Validation of the Mood and Anxiety Semi-structured (MASS) Interview for patients with intellectual disabilities

Background When assessing people with intellectual disabilities (ID), using the DSM-IV-TR can be challenging. Frequently, significant clinical data must be obtained from interviews with key informants. A new semi-structured interview tool was developed including behavioural descriptions of each DSM-IV-TR symptom criterion for a number of mood and anxiety disorders. A goal was to provide mental health clinicians with an instrument easy to use in clinical practice that would increase reliable identification of diagnostically important mood and anxiety symptoms. This is especially important given the fact that many experts believe these 'internalizing' clinical syndromes may often be missed in this population, because of characteristic limitations in expressive language skills. Method To establish validity, the Mood and Anxiety Semi-structured (MASS) Interview-derived diagnoses were compared with clinical DSM-IV diagnoses derived from an extensive inpatient evaluation and classifications based on the Hamilton Depression Rating Scale for 93 psychiatric inpatients served on a specialized unit for people with ID and major mental health disorders. Results Agreement with the MASS Interview was high yielding significant kappa coefficients ranging from 0.42 to 0.78. Conclusions The MASS Interview, a semi-structured interview containing behavioural descriptions of DSM-IV symptom criteria, shows promise as a potentially helpful tool in the psychiatric diagnostic evaluation of persons with ID and limited expressive language skills, in the detection of mood and anxiety disorders. The tool also yields a wide breadth of clinical information and is easy for mental health clinicians to use.