The purpose of this study is to develop the technology infrastructure for a mobile Web-based cognitive and neuropsychological assessment of substance abusers, and to perform a pilot trial using neurocognitive tasks designed to demonstrate that our system is statistically comparable to current clinical practice.

The primary hypotheses are that results collected using a web-based data collection platform will be comparable (but not necessarily equivalent) to data collected under controlled laboratory conditions, that methamphetamine (MA) dependent participants will have worsened neurocognitive performance compared to healthy volunteers, and the platform will be acceptable to participants.

Inclusion Criteria:

• Male or female, aged 18 to 55.
• Ability to give informed consent.

Exclusion Criteria:

• Unwilling or unable to access the web over a cell phone or living in an area with no cell phone service.
• Any medical, psychiatric, or other condition that, in the opinion of the investigator, would preclude safe, consistent, or useful participation in the study.