Recent findings demonstrated significant overlaps among major psychiatric disorders on multiple neurocognitive domains. However, it is not clear which are the cognitive functions that contribute to this phenomenon.

To find the optimal clustering solution using the two-step cluster analysis on a sample of psychiatric patients.

To classify into subgroups a cross-diagnostic sample of psychiatric inpatients on the basis of their neurocognitive profiles.

Seventy-one patients with psychotic, bipolar, depressive and personality disorders hospitalised at Psychiatric Diagnosis and Care Service of Bufalini Hospital of Cesena participated in the study. The symptomatology was assessed using Health of the Nation Outcome Scales-Roma and Brief Psychiatric Rating Scale. Cognitive functions were evaluated using Tower of London, Modified Wisconsin Card Sorting Test, Judgment and Verbal Abstract Tasks test, Raven matrices, Attentional Matrices, Stroop Test and Mini Mental State Examination. Two-step cluster analysis was conducted using the standardized scores of each neurocognitive test.

Two groups were obtained:– group 1, with good cognitive performances;– group 2, with almost all subjects having impaired cognitive performances.

Executive functions and attention are the major determinants of the cluster solution. The clusters did not differ on socio-demographic correlates. Different diagnoses were equally distributed amongst the clusters.

Two-step cluster analysis was useful in identifying subgroups of psychiatric inpatients with different cognitive functioning, overcoming other cluster techniques limitations. According to former literature, these results confirm a continuum of severity in cognitive impairment across different psychiatric disorders.

The authors have not supplied their declaration of competing interest.

Eye movements are used in several studies as a biomarker in order to evaluate cortical alterations in psychiatric disorders. Pursuit eye movements’ deficits were found both in schizophrenia and in affective disorder patients. Nevertheless, these findings are still controversial.

Set up a system to record and evaluate the eye movements in psychiatric patients.

To verify the applicability of a smooth pursuit task in a sample of psychiatric inpatients and to prove its efficiency in discriminating patient and control group performance.

A sample of psychiatric inpatients was tested at psychiatric service of diagnosis and care of AUSL Romagna-Cesena. Eye movement measures were collected at a sampling rate of 60 Hz using the eye tribe tracker, a bar plugged into a PC, placed below the screen and containing both webcam and infrared illumination. Subjects underwent to a smooth pursuit eye movement task. They had to visually follow a white dot target moving horizontally on a black background with a sinusoidal velocity. At the end of the task, a chart of the eye movements done is shown on the screen. Data are off-line analyzed to calculate several eye movement parameters: gain, eye movement delay with respect to the movement of the target, maximum speed and number of saccades exhibited during pursuit.

Patients compared to controls showed higher delay and lower gain values.

Findings confirm the adequacy of this method in order to detect eye movement differences between psychiatric patients and controls in a smooth pursuit task.

The authors have not supplied their declaration of competing interest.