Dissociation

Definition

Dissociation covers phenomena that may not share a mechanism, which is the central difficulty in studying it.

Holmes and colleagues proposed a distinction that has been widely adopted:

• Detachment: depersonalisation, derealisation, out-of-body experience. An altered quality of experience.
• Compartmentalisation: dissociative amnesia, conversion symptoms, identity states. A loss of the ability to deliberately control processes that are otherwise intact.

These have different correlates and probably different mechanisms, and treating them as one construct has muddied the literature.

History

Janet described dissociation in the 1880s and 1890s in terms that anticipate current models closely. The concept then largely disappeared from mainstream psychology for most of the twentieth century, displaced by psychoanalytic repression and then by behaviourism.

It returned in the 1970s and 1980s alongside a sharp rise in diagnoses of multiple personality disorder, and then became entangled in the recovered-memory controversy, which damaged the field's credibility and has left the area unusually polarised.

Theory

Two positions structure the argument about the compartmentalised end.

The trauma model holds that dissociative disorders develop as a response to overwhelming, usually early and repeated, trauma.

The sociocognitive or fantasy model holds that dissociative identity presentations are substantially shaped by suggestion, cultural scripts and iatrogenic influence.

The evidence does not cleanly settle it. Trauma histories are strongly associated with dissociation; so are fantasy proneness and suggestibility; and the associations are not mutually exclusive. Many researchers now hold a position that allows both trauma and social shaping to contribute.

At the detachment end there is less controversy. Depersonalisation as a response to acute threat is well documented and does not require either model.

Research

Dissociative experiences are common at low levels. Clinically significant dissociation is much rarer.

High dissociation predicts worse outcomes in several treatments, though not consistently, and the older clinical rule that dissociation contraindicates trauma-focused work is not well supported by trials.

Measurement is a weak point. The most-used scale mixes detachment and compartmentalisation items and absorption items that are not pathological at all.

Applications

Assessment matters most for treatment planning in trauma work and for distinguishing dissociative seizures from epileptic ones, where misdiagnosis is common and consequential in both directions.

Grounding techniques address detachment; the treatment of compartmentalised presentations is less well evidenced and is the area where practice most outruns trial data.

Criticism

• The construct may not be one thing. Grouping absorption, depersonalisation and identity alteration under one word has held the field back.
• The recovered memory era caused documented harm, and the reckoning with it is incomplete on both sides of the argument.
• Prevalence estimates vary wildly, which usually indicates a measurement problem rather than a real difference between populations.
• Dissociative identity disorder is diagnosed at very different rates in different countries and by different clinicians, which the trauma model alone does not explain.

References

• Holmes, E. A., et al. (2005). Are there two qualitatively distinct forms of dissociation? Clinical Psychology Review, 25(1), 1-23.
• Dalenberg, C. J., et al. (2012). Evaluation of the evidence for the trauma and fantasy models of dissociation. Psychological Bulletin, 138(3), 550-588.
• Lynn, S. J., et al. (2014). The trauma model of dissociation: Inconvenient truths and stubborn fictions. Psychological Bulletin, 140(3), 896-910.
• Bernstein, E. M., & Putnam, F. W. (1986). Development, reliability, and validity of a dissociation scale. Journal of Nervous and Mental Disease, 174(12), 727-735.