A critical aspect of real-world functioning following kidney transplantation involves how adherent individuals are to their medication regimens. Regardless of the possible dangers of failing to adhere to anti-rejection medications, such as increased graft rejection, studies have reported rates of non-adherence at almost 50% following renal transplant.

The Cognitive Aging Laboratory under the direction of Dr. Wendy Thornton, at Simon Fraser University, has previously identified relationships between several potentially important cognitive and psychosocial variables, and self-reported medication adherence in renal transplant recipients, including depressive symptoms, as well as everyday and traditional cognitive functioning [4]. The possibility that changes in dosing regimens for a given medication may have an additional impact on medication adherence presents an important issue worth further exploration.

The current study will allow for more thorough delineation of the roles of psychosocial and cognitive predictors of adherence with state-of-the-art monitoring techniques. In addition, the investigators will assess whether different dosing formulations of tacrolimus impact adherence behaviors in renal transplant recipients.

The proposed research has two primary aims to examine:

1. To examine the role of cognitive and psychosocial variables in predicting medication adherence in renal transplant recipients.
2. To examine whether different formulations of tacrolimus (once per day dosing versus twice per day dosing) will impact medication adherence in renal transplant recipients.

Inclusion Criteria:

• a minimum of one year post renal transplant with a successful kidney graft and stable renal function (estimated glomerular filtration rate [GFR (glomerular filtration rate)] above 25 ml/minute per 1.73 m2).
• currently prescribed tacrolimus
• able to swallow pills
• a minimum of grade six education
• fluent in the English language.

Exclusion Criteria:

• refusal to or inability to give written informed consent.
• any visual, hearing or other sensory/motor impairments which may interfere with the testing procedures.
• have had a stroke determined to be of significant severity
• have had a head injury determined to be of significant severity
• have a current psychiatric diagnosis determined to be of significant severity
• have the presence of an acute illness (e.g., metastatic cancer), neurological disease, and other major organ failure (e.g., end stage liver disease)