The effect of m-CPP on tics and obsessive-compulsive phenomena in Gilles de la Tourette syndrome.
BACKGROUND
Family genetic and phenomenological studies support an interrelationship between Gilles de la Tourette syndrome (GTS) and obsessive-compulsive disorder (OCD). Some authors consider GTS as part of a serotonergically mediated cluster of OCD spectrum disorders.


OBJECTIVE
To study serotonergic mechanisms in GTS, the effect of the relatively selective 5-HT2c agonist meta-chlorophenylpiperazine (m-CPP) was assessed.


METHODS
We studied the behavioural effects of m-CPP on tics, obsessions, compulsions and impulsions of GTS. Twelve medication-free GTS patients (ten men, two women) were included in a single dose 0.5 mg/kg oral m-CPP challenge study with a double-blinded placebo-controlled cross-over design. Global symptom scores, target symptom scores as well as biochemical measures were followed up to 24 h after baseline.


RESULTS
While m-CPP caused a significant rise in plasma cortisol and prolactin levels, no significant effects were found on the tics, obsessions and compulsions. Impulsions showed a trend to ameliorate.


CONCLUSIONS
This study does not support a predominant role for 5-HT on the tics in GTS. The trend of impulsions to ameliorate after m-CPP can be interpreted as circumstantial support for impulsivity-related 5-HT hypofunctionality in GTS. However, the large variability of m-CPP plasma concentrations found in this study casts doubts upon the reliability of m-CPP as a probe for challenge studies.
Cath
D C
DC
Psychiatric Hospital Amsterdam Outpatient Clinic, The Netherlands. ingel@xs4all.nl
Gijsman
H J
HJ
Schoemaker
R C
RC
van Griensven
J M
JM
Troost
N
N
van Kempen
G M
GM
Cohen
A F
AF
D000328:Adult; D000368:Aged; D003192:Compulsive Behavior / Q000188:drug therapy; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009770:Obsessive Behavior / Q000188:drug therapy; D010879:Piperazines / Q000097:blood / Q000627:therapeutic use*; D017366:Serotonin Receptor Agonists / Q000097:blood / Q000627:therapeutic use*; D013981:Tic Disorders / Q000188:drug therapy; D005879:Tourette Syndrome / Q000097:blood / Q000188:drug therapy*
D010879:Piperazines; D017366:Serotonin Receptor Agonists; C015068:1-(3-chlorophenyl)piperazine