Lisdexamfetamine For the Treatment of Conduct Disorder in Children

About 2 in every 100 Australian children have conduct disorder, a serious mental health condition characterised by antisocial behaviours like aggression and rule breaking. This condition leads to big problems not only for the children but also for their families. Despite its major impacts, conduct disorder is not well understood, and treatments are limited. Talk therapy works best, but it's hard to access and is expensive. Current medications can help but often cause unwanted side effects. Stimulant medications (like those used for Attention Deficit/Hyperactivity Disorder or ADHD) may help reduce aggression and impulsive behavior in children with conduct disorder. One medication called lisdexamfetamine shows promise. It is safe and already approved for treating ADHD in children in Australia, and only needs to be taken once a day. Because it's safe and already in use for similar conditions, it could be a promising option for treating conduct disorder in children. This study will test if lisdexamfetamine can reduce conduct disorder symptoms in children aged 10 to 15 years old compared to placebo.

Inclusion Criteria: 1. Aged 10-15 years old (inclusive); 2. Have a current diagnosis of DSM-5 conduct disorder, assessed with the Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime version (K-SADS-PL); 3. Are prescription stimulant-naïve, verified by the study doctor via SafeScript; 4. Are seeking mental healthcare; and 5. Can provide informed consent (sufficient English and adequate reading comprehension assessed; all participants will provide consent as will a carer or guardian). Exclusion Criteria: 1. Current or planned participation in another interventional study that would interfere with study participation in the opinion of the PI; 2. Prior recreational use of stimulants (e.g., MDMA, amphetamines) assessed with the ASSIST-Y and corroborated by urine toxicology and study doctor during medical examination; 3. Unstable medical conditions or contraindications for lisdexamfetamine including advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, glaucoma, phaeochromocytoma, tics and Tourette's syndrome, and history of seizures, assessed with medical exam, electrocardiogram, and clinical blood tests, and as assessed by the study doctor; 4. Current treatment with contraindicated psychotropic medications that cannot be safely discontinued as determined by the study doctor, including monoamine oxidase inhibitors; 5. Current or past DSM-5 psychotic or bipolar illness assessed with the K-SADS-PL; 6. Current DSM-5 stimulant use disorder, moderate or severe, assessed with the K-SADS-PL; 7. Acute suicidality or severe disturbance likely to interfere with the ability to comply with the study protocol as assessed by the study doctor with the C-SSRS; 8. Pregnancy, breast feeding or, if sexually active and of child-bearing capacity, no effective contraception as assessed by study doctor during the medical examination and corroborated by clinical blood tests (hCG).