A Double Blind Crossover Study on the Effect of MPH on Decision-making Ability of Adults With BPD Compared to Adults With ADHD and Healthy Adults

• Test of Variables of Attention (TOVA) score [ Time Frame: 20 minutes ] [ Designated as safety issue: No ]

  This test, devised by Greenberg and Kindschi (1996), is one of many continuous performance tests (CPTs), rapid reaction-time tasks in which participants have to discriminate predetermined target stimuli from distracting non-targets. CPTs, and TOVA among them, are widely used both by practitioners and investigators as an objective tool for assessing ADHD and determining beneficial medical effects (Llorente et al. 2001).

  The TOVA used here is a standardized, fixed-interval (21.6 ± 1.1 min), visual CPT.

  
  
• Iowa gambling task (IGT) score [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  a computerized version of the Iowa Gambling Task (Bechara et al. 1994), which assesses reward learning. In this task the participant is presented with four decks of cards on the computer screen. Each card yields a reward, but might also cast a loss. In each trial, the participant selects a card out of one of the four decks by clicking on it. Consequently, the card is exposed, displaying the gain and the loss for that trial. The accumulated total amount is presented at the bottom of the screen all along, and is updated after every trial. Through contingent feedback, participants are expected to learn that decks A and B yield constant large gains but also larger losses, so that their net loss across trials is 2,500 tokens, whereas decks C and D yield smaller gains but also smaller losses, leading to a net gain across trials of 2,500 tokens
  
  
• Foregone Payoff Gambling Task (FPGT) score [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  gambling task is a version of the IGT developed for the purpose of the current study. Two differences distinguish it from the original version - a different payoff distribution as detailed in Table 3, and a feedback method called foregone payoffs: following each choice made by the participants, they get to see not only the card chosen but also the other three cards from the three decks not chosen. This provides more information, but can also cause temptation, and may distract participants from the advantageous decks (see e.g., Yechiam et al. 2005; Yechiam and Busemeyer 2006).
  
  
• Spatial Working Memory (SWM) score [ Time Frame: 10 minutes ] [ Designated as safety issue: No ]
  CANTAB task for assessing Spatial Working Memory
  
  
• digit span score [ Time Frame: 20 minutes ] [ Designated as safety issue: No ]
  Forward and Backward digit-span task (Wechsler 1981)
  
  

Participants will be required to arrive at the cognitive laboratory in "Shalvata" for two visits: the first visit will include obtaining informed consent, screening (as detailed below), and performing a battery of computerized tasks. The second visit will include performing of the same battery of tasks, and payment.

In one of the visits, participants will receive a capsule containing Methylphenidate or placebo (MPH; Ritalin) (dosage: 10 mg in case weight<40 kg; 30 mg in case weight>90 kg; otherwise 20 mg -( The pills will be 10mg each, and the number of pills will be administered according to the dosage stated; 1-3 pills, according to weight). Prior to performing the tasks, and in the other visit they will receive a capsule containing placebo.