Baseline child-reported anxiety symptoms as measured by the Preschool Spence Anxiety Scale (PAS). The PAS measures symptom severity of DSMIV anxiety disorders in children (subscales: total, panic and agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, social phobia, separation anxiety, and specific fears). The frequency of symptoms is recorded on a 3-point Likert scale from 0 (never) to 3 (always). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater symptom severity. Higher scores indicate greater symptom severity.

Anxiety symptoms reported by children immediately after the intervention measured using the Spence Preschool Anxiety Scale, (PAS). The PAS measures symptom severity of DSMIV anxiety disorders in children (subscales: total, panic and agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, social phobia, separation anxiety, and specific fears). The frequency of symptoms is recorded on a 3-point Likert scale from 0 (never) to 3 (always). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater symptom severity. Higher scores indicate greater symptom severity.

Child-reported anxiety symptoms at 12 months Measured using the Spence Preschool Anxiety Scale (PAS). The PAS measures symptom severity of DSMIV anxiety disorders in children (subscales: total, panic and agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, social phobia, separation anxiety, and specific fears). The frequency of symptoms is recorded on a 3-point Likert scale from 0 (never) to 3 (always). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater symptom severity. Higher scores indicate greater severity of symptoms.

Baseline Parent-reported depressive symptoms as measured by the Strengths and Difficulties Questionnaire, parent version (SDQ; Goodman, 1997). The SDQ measure examines emotional difficulties (5 items), conduct problems (5 items), hyperactivity (5 items), peer problems (5 items), and prosocial behavior (5 items) in children aged 3 to 16 years. Symptom frequency is recorded on a 3-point Likert scale from 0 (Not true) to 3 (Absolutely true). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater severity of symptoms. Higher scores indicate greater symptom severity.

Depressive symptoms reported by parents inmediately after intervention measured by the Strengths and Difficulties Questionnaire, parent version (SDQ; Goodman, 1997). The SDQ measure examines emotional difficulties (5 items), conduct problems (5 items), hyperactivity (5 items), peer problems (5 items), and prosocial behavior (5 items) in children aged 3 to 16 years. Symptom frequency is recorded on a 3-point Likert scale from 0 (Not true) to 3 (Absolutely true). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater severity of symptoms. Higher scores indicate greater symptom severity.

Depressive symptoms reported by parents at 12 months as measured by the Strengths and Difficulties Questionnaire, parent version (SDQ; Goodman, 1997). The SDQ measure examines emotional difficulties (5 items), conduct problems (5 items), hyperactivity (5 items), peer problems (5 items), and prosocial behavior (5 items) in children aged 3 to 16 years. Symptom frequency is recorded on a 3-point Likert scale from 0 (Not true) to 3 (Absolutely true). A minimum possible score of 0 and a maximum possible score of 114 is obtained. Higher scores indicate greater severity of symptoms. Higher scores indicate greater symptom severity.

Baseline of children's behavioral inhibition measured using the Behavioral Inhibition Questionnaire (BIQ). The BIQ assesses the frequency of children's behavioral inhibition in six contexts across three domains: social novelty (unknown adults, peers, and performance in front of others), situational novelty (unfamiliar situations, preschool/separation), and novel physical activities with a possible risk of injury. This questionnaire has 30 items that are scored on a seven-point scale ranging from 1 (almost never) to 7 (almost always). Item scores are summed to create six scale scores: Unknown Peers, Unknown Adults, Performance Situations, Separation/Preschool, Unknown Situations, and Physically Challenging Situations.

Children's behavioral inhibition was immediately measured after the intervention using the Behavioral Inhibition Questionnaire (BIQ). The BIQ assesses the frequency of children's behavioral inhibition in six contexts across three domains: social novelty (unknown adults, peers, and performance in front of others), situational novelty (unfamiliar situations, preschool/separation), and novel physical activities with a possible risk of injury. This questionnaire has 30 items that are scored on a seven-point scale ranging from 1 (almost never) to 7 (almost always). Item scores are summed to create six scale scores: Unknown Peers, Unknown Adults, Performance Situations, Separation/Preschool, Unknown Situations, and Physically Challenging Situations.

Children's behavioral inhibition was measured at 12 months using the Behavioral Inhibition Questionnaire (BIQ). The BIQ assesses the frequency of children's behavioral inhibition in six contexts across three domains: social novelty (unknown adults, peers, and performance in front of others), situational novelty (unfamiliar situations, preschool/separation), and novel physical activities with a possible risk of injury. This questionnaire has 30 items that are scored on a seven-point scale ranging from 1 (almost never) to 7 (almost always). Item scores are summed to create six scale scores: Unknown Peers, Unknown Adults, Performance Situations, Separation/Preschool, Unknown Situations, and Physically Challenging Situations.

Parental overprotective behavior is assessed with the Parental Overprotection Scale (OP, Edwards et al., 2008). POM evaluates, through 19 items, the overprotective behavior of parents towards their children, related in previous studies to anxiety in preschool children. Symptom frequency is recorded on a 3-point Likert scale, from 0 (not at all) to 4 (very much).

Baseline parental depression, anxiety and stress symptoms Measured by the Depression Anxiety Stress Scales - short version (DASS-21). It contains a set of three self-report scales designed to measure the emotional states of depression, anxiety and stress. Each of the three DASS-21 scales contains 7 items, divided into subscales with similar content. The depression scale assesses dysphoria, hopelessness, devaluation of life, self-deprecation, lack of interest / involvement, anhedonia and inertia. The anxiety scale assesses autonomic arousal, skeletal muscle effects, situational anxiety, and subjective experience of anxious affect. The stress scale is sensitive to levels of chronic nonspecific arousal. It assesses difficulty relaxing, nervous arousal, and being easily upset / agitated, irritable / over-reactive and impatient. Scores for depression, anxiety and stress are calculated by summing the scores for the relevant items.