- Master Hypnotist and Hypnotherapist (Omni Institute, Fla. Atlantic University, USA, 1990).
- Regression therapist (Dr Brian Weiss, U. Miami, 1990)
- Death and Dying therapist (Kubler-Ross, Denver, 1990)
- Certified Hospice Trainer (Palm Beach, Fl., 1989)
- NLP Practitioner (ABNLP-certified, 2005)
- Time-Line Therapy (Performance Unlimited, UK, 2005)
- High Performance Coach (Performance Unlimited, UK, 2005)
"During his years in the USA, he was highly active in the original activist movement to demand treatment and research for those living with HIV, and assisted in setting up numerous programs and agencies, for which he received a Presidential Acknowledgment in 1994, from President Clinton.
"His longevity and health have been intensively studied by all the top AIDS research institutions in the USA, including the National Institute of Health, and the discoverers of HIV, Robert Gallo, Luc Montagnier, and Jay Levy. Participated for six months in 1986 in the original human trials for AZT. Did not require antiretrovirals until December 2004, when his CD4 count dropped to 350. Currently (April 2009) his CD4 count is 1224, and has an undetectable viral load.
"David has also been part of several studies of so-called ‘long-term non-progressor’ studies that are trying to find the common factors in a group of people who have managed to maintain immune function despite 20 years or more of being infected with HIV. The findings of these studies of long-term non-progressors are the basis for the book Positive Health.
"David has appeared on many television and radio shows, as an advocate for people living with HIV, specifically to encourage infected people to take control of their own health, versus assuming a victim role.
"Along with Neil Orr, he has co-authored The Healer Inside You (Juta Press), which describes how PNI can be applied for self-healing. Other co-authored books include: Sex Secrets (life skills for teenagers); Choices; and Positive Health (5th Edition)." 
- Neil Orr and David Patient, Positive Health (6th edition, Jacana Media 2007).
- Neil Orr and David Patient, The Healer Inside You: Using PNI, a Mind-body Science, to Help Heal Your Body (Juta and Company Ltd, 2004) - developed a so-called healing programme based on psychoneuroimmunolgy - "Forms the basis for the support group therapy protocol entrained to, and utilised by UNDP, UN GIPA, Shell, Tsogo Sun Holdings."