Interpretative guidelines for neuropsychiatric measures with dichotomously scored items

Area of Science:

• Geriatric Psychiatry
• Clinical Psychology
• Psychometric Assessment

Background:

• Dichotomously scored items are prevalent in neuropsychiatric assessments.
• Clinical guidelines often use cutoff scores for interpreting these measures, such as for depression.
• The validity of these cutoffs can be compromised if the total score does not significantly exceed chance.

Purpose of the Study:

• To address the confounding problem of interpreting neuropsychiatric scale scores that may not significantly differ from chance.
• To provide recommendations for interpreting scores from the Geriatric Depression Scale (GDS) in relation to chance responding.
• To enhance the accurate assessment of depressive symptomatology, especially in cases of potential random responding or incomplete effort.

Main Methods:

• Statistical analysis of the Geriatric Depression Scale (GDS) scores.
• Evaluation of score significance against a random response pattern.
• Determination of score ranges that do not differ significantly from chance (p > 0.05).

Main Results:

• GDS scores ranging from 11 to 20 were found not to be significantly different from chance.
• This finding suggests that scores in this range require careful consideration and corroborating evidence.
• The study highlights the potential for random responding to influence GDS scores.

Conclusions:

• Blindly applying cutoff scores on measures like the GDS can be misleading.
• Scores between 11 and 20 on the GDS warrant increased reliance on supportive clinical evidence of depressive symptoms.
• These findings are crucial for accurate patient assessment, particularly when response accuracy or effort may be variable.