The investigators will examine the acute effects of stimulant medication on executive functioning. The rationale for the proposed study is to examine the efficacy of stimulants for college students with ADHD and help prevent stimulant misuse among college students without ADHD. The working hypothesis is that stimulants, compared to baseline and placebo conditions, will improve executive functioning for college students with ADHD but not for college students without ADHD. Improvements on executive functioning measures (e.g., CPT-IP, Spatial Span) will be examined through 2 (ADHD vs. non-ADHD) x 3 (Baseline, Placebo, Stimulant) repeated measures ANOVAs. Follow-up analyses will include paired comparisons.
Expected outcomes are to confirm these hypotheses and demonstrate the need for further study of stimulants. If confirmed, the results will provide pilot data for a larger NIH grant proposal aimed at further examining the acute effects of stimulants (i.e., improved cognitive functioning with stimulants) and comparing them to the acute effects of physical exercise (i.e., improved cognitive functioning immediately after exercise). The investigators expect this outcome to have an important positive impact because it can help support stimulant medication as an effective treatment for college students with ADHD (DuPaul et al., 2012). Additionally, demonstration that stimulants do not improve executive functioning for college students without ADHD can be used to help prevent and discourage stimulant misuse and diversion on college campuses (Hartung et al., 2013).
Be currently enrolled either full time or part time as an undergraduate in a 2-year or 4-year college
Be between the ages of 18-29
Be a native English speaker
ADHD Participants: Must report a prior diagnosis of ADHD and self-report five or more inattention (IA) symptoms on the DSM-5 Symptom Checklist on the pre-screener.
Not meeting any of the above stated inclusion criteria
Participants will be excluded if they report having an acute or uncontrolled disease (cardiovascular, pulmonary, neurological, endocrine, musculoskeletal, immunological).
Participants will be excluded if they are non-ambulatory or rely on walking aids for ambulation.
Participants will be excluded who chronically manage asthma or another respiratory condition or require using an inhaler to complete exercise.
Single group
Adderall IR 10mg
DrugAt one of the experimental appointments, participants will be administered a stimulant medication. Following a wait period, the participants will complete executive functioning tasks of working memory and sustained attention.
Placebo
DrugPlacebo
Change in Continuous Performance Test - Identical Pairs (CPT-IP) for Adderall vs. Placebo
The CPT-IP is a standardized computer-administered test consisting of four-digit numbers that are presented for 200ms on a white screen with 1500ms between the presentation of each number. Participants must press the spacebar as quickly as possible when the preceding four-digit number matches the current four-digit number. Participants will complete the CPT-IP as a measure of sustained attention at baseline and at each experimental appointment.
Change in Spatial Span (SS) for Adderall vs. Placebo
The Spatial Span (SS) is a computer-administered task assessing visuospatial working memory. Participants will be tasked with remembering the order of stimuli that are presented in forward and backward sequences. Participants will complete the SS visuospatial working memory task at baseline and at each experimental appointment.
Change in Digit Span for Adderall vs. Placebo
The Digit Span (Wechsler, 2008) subtest of the Wechsler Adult Intelligence Scale (WAIS-IV) is an auditory working memory task. The researcher will say numbers aloud at a rate of one number per second. The participant will be tasked with remembering and repeating the numbers in a prescribed (forward, backward, sequencing) order. Participants will complete the Digit Span (forward, backward and sequencing) auditory working memory task at baseline and at each experimental appointment.
Change in Letter-Number Sequencing for Adderall vs. Placebo
The Letter-Number Sequencing (Wechsler, 2008) task is a supplemental subtest of the Wechsler Adult Intelligence Scale (WAIS-IV) that measures auditory working memory. Researchers will read a sequence of letters and numbers, and the participant will attempt to recall the numbers in ascending order and the letters in alphabetical order. Participants will complete the Letter-Number Sequencing auditory working memory task at baseline and at each experimental appointment.
Pittsburgh Sleep Quality Index-Modified (PSQI-M)
The PSQI contains 19 items that evaluates several components of sleep quality by requiring participants to report their sleep behaviors. Participants will receive the survey via text and email the morning after their experimental appointment. They will be instructed to complete the PSQI-M regarding their sleep functioning (i.e., subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbance, use of sleep medication, and daytime dysfunction) from "yesterday (from the time after your lab appointment until you went to bed)."
Depression, Anxiety, and Stress Scale-Modified (DASS-M)
This scale includes 21 questions to measure current mood and stress levels. Items include a choice of four responses from "Did not apply to me at all," to "Applied to me very much." Participants will receive the survey via text and email the morning after their experimental appointment. They will be instructed to complete the DASS-M regarding their emotional experiences of depression, anxiety, and stress from "yesterday (from the time after your lab appointment until you went to bed)."
DSM-5 ADHD Symptoms Checklist - Modified (DSM 5-M)
The DSM 5-M will ask participants about how often they experienced the symptoms of ADHD for the 24 hours from "yesterday (from the time after your lab appointment until you went to bed)" and will be completed following both experimental sessions
Side Effects Rating Scale - Modified
The Side Effects Rating Scale - Modified asks participants about behaviors from side effects of ADHD medication for the 24 hours from "yesterday (from the time after your lab appointment until you went to bed)" and will be completed following both experimental sessions
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