Page 192 - ILAE_Lectures_2015

Factitious disorder and dissociative seizures: the concept of unconscious symptom
generation

Factitious disorder (Munchausen’s syndrome) refers to the situation in which a patient is
discovered to be (or admits) deliberately feigning symptoms. The most important feature,
however, and this is critical for the diagnosis, is that in factitious disorder the patient’s
motivation is held to be psychological (understandable in terms of the patient’s psychological
background, personality, dependency needs, etc). By contrast malingering (not a medical
diagnosis) involves fraudulently imitating illness to achieve some obvious practical
advantage (e.g. compensation, to avoid a criminal conviction, to obtain social security
benefits).

By definition, DS are regarded as being involuntary or unconscious. By consensus, the
majority of patients with such seizures are believed to meet this criterion. For some, however,
the fact that experienced clinicians judge this to be the case is not persuasive. For sceptics,
there are three objective features of DS that are worth considering: 1) the majority of patients
are compliant with their antiepileptic drugs (AEDs), often for many years and to the point of
toxicity4,14; 2) when patients are admitted for telemetry the majority have a seizure in a setting
which they must surely recognise involves intensive monitoring; 3) the seizure is usually a
poor imitation of epilepsy. None of these points is by any means conclusive but if deception
is involved, it is of a kind that is difficult to understand.

While psychiatric classification systems assume a dichotomy between conscious and
unconscious symptom generation (implying factitious or dissociative seizures respectively)
the two are best regarded as opposite ends of a continuum. The concept of self deception,
something which at a trivial level most people can relate to, lies somewhere in the middle and
provides a useful paradigm for understanding how subjective experience, and even complex
behaviour, is prone to influences that are not always fully conscious, even in healthy
individuals.

Clinical features of dissociative seizures

Prevalence
From prevalence figures for epilepsy and estimates of the proportion of patients referred to
tertiary clinics who have DS, Benbadis and Allen2 calculated the prevalence of DS to be
between two and 33 per 100,000. However, the true prevalence may be far greater. These
authors based their calculation on the assumption that most patients with DS would find their
way to specialist clinics because their seizures would persist despite AED treatment in
primary care. However, it remains entirely possible that some patients with DS have a
(placebo) response to their first AED prescription and are never referred on for specialist
advice. This possibility is borne out by a recent population-based study that found DS in a
fifth of patients with new-onset seizures, the same proportion of DS reported in specialist
services15.

Demographic characteristics
Some 75% of patients are female3,14,16,17. Seizures typically begin in the late teens or early
20s, although there is a wide range3,14,16. A UK study found a median delay between seizure
onset and diagnosis of three years3, but even longer delays have been reported by others18,19.
Patients with lower educational achievement and of lower socioeconomic groups are
probably overrepresented, although not in comparison with epilepsy.

Clinical assessment
No single semiological feature distinguishes DS from epileptic seizures or vice versa. The
most helpful features, as well as some important pitfalls  symptoms that are commonly