The Somatoform Dissociation Questionnaire addresses somatoform manifestations of dissociation of the personality (Nijenhuis et al., 1996). The 20 item SDQ-20 evaluates the severity of somatoform dissociation. The five item SDQ-5 is a screening instrument for DSM-IV dissociative disorders.

The SDQ-20 includes the SDQ-5. The psychometric characteristics of the SDQ are very satisfactory. The instrument is completed within a few minutes.

The theory of structural dissociation of the personality (Nijenhuis, Van der Hart, & Steele, 2004) proposes that one dissociative proces involves a loss of an individual's capacity to integrate experiences, ideas, and functions, or components thereof. These components include sensations, perceptions, movements, affects, knowledge, and memory. As a result of this integrative failure, two or more different parts of the person emerge. The primary prototypical form of trauma-related structural dissociation is between one part that engages in daily life functions--the apparently normal part of the personality--and another part that is fixated in traumatic experience--the emotional part.

Within this context, another dissociative process can occur that maintains structural dissociation. That is, given a lack of integrative capacity, the apparently normal part can mentally avoid the emotional part to cope with life. For example, a child may lack the capacity to integrate abuse and neglect by family members and may function as an apparently normal part in nonabusive situations, and as an emotional part during abuse.

Apparently normal parts usually have negative somatoform dissociative symptoms such as a lack of body awareness and a lack of bodily feelings. Emotional parts can also have negative somatoform dissociative symptoms that relate to evolutionary derived defenses regarding bodily threat from a person such as trauma-related insensitivity for pain (analgesia), inhibitions of movement (freezing and stilling), lack of body feelings (anaesthesia). These emotional parts, however, also tend to have positive somatoform dissociative symptoms such as experiencing sensations in absence of objective stimuli: pain in some part of the body, a sense of being touched, smelling or tasting something, etcetera. These sensations can be part and parcel of traumatic memories that the emotional part contains.

Structural dissociation does not involve perfect barriers between dissociative parts of the personality. Aspects of one or more emotional parts can intrude one or more apparently normal parts. These intrusions may involve traumatic memories or components thereof, or other phenomena. For example, the emotional part's reactivated traumatic memories can sometimes intrude the apparently normal part, or when the emotional part may want to persue a particular course of action that is different from the apparently normal part's wishes, it may try to control the body's movements.

Click here to access the TEC, a self-report measure addressing potentially traumatizing events. 

References

Nijenhuis, E.R.S., Spinhoven, P., Van Dyck, R., Van der Hart, O., & Vanderlinden, J. (1996). The development and the psychometric characteristics of the Somatoform Dissociation Questionnaire (SDQ-20). Journal of Nervous and Mental Disease, 184, 688-694. 

Nijenhuis, E.R.S. (2009). Somatoform dissociation and somatoform dissociative disorders. In P.F. Dell, & J. O’Neil (Eds.), Dissociation and dissociative disorders: DSM-IV and beyond (pp. 259-277). New York: Routledge.

Download SDQ-5 and SDQ-20

The SDQ-20 is available in the following languages: 

The SDQ-5 consists of the SDQ-20 items 4, 8, 13, 15, and 18.