Although premonitory sensory phenomena (PSP) and suppressibility of tics (SPT) are important in Tourette syndrome not only when behavioural therapeutic approaches in children are considered, there is a lack of developmental information on these phenomena. Therefore, a cross‐sectional survey of these factors in children and adolescents was carried out. Rates of PSP and SPT were gathered using a questionnaire for the assessment of Tourette syndrome. The 254 outpatients (212 males, 42 females) with Tourette syndrome investigated had an age range of 8 to 19 years, normal intelligence, and diagnosis according to DSM‐IV‐TR/ICD‐10. To test for developmental effects, the total group was stratified into three age groups (8 to 10, 11 to 14, and 15 to 19 years). Data were statistically evaluated using ?² tests. Of the 254 participants, 37% reported PSP, while 64% were able to suppress their tics. Only a subgroup of 119 patients gave unequivocal answers to both questions and only 60% of these experienced both PSP and SPT. Statistically significant stepwise increases were found at two different age levels. One was around 10 years (PSP‘Yes’or‘No’and SPT), the other around age 14 (PSP‘Yes’). There was no influence of tic duration and age at tic onset on PSP/SPT. The reported data suggest that PSP is experienced rarely in younger children with Tourette syndrome and is not a necessary prerequisite for SPT. Increasing PSP with age merely seems to reflect cognitive development rather than intrinsic aspects of Tourette syndrome. In children under 10 years of age, SPT might require more awareness of tics than in older age groups. Developmental aspects of PSP and SPT should be taken into consideration when studies of cognitive behavioural treatment for children and adolescents with Tourette syndrome are planned.

Low serotonergic (5-HT) activity correlates with increased impulsive-aggressive behavior, while the opposite association may apply to cognitive impulsiveness. Both types of impulsivity are associated with attention-deficit/hyperactivity disorder (ADHD), and genes of functional significance for the 5-HT system are implicated in this disorder. Here we demonstrate the separation of aggressive and cognitive components of impulsivity from symptom ratings and test their association with 5-HT and functionally related genes using a family-based association test (FBAT-PC). Our sample consisted of 1180 offspring from 607 families from the International Multicenter ADHD Genetics (IMAGE) study. Impulsive symptoms were assessed using the long forms of the Conners and the Strengths and Difficulties parent and teacher questionnaires. Factor analysis showed that the symptoms aggregated into parent- and teacher-rated behavioral and cognitive impulsivity. We then selected 582 single nucleotide polymorphisms (SNPs) from 14 genes directly or indirectly related to 5-HT function. Associations between these SNPs and the behavioral/cognitive groupings of impulsive symptoms were evaluated using the FBAT-PC approach. In the FBAT-PC analysis for cognitive impulsivity 2 SNPs from the gene encoding phenylethanolamine N-methyltransferase (PNMT, the rate-limiting enzyme for adrenalin synthesis) attained corrected gene-wide significance. Nominal significance was shown for 12 SNPs from BDNF, DRD1, HTR1E, HTR2A, HTR3B, DAT1/SLC6A3, and TPH2 genes replicating reported associations with ADHD. For overt aggressive impulsivity nominal significance was shown for 6 SNPs from BDNF, DRD4, HTR1E, PNMT, and TPH2 genes that have also been reported to be associated with ADHD. Associations for cognitive impulsivity with a SERT/SLC6A4 variant (STin2: 12 repeats) and aggressive behavioral impulsivity with a DRD4 variant (exon 3: 3 repeats) are also described. A genetic influence on monoaminergic involvement in impulsivity shown by children with ADHD was found. There were trends for separate and overlapping influences on impulsive-aggressive behavior and cognitive impulsivity, where an association with PNMT (and arousal mechanisms affected by its activity) was more clearly involved in the latter. Serotonergic and dopaminergic mechanisms were implicated in both forms of impulsivity with a wider range of serotonergic mechanisms (each with a small effect) potentially influencing cognitive impulsivity. These preliminary results should be followed up with an examination of environmental influences and associations with performance on tests of impulsivity in the laboratory.

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that starts in childhood and frequently persists in adults. Several theories postulate deficits in ADHD that have effects across many executive functions or in more narrowly defined aspects, such as response inhibition. Electrophysiological studies on children, however, indicate that ADHD is not associated with a core deficit of response inhibition, as abnormal inhibitory processing is typically preceded or accompanied by other processing deficits. It is not yet known if this pattern of abnormal processing is evident in adult ADHD. The objective of this paper was to investigate event-related potential indices of preparatory states and subsequent response inhibition processing in adults with ADHD. Two cued continuous performance tasks were presented to 21 adults meeting current criteria for adult ADHD and combined type ADHD in childhood, and 20 controls. The ADHD group exhibited significantly weaker orienting attention to cues, cognitive preparation processes and inhibitory processing. In addition, we observed a strong correlation between the resources allocated to orienting to cues and the strength of the subsequent response strength control processes, suggesting that orienting deficits partly predict and determine response control deficits in ADHD. These findings closely resemble those previously found in children with ADHD, which indicate that there is not a core response inhibition deficit in ADHD. These findings therefore suggest the possibility of developmental stability into adulthood of the underlying abnormal processes in ADHD.