Table 2: Studies exploring the physiopathology of psychomotor retardation.

AuthorsSample (criteria)TreatmentsMethodsResults

Bench et al. 1993 [72]Depressed = 40
(RDC)
Controls = 30
Antidepressant
Neuroleptic
Mood stabilizer
SPECT
Item “retardation” SADS
Negative correlation between PMR and CBF in the LDPFC and angular gyrus
Hickie et al. 1995 [73]MDD = 39
(RDC)
Controls = 19
Antidepressant
ECT
Mood stabilizer
MRI
Neuropsychological assessment
(TMT, DSST)
Association PMR/white matter hyperintensities
Hickie et al. 1999 [74]MDD = 25
(RDC)
NSSPECT
Reaction time
Negative correlation between reaction time and neostriatal blood flow
Videbech et al. 2002 [75]MDD = 42
(DSM IV)
Controls = 15
Antidepressant
Neuroleptic
Mood stabilizer
PET
MRI
SRRS
Negative correlation between SRRS and CBF in dorsolateral and supraorbital prefrontal cortices
Naismith et al. 2002 [76]MDD = 46
(DSM IV)
Controls = 20
AntidepressantSPECT
Stroop test
Negative correlation between PMR and blood flow in the LDPFC and angular gyrus
Walther et al. 2012 [77]MDD = 20
(DSM IV)
Controls = 19
Antidepressant
Mood stabilizer
Benzodiazepine
Hypnotic
MRI
Actigraphy
Positive association between activity level and CBF in the right orbitofrontal cortex and inverse association in the left supplemental motor area
Walther et al. 2012 [78]MDD = 21
(DSM IV)
Controls = 21
Antidepressant
Mood stabilizer
Benzodiazepine
Hypnotic
Diffusion tensor imaging
Actigraphy
Negative association between activity level and fractional anisotropy underneath the left primary motor cortex
Bracht et al. 2012 [79]MDD = 21
(DSM IV)
Controls = 21
Antidepressant
Mood stabilizer
Benzodiazepine
Hypnotic
Diffusion tensor imaging
Actigraphy
Alteration of white matter organisation of rostral anterior cingulate cortex-presupplementary motor area and dLPFC-presupplementary motor area pathways
Shah et al. 1997 [80]MDD = 15
(DSM IV)
Controls = 15
Antidepressant
Benzodiazepine
Mood stabilizer
IBZM-SPECT
CANTAB
HDRS
Negative correlation between IBZM binding and psychomotor speed, but not with the HDRS retardation item
Austin et al. 2000 [81]MEL = 7
(DSM IV)
Controls = 30
NoneSingle administration of the dopamine agonist apomorphine: motor and neuropsychological tests before and after injectionNo improvement of motor and cognitive performance after apomorphine injection
Martinot et al. 2001 [82]MDD = 12
(DSM IV)
Controls = 7
SRRIPET
MRI
Retarded patients: reduction of fluorodopa uptake in the left caudate
Meyer et al. 2006 [83]MDD = 21
(DSM IV)
NonePET
Neuropsychological assessment
Correlation between putamen D2 binding potential and motor performances
Bajbouj et al. 2006 [84]MDD = 20
(DSM IV)
Controls = 20
NoneTMS
CORE
Reduced GABAergic tone in MDD
Mitchell et al. 1996 [85]MEL = 20
(DSM IV/CORE)
Controls = 20
Antidepressant
Neuroleptic
Dexamethasone suppression test
HDRS
CORE
Negative correlation between CORE score and cortisol level
van Londen et al. 1997 [86]MDD = 48
(DSM III-R)
Controls = 30
BenzodiazepineAVP concentrations
Actimetry
MADRS
Correlation between AVP concentrations and motor activity during wakefulness
van Londen et al. 1998 [87]MDD = 52
(DSM III-R)
Controls = 48
BenzodiazepineAVP concentrations
SRRS
MADRS
Plasma AVP concentrations:
severe retarded MDD > mild/no retarded MDD

AVP: arginine vasopressin; CANTAB: computerised psychometric testing battery; CBF: cerebral blood flow; DSM: Diagnostic and Statistic manual of Mental Disorders; DSST: digit symbol substitution test; ECT: electroconvulsivetherapy; IBZM-SPECT: iodo-methoxybenzamide-single photon emission tomography; HDRS: Hamilton Depression Rating Scale; LDLPFC: Left Dorsolateral Prefrontal Cortex; MEL: melancholic; MDD: major Depressive Disorder; MRI: magnetic resonance imaging; PET: positron emission Tomography; PMR: psychomotor retardation; RDC: Research Diagnosis Criteria; SADS: Schedule for Schizophrenia and Affective Disorder; SPECT: single photon emission computed tomography; SRRI: selective serotonin reuptake inhibitor; SRRS: Salpetrière Retardation Rating Scale; TMS: transcranial magnetic stimulation; TMT: trail making test.