Increased motor activity in cycloid psychosis compared to schizophrenia

Although cycloid psychoses share psychopathological features with schizophrenia, their course and outcome are comparable to those seen in bipolar affective disorder. The diagnostic category is of interest because it has been demonstrated that cycloid psychoses can be diagnosed reliably and distinguished from other psychoses based on treatment response and neurophysiology. Despite this, only few studies have investigated the neurobiological differences between cycloid psychoses and schizophrenia, and although hyper- and hypoactivity have been observed in patients with cycloid psychoses, no studies have investigated motor activity in this group to date. Therefore, we aimed to quantify motor activity during the waking hours of the day as assessed by wrist actigraphy in 16 patients with cycloid psychosis and 16 patients with paranoid schizophrenia. All patients were matched for gender and age, and wrist actigraphic assessment took place during acute episodes. The level of activity and proportion of active vs. inactive periods during waking hours were significantly higher in patients with cycloid psychosis. The results of the present study are interpreted in light of a previously reported general arousal in cycloid psychoses that is expressed in motor activity. Our data support the concept of cycloid psychoses as a syndrome with distinct symptomatology and pathophysiology.