Sertraline Vs. Placebo in the Treatment of Anxiety in Children and AdoLescents with NeurodevelopMental Disorders

Inclusion Criteria:

1. Outpatients 8-17 years of age, inclusive

2. Females of child bearing potential who are sexually active and agree to usemedically acceptable birth control throughout the study and at least one week postlast dose of study drug.

3. Meet Diagnostic and Statistical Manual of Mental Disorders - DSM-5 criteria for ASD,ADHD, Tic Disorders, or genetic diagnosis of Fragile X, tuberous sclerosis or 22q11deletions.

4. Meet DSM-5 criteria for one of the following anxiety disorders: Separation AnxietyDisorder, Social Anxiety Disorder, Agoraphobia, Generalized Anxiety Disorder, orUnspecified Anxiety Disorder, based on expert clinical interview, supported by theKiddie Schedule for Affective Disorders and Schizophrenia (KSADS; Kaufman et al., 2016). Other specified anxiety disorder is included to account for youth withimpairing anxiety symptoms who may not meet criteria for one of the other anxietydisorders.

5. Have a Clinician's Global Impression-Severity for anxiety (CGI-S; Guy, 1976)) score ≥ 4 (moderately ill) (inter-rater reliability will be done prior to initiation ofenrollment, using videotapes of interviews and vignettes)

6. Have at least phrase speech, to allow for some self-report. So that results can begeneralized to children and youth with NDD and various levels of ability, no IQcut-off will be employed. Full-scale IQ (as measured by the Stanford-Binet) ismeasured to explore its effect on efficacy and safety*

7. If already receiving interventions, must meet the following criteria:

8. If receiving concomitant medications affecting behaviour, must be on a stabledose during the month prior to screening and will not electively modify ongoingmedications for study duration

9. If already receiving stable non-pharmacological behavioural interventions, havestable participation during 3 months prior to screening, and will notelectively modify ongoing interventions

10. Ability to complete assessments in English/French

Exclusion Criteria:

1. Receiving other SSRIs within four weeks of randomization (6 weeks for fluoxetine)

2. Previous treatment with sertraline, at an adequate dose (at least 100mg for 6 weeks,or lower dose and duration if not well-tolerated), associated with no response orsignificant-to-the-participant side effects.

3. Received more than 2 previous appropriate trials of SSRIs with no adequate response

4. Pregnant females or sexually active females on inadequate contraception

5. Serious medical condition that, based on Investigator judgment, might interfere withthe conduct of the study, confound interpretation of the study results, or endangerparticipant. In addition diabetic patients on medications for glycemic control willbe excluded as sertraline may interfere with glycemic control.

6. Hypersensitivity to sertraline or any components of its formulation

7. On Monoamine Oxidase Inhibitors or pimozide (as per product monograph)

8. On concomitant medications known to significantly increase QT interval where thiswould result in unacceptable risk per Investigator judgment.

9. Known congenital QT prolongation

10. HIV, hepatitis B or C, hemophilia, abnormal blood pressure, substance abuse,immunity disorder, major depressive episode or psychosis (as required by HealthCanada)

11. Unable to tolerate venipuncture

12. Unable to swallow capsules

13. Enrolled in another intervention study