence for dorsolateral prefrontal cortical (DLPFC) dysfunction. However, the question of how spatial working memory performance relates to other task impairments in schizophrenia considered reflective of frontal dysfunction, such as the Wisconsin Card Sorting Test (WCST) and smooth pursuit eye tracking, has been largely unexplored. Spatial working memory, as measured by a computerized visual-manual delayed response task (DRT), was evaluated in 42 schizophrenia patients and 54 normal controls. Subjects also completed a battery of neuropsychological and oculomotor tasks. Schizophrenia patients performed as accurately as controls on a no-delay, sensory-motor control condition, but showed a significant impairment in spatial accuracy with the addition of an 8-s delay and verbal distraction task. For the patients, working memory impairment was associated with fewer categories on the WCST, impaired eye tracking, fewer words learned on the Rey Auditory Verbal Learning Test, but not with measures of general cognitive and clinical functioning. Results suggest the presence of a sub-group of schizophrenia patients with common pathophysiology that accounts for the co-variance of several tasks implicating prefrontal dysfunction.

Substance dependence and externalizing psychopathology in adolescent boys with small, average, or large P300 event‐related potential amplitude

To determine if the P300 component of the event-related potential indexes risk for substance use and related disorders, we presented a community sample of 377 16-18-year-old males a visual oddball task and selected 31 subjects with the smallest and 31 subjects with the largest P300 amplitudes. An additional 31 subjects whose amplitudes fell in the middle of the amplitude distribution were assigned to the average group. The small and average amplitude groups were more likely to have alcohol dependence and more symptoms of alcohol dependence than the large amplitude subjects. The small amplitude group had more symptoms of illicit drug dependence than the other groups. There was also a significantly larger proportion of subjects with externalizing disorders in the small amplitude group than in the large P300 group. These findings suggest that P300 amplitude may index a spectrum of risk for disinhibited psychopathology.

Heritability of different measures of smooth pursuit eye tracking dysfunction: A study of normal twins

Research studies have found that smooth pursuit eye movement dysfunction may serve as an index of genetic liability to develop schizophrenia. The heritability of various measures of smooth pursuit eye tracking proficiency and the saccades that occur during smooth pursuit was examined in 64 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs. Two age cohorts were assessed (11-12 and 17-18 years of age). Intraclass correlations indicated significant similarity in the MZ twins for almost all measures in both age cohorts, whereas few of the DZ twin correlations attained significance. Biometrical modeling indicated that genetic mechanisms influence performance on both global and specific eye tracking measures, accounting for about 40% to 60% of the variance. These findings suggest that the underlying brain systems responsible for smooth pursuit and saccade generation during pursuit are under partial genetic control.

Emotional modulation of the startle reflex in twins: preliminary findings

This study investigated twin similarity in general startle reflex reactivity and emotional modulation. Seventeen monozygotic (MZ) and 12 dizygotic (DZ) male twin pairs received startling acoustic stimuli while viewing emotionally positive, negative and neutral slides. Electromyographic (EMG) responses were recorded from the orbicularis oculi. Members of MZ twin pairs had similar response amplitudes under all three valence conditions. In addition, modulation scores for the positive and negative conditions, representing the percent change in response amplitude between the affective and the neutral conditions, also showed significant similarity within MZ twin pairs. Overall, members of DZ twin pairs were not found to be significantly similar of any of the measures. These preliminary findings suggest that emotional modulation of the startle reflex shows familial resemblance within MZ pairs. Given the lack of resemblance between DZ twins, it is tentatively suggested that affective modulation may be under partial genetic control.

Development of oculomotor functioning in preadolescence, adolescence, and adulthood

We examined developmental differences in smooth pursuit eye tracking proficiency in a large sample of preadolescent, adolescent, and adult males. Smooth pursuit was quantified using general measures of oculomotor functioning and by examining the frequency and dynamic characteristics of specific saccadic events. Examination of age effects using general measures indicated that, by late adolescence, the smooth pursuit system reached adult levels of functioning. No significant differences were found between the adolescent and adult groups on most global measures. However, both groups had better eye tracking than the preadolescent group, suggesting that during preadolescence the oculomotor system is still developing and is not yet capable of optimal performance. Examination of the frequency and dynamic characteristics of the saccadic events yielded additional information regarding the nature of the smooth pursuit eye tracking differences of the three age groups.

The association between P300 and age from preadolescence to early adulthood

The present study examined the latency and amplitude of P300 in a large sample of subjects between 11 and 21 years old. The P300 components of the visual event-related potential showed consistent and significant age-related changes. Peak amplitude was found to diminish with increasing age, whereas peak latency decreased. Our data indicate that a linear relationship best explains the association between age and P300 amplitude and latency. The changes in P300 amplitude and latency across the different ages are likely to reflect developmental changes in mental processing that are not due to a decrease in general cortical reactivity with increasing age or the result of subject noncompliance.