Measuring observed mental state in acute psychiatric inpatients

Relationships within acute psychiatric units between patient-level experiences and events and fluctuations in mental state have rarely been examined.

Data from a multi-centre service evaluation (11 units, 5,546 admissions) were used to examine mental state patterns and associations with clinical characteristics, events and adverse incidents.

During the 12-month evaluation period, nursing staff completed shift-level ratings using a new rating scale, the observed mental state (OMS) scale, which assessed active psychopathology (emotional distress, disinhibition, psychosis, cognitive impairment) and withdrawal (45,885 sets of day/afternoon shift ratings).

The OMS scale performed satisfactorily and is worth considering elsewhere (e.g., active psychopathology: internal consistency, alpha=0.72; short-term stability, r=0.72; sensitivity to change, adjusted standardised difference, ASD=0.71). Levels of active psychopathology were much higher on shifts in which reportable (ASD=1.47) and less serious aggression occurred (ASD=1.44), compared with other shifts in which pro re nata medications were also administered (ASD=0.76), suggesting that medication usage often followed these events, and possibly that agitation and distress levels either rose rapidly or went initially unnoticed on these shifts. Although mental state improved steadily across the admission, one-fifth of the patients with schizophrenia received OMS psychosis ratings in the moderate to severe range during the days prior to discharge.

Observed mental state ratings were strongly linked with diagnosis and reflected key events and incidents. Routine recording using the OMS scale may assist clinical decision-making and evaluation in acute psychiatric units.