Autonomic nervous system markers of psychopathology in childhood-onset schizophrenia.

BACKGROUND

Consistent abnormalities in peripheral indicators of autonomic activity, ie, skin conductance (SC) and heart rate (HR), have been reported in adult-onset schizophrenia. Herein, we use these markers to test the hypothesis of continuity between childhood-onset schizophrenia and adult-onset schizophrenia.

METHODS

Skin conductance and HR were recorded from 21 severely ill children and adolescents (mean age, 14.1 years) with childhood-onset (< or = 12 years) schizophrenia (patient group) and from 54 age-matched controls (control group) during a rest period, a series of innocuous tones, reaction time instructions, and a simple warned reaction time task.

RESULTS

During rest, patients had higher rates of spontaneous SC responses (SCRs) and HRs than controls, but their SC level was marginally lower and declined more slowly over time. Half of the patients, compared with 4% of the controls, failed to give SC-orienting responses to the first 2 tones. Patients who responded had impaired SCR magnitudes, and their habituation was more erratic than that of controls. The increase in SC level and SCR frequency at the onset of the task period was greatly attenuated in the patients, so that both variables were higher in controls. Patients had smaller SCRs and anticipatory HR responses to the reaction time stimuli. Skin conductance nonresponding was associated with negative and total symptoms, and spontaneous SCR frequency was associated with positive symptoms.

CONCLUSIONS

The findings show similar abnormalities in autonomic nervous system activity in childhood-onset schizophrenia to those found in adult chronic schizophrenia, thus supporting the hypothesis of continuity of the childhood and adult forms of the illness. Comparisons with data from other childhood disorders suggest that the combination of low-elicited SC activity with high levels of spontaneous SC activity may be specific to schizophrenia.