• Attention Deficit Hyperactivity Disorder (ADHD) Rating Scale-IV-Parent Version: Investigator Scored Total Score at 12 Weeks [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  Measures the 18 symptoms contained in the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision (DSM-IV-TR) diagnosis of Attention-Deficit/Hyperactivity Disorder. Individual item scores range from 0 (none/never or rarely) to 3 (severe/very often). Total scores range from 0 to 54. Higher scores indicate greater impairment. The scale is scored by an investigator while interviewing the parent.
  
  

• Clinical Global Impression-ADHD-Improvement (CGI-ADHD-I) at 12 Weeks [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  Measures total improvement (or worsening) of a patient's ADHD symptoms from the beginning of treatment. (1=very much improved, 7=very much worsened)
  
  
• Change From Baseline to 12 Weeks in Global Impression of Perceived Difficulties (GIPD) - Participant Rated Version [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  The Global Impression of Perceived Difficulties (GIPD) scale is a five-item rating of ADHD-related difficulties. For each item, difficulties during the past week are rated on a 7 point scale (1=normal, not difficult at all; 7= extremely difficult). The GIPD total score is the sum of all subscores (items) and ranges from 5 to 35. Higher scores indicate greater impairment. The scale is completed by the participant.
  
  
• Change From Baseline to 12 Weeks in the Children's Depression Rating Scale-Revised (CDRS-R) [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  Measures presence and severity of depression. Consists of 17 items scored on a 1-5 or 1-7 scale (1 = no symptom difficulties; 5 or 7 = severe clinically significant difficulties) A rating of 1 indicates normal, thus the minimum score is 17. The maximum score is 113. In general, scores below 20 indicate an absence of depression; scores of 20 or 30 indicate borderline depression; scores of 40 to 60 indicate moderate depression.
  
  
• Change From Baseline to 12 Weeks in the Pediatric Anxiety Rating Scale (PARS) [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  The Pediatric Anxiety Rating Scale (PARS) is used to rate the severity of anxiety in children and adolescents, ages 6 to 17 years. The total score for the PARS is derived by summing 5 of the 7 severity/impairment/interference items (2,3,5,6,7). The total score ranges from 0 (none) to 25 (extreme severity). Items 1 (overall number of anxiety symptoms) and 4 (overall severity of physical symptoms) are not included in the total score calculation.
  
  
• Change From Baseline to 12 Weeks in the Marijuana Craving Questionnaire (MCQ) [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  The MCQ is a 12-item self-rated questionnaire to assess cannabis craving with 4 factors: compulsivity (an inability to control marijuana use), emotionality (use of marijuana in anticipation of relief from withdrawal/negative mood), expectancy (anticipation of positive outcomes from smoking marijuana) and purposefulness (intention and planning to use marijuana for positive outcomes). Scores are calculated on a 7-point scale (1=strongly disagree; 7=strongly agree). A separate score is calculated for each factor; scores range from 3-21 each with higher scores indicating greater craving.
  
  
• Change From Baseline in Neurocognitive Functioning as Measured at 12 Weeks by a Test Battery: Stop-Signal Task [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  Consists of 2 types of trials: go trials and stop trials. Go trials require participants to locate the position of an aircraft displayed to the left or right of a fixation point on a computer screen by pressing a left or right button. In 25% of the go stimili an additional stop stimulus (auditory signal) is presented shortly after the go stimulus. Participant then needs to inhibit their response. By varying the time period between go and stop stimulus, 50% of the trials are inhibited successfully, 50% not. The latency of inhibition is estimated. This task takes about 25 minutes.
  
  
• Change From Baseline in Neurocognitive Functioning as Measured at 12 Weeks by a Test Battery: Contingency Task [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  For the Contingency Task participants estimate the duration of a time interval of 1 second by pushing a button. Responses that are within a dynamic time interval are being classified as correct. This way, 50 % of the responses are correct, 50% incorrect. Three contingency conditions: neutral, reward and response cost. The performance of this task takes about 15 minutes.
  
  
• Change From Baseline in Neurocognitive Functioning as Measured at 12 Weeks by a Test Battery: Time Reproduction Task [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]
  For the Time Reproduction Task participants need to reproduce the duration of a visual stimulus (lightbulb) by pressing a button. The intervals vary between 2 - 20 seconds. The performance of this task takes about 15 minutes.
  
  
• C-SSRS Suicidal Ideation By Visit at Week 4: Non-Specific Active Suicidal Thoughts [ Time Frame: Week 4 ] [ Designated as safety issue: Yes ]
  Solicits suicide-related information with structured questioning. Scale consists of 28 items in 4 sections: suicide behavior, actual attempts, suicidal ideation, intensity of ideation. Suicidal ideation consists of 5 yes/no items: wish to be dead, non-specific active suicidal thoughts, active suicidal ideation with any methods (not plan) without intention to act, active suicidal ideation with some intent to act without specific plan, active suicidal ideation with specific plan and intent. Only items with yes responses at a given week are listed.
  
  
• C-SSRS Intensity of Ideation (Most Common Ideation Type and Most Severe Ideation Type) By Visit at Week 4 [ Time Frame: Week 4 ] [ Designated as safety issue: Yes ]
  Participants rate most common and most severe ideation type by frequency (1=<once per week/5=many times/day), duration (1=fleeting/5=>8 times per hour persistent, continuous), controllability (1=easily able to control thoughts/8=no attempt), deterrents to active attempts (1=deterrent definitely stopped you/8=N/A, wish to die only), and reason for ideation (1=completely for attention/revenge/reaction/5=completely to stop the pain). Only items with yes responses at a given week are listed. A participant could have a yes response in more than one item.
  
  

In the past adolescents with cannabis abuse have been excluded from studies in which atomoxetine for ADHD symptoms was studied. In this study the efficacy of atomoxetine on symptoms of ADHD in adolescents with ADHD and comorbid cannabis abuse will be studied.