This study investigated the association between the severity of Tourette Syndrome (TS) and comorbid tendencies (Attention Deficit Hyperactivity Disorder (ADHD), Obsessive-Compulsive Disorder (OCD), and rage), maternal differential treatment, fairness evaluation of maternal differential treatment, and communication with both sibling and family relationships. Fifty-five mothers and healthy siblings of individuals with Tourette Syndrome participated in the study. The parents provided information regarding family demographics and the severity of Tourette Syndrome and comorbid tendencies, and the healthy siblings completed the sibling and family relationship questionnaires. The questionnaires were posted on a secure website, where the parents and healthy siblings could complete the online measures via internet connections. <br /><br /> The study revealed several important findings. The results showed significant associations between the severity of Tourette Syndrome and comorbid OCD, ADHD and rage tendencies thus suggesting that studying Tourette Syndrome without considering comorbidity would be unrealistic. Additionally, communication regarding Tourette Syndrome between the healthy siblings and their parents played an important role with respect to sibling and family relationships. Communication between the healthy siblings and their parents predicted more warmth between the healthy siblings and their sibling with Tourette Syndrome as well as more family cohesion and adaptability as reported by the healthy siblings. Communication had a significant moderating effect on both severity of Tourette Syndrome and healthy siblings' fairness evaluation of maternal differential treatment in predicting family relationships. When the sibling had less severe Tourette Syndrome, the healthy siblings reported more family adaptability when they had more communication with their parents, and reported less family adaptability when they had less communication with their parents. The results also indicated that when healthy siblings perceived their maternal differential treatment to be unfair, they reported more family cohesion when they had more communication with their parents, and reported less family cohesion when they had less communication with their parents. The study did not support the negative impact of maternal differential treatment on sibling relationships; however, the results confirmed the previous findings regarding the moderating effect of fairness evaluation on maternal differential treatment in predicting sibling relationships. When the sibling with Tourette Syndrome was favored, the healthy siblings reported more sibling warmth when they perceived the favouritism (maternal differential treatment) to be fair. Furthermore, the results showed that healthy siblings' perceptions of maternal differential treatment could predict cohesion and adaptability in the family. The more the healthy siblings reported being treated differently by their mothers, the less cohesion and adaptability they reported in their families. <br /><br /> The present study supported previous studies in finding that sibling conflict decreased with age. The results also highlighted the role of age in moderating the effects of communication and maternal differential treatment in predicting sibling conflict. When healthy siblings had more communication with their parents they reported more conflict with their sibling with Tourette Syndrome when they were younger, and reported less sibling conflict with their sibling with Tourette Syndrome when they were older. Furthermore, when healthy siblings were favored by their mothers, they reported more conflict with their sibling with Tourette Syndrome when they were younger than when they were older, thereby emphasizing the importance of developmental differences in dynamics between the siblings. The significant contributions of the study include underlining the importance of communication, the relationship between Tourette Syndrome and comorbid conditions, and healthy siblings' perceptions of sibling and family relationships.

This study investigated the association between the severity of Tourette Syndrome (TS) and comorbid tendencies (Attention Deficit Hyperactivity Disorder (ADHD), Obsessive-Compulsive Disorder (OCD), and rage), maternal differential treatment, fairness evaluation of maternal differential treatment, and communication with both sibling and family relationships. Fifty-five mothers and healthy siblings of individuals with Tourette Syndrome participated in the study. The parents provided information regarding family demographics and the severity of Tourette Syndrome and comorbid tendencies, and the healthy siblings completed the sibling and family relationship questionnaires. The questionnaires were posted on a secure website, where the parents and healthy siblings could complete the online measures via internet connections. <br /><br /> The study revealed several important findings. The results showed significant associations between the severity of Tourette Syndrome and comorbid OCD, ADHD and rage tendencies thus suggesting that studying Tourette Syndrome without considering comorbidity would be unrealistic. Additionally, communication regarding Tourette Syndrome between the healthy siblings and their parents played an important role with respect to sibling and family relationships. Communication between the healthy siblings and their parents predicted more warmth between the healthy siblings and their sibling with Tourette Syndrome as well as more family cohesion and adaptability as reported by the healthy siblings. Communication had a significant moderating effect on both severity of Tourette Syndrome and healthy siblings' fairness evaluation of maternal differential treatment in predicting family relationships. When the sibling had less severe Tourette Syndrome, the healthy siblings reported more family adaptability when they had more communication with their parents, and reported less family adaptability when they had less communication with their parents. The results also indicated that when healthy siblings perceived their maternal differential treatment to be unfair, they reported more family cohesion when they had more communication with their parents, and reported less family cohesion when they had less communication with their parents. The study did not support the negative impact of maternal differential treatment on sibling relationships; however, the results confirmed the previous findings regarding the moderating effect of fairness evaluation on maternal differential treatment in predicting sibling relationships. When the sibling with Tourette Syndrome was favored, the healthy siblings reported more sibling warmth when they perceived the favouritism (maternal differential treatment) to be fair. Furthermore, the results showed that healthy siblings' perceptions of maternal differential treatment could predict cohesion and adaptability in the family. The more the healthy siblings reported being treated differently by their mothers, the less cohesion and adaptability they reported in their families. <br /><br /> The present study supported previous studies in finding that sibling conflict decreased with age. The results also highlighted the role of age in moderating the effects of communication and maternal differential treatment in predicting sibling conflict. When healthy siblings had more communication with their parents they reported more conflict with their sibling with Tourette Syndrome when they were younger, and reported less sibling conflict with their sibling with Tourette Syndrome when they were older. Furthermore, when healthy siblings were favored by their mothers, they reported more conflict with their sibling with Tourette Syndrome when they were younger than when they were older, thereby emphasizing the importance of developmental differences in dynamics between the siblings. The significant contributions of the study include underlining the importance of communication, the relationship between Tourette Syndrome and comorbid conditions, and healthy siblings' perceptions of sibling and family relationships.