Clinical Trial Summary
Schizophrenia (SZ) is a chronic, severe disease resulting in a misperception of reality,
major social withdrawal and cognitive disturbances. Executive dysfunctions are widely
considered as primary determinants of functional outcome. However, classic neuropsychological
executive function measures poorly represent patients' functional outcome and seem
inappropriate to evaluate the real-world functional impact of the disease.
In this perspective, Shallice and Burgess have developed for brain-damaged patients, the
Multiple Errands Test (MET) allowing to assess planning, adaptation, problem solving and
mental flexibility in real life settings, thus better capturing day-to-day abilities and
including contextual (social, perceptive) influences. Setting the assessment outside the
laboratory can help to identify subtle executive impairment not systematically expressed in
standard care conditions and consequently improve the future care solutions. MET is based on
the Supervisory Attentional System model of executive functioning and attention control that
specifies how thought and action schema become activated or suppressed for routine and
non-routine circumstances.
MET has been designed to measure real-world executive performance confronting the
participants to unpredictable affordances and interpersonal interactions while planning and
problem solving. Patients are asked to accomplish several tasks of variable complexity in an
unknown commercial district. Severals rules must be respected and thus an action plan,
strategy formulation, time and space management with very little assistance of the examiner
are required.
Most of the studies involving MET were conceived for patients with acquired brain damage.
LeThiec offered an extensive protocol with the initial scoring system (in terms of
inefficiencies, rule breaks, interpretation failures and task execution failures). Simplified
versions of MET were also suggested to be more suitable in hospital settings. Only one study
was done in SZ including a single patient, it is therefore difficult to draw conclusions
about clinical utility in SZ. To date, no other studies investigated the suitability of MET
in patients with psychosis, while executive impairment is well documented in this population
The investigators hypothesized that the Multiple Errands Test (MET), an ecological assessment
of executive function has a better ability to measure everyday adaptative functioning SZ,
compared to conventional EF assessment methods.
The objectives of this study are: (1) establish normative data and (2) study discriminant
validity of this tool with a large panel of EF measures.
Methods:
60 clinically stable SZ patients and 60 controls will be administered MET, as well as two
measures of executive function: Wisconsin Card Sorting Test - 64, 6 Elements Test. Functional
outcome will be assessed through Behavioural Inventory of Executive Functioning (BRIEF-A),
ECHELLES LAUSANNOISES D'AUTO-EVALUATION DES DIFFICULTES ET DES BESOINS (ELADEB scale) and
Global Assessment of Functioning scale (GAF scale). Clinical measures will be recorded in
patients (Positive And Negative Symptoms Scale (PANSS), State Trait Anxiety Inventory - Y
(STAI-Y A), Diagnostic Interview for Genetic Studies (DIGS) and Family Interview for Genetic
Studies (FIGS)).
Step1: The investigators will first compare patients and controls on all variables of MET and
establish normative data.
Step 2: The investigators will then study the discriminant validity of MET. The investigators
will compare MET with traditional measures of executive functioning. The investigators will
assess the correlation between each executive measure and functional outcome.
