PDQ-4
Personality Diagnostic Questionnaire (PDQ-4)
The PDQ-4 is a self-report screening questionnaire for personality disorders designed for clinical or research use. It assesses the 10 personality disorders defined in the DSM-IV, as well as two additional categories, using a categorical approach. Each disorder is associated with a minimum threshold of pathological answers at which the result is considered positive. Although it offers good sensitivity, particularly for borderline personality, its specificity remains limited, which means it should be used as an initial screening tool. Interpretation must always be supplemented by a thorough clinical assessment.
- Number of questions
- 118 questions
- Estimated duration
- 20 minutes
- Language
- English
- Original name
- Personality Diagnostic Questionnaire
- Target audience
- Adults and adolescents
- Authors
- Hyler SE, Rieder RO (1994)
- Category
- Personality disorders
Preview of the 118 questions
Scoring & interpretation
Start by checking whether the questionnaire is valid. To do so, look at the answers to questions 64 ("a nuclear war might not be such a bad idea") and 76 ("I have lied a lot on this questionnaire"). The questionnaire is considered invalid if the patient answers "true" to question 76, or if they answer "true" to both 64 and 76. In all other cases, it is valid.
If the questionnaire is valid, then evaluate the "Too Good" scale (questions 12, 25, 38, and 51). Activation of this scale suggests that the patient may have tried to give an excessively positive or unrealistic picture of themselves. This attitude can bias the expression of certain pathological traits. The results should then be interpreted with caution and ideally supplemented by a clinical interview.
Then go on to evaluate the different personality disorders one by one. Each disorder has a minimum number of "true" answers to reach, called the "threshold", which is indicated on the scoring sheet.
A special case concerns antisocial personality. Criterion B must necessarily be checked "true". This item can only be validated if at least three of the behaviors listed in question 99 are themselves checked "true". Then, for antisocial personality to be considered present, at least three other items among those listed in the antisocial column must be checked.
Another special case: item 98 (borderline personality impulsivity) can only be counted if at least two of its sub-questions are checked "true".
Finally, item 60 appears in two columns (schizoid and schizotypal). If it is checked "true", it should be counted only once in the total score.
The PDQ-4+ total score is calculated by adding up all the pathological ("true") answers, except for the items of the two validity scales ("too good" and "suspect questionnaire"). The maximum score is 93. Some authors consider a score of 25 or higher to be indicative of one or more personality disorders, and a score of 28 or higher to be a more discriminating cutoff.
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The more votes a questionnaire gets, the sooner it becomes available. With 0 votes, it's planned for the week of Jan 12, 2027.