IQ Estimate
The vocabulary and matrix reasoning subtests from the Wechsler Adult Intelligence Scale (WAIS_III) (Weschler 1997) were used to generate a short form IQ estimate (Sattler and Ryan 1999).
Psychosocial Functioning
The DSM-IV Global Assessment of Functioning scale (APA 1994) was used to assess psychosocial functioning.
Sexual Behavior
There are few widely used measures of sexual history and risk taking behavior with known reliability and validity. The following items were developed or adapted from those used by de Visser (2000): age at first sexual intercourse, history of HIV/STI testing, and lifetime frequency of condom use with casual partners, which was assessed using the following item: during your lifetime, how often have you used a condom during sexual intercourse with a casual partner? Responses were rated on a 4-point scale (1= never ; 4= always).
Psychological Distress
The Kessler 10 Psychological Distress Scale (Kessler et al. 2002), a brief 10 item questionnaire rated on a 5-point scale ( 1= none of the time; 5= all of the time), was used to measure the level of distress and severity associated with psychological symptoms. This scale has a stable factor structure (Brooks et al. 2006).
Self-esteem
The Rosenberg Self-Esteem Scale (Rosenberg and Pearlin 1978) was used to assess self-esteem. It contains 10 items rated on a 4-point scale ( 1= strongly disagree; 4= strongly agree). High scores indicate low self-esteem. Adequate test-retest reliability (r= 0.85 for 2 weeks) and convergent, discriminant, and predictive validity have been established (silbert and tippet 1965).