Crystal meth use can exhaust your immune system, due to decreased appetite, poor eating habits and weight loss.  Meth simultaneously speeds up the rate of HIV replication in your body and reduces the effectiveness of HIV medications.  Some HIV medications can cause the body to absorb meth at a much quicker rate, which can lead to severe reactions or a possible drug overdose.  Being high on crystal meth may lead you to forget to take your HIV medications or stay on your treatment schedule, both of which can lead to HIV medication resistance.

Both HIV and crystal meth drug use can also cause depression, altered cognitive functioning, memory problems and sleep disorders. Naturally, if one is HIV-positive there should be the concern of developing cognitive problems down the road. There is some rationale to worry that abusing crystal may predispose an HIV-positive person for further memory problems, or more importantly, overt dementia. However, it may be too early for us to know since little research has been done in this area.

Additionally, depression has been a common problem that many HIV and AIDS patients endure during their infection course. Prolonged use with crystal methamphetamine is associated with withdrawal symptoms that occur 24 hours after usage, most commonly severe depression, fatigue and even suicidal thoughts. This, compounded with an underlying depression related to HIV disease, can result in more complexities related to psychological and psychiatric effects. Moreover, a study published in the Journal of Neuropsychiatry and Clinical Neurosciences (2000: 12; 480-4) demonstrated long-term chronic depression with crystal use. Other studies also documented that the majority of patients who have completed treatment for crystal methamphetamine abuse are dealing with depressive problems long after. Thus patients who become chronic users of crystal may have to deal with long-term psychological and psychiatric effects.¹

¹ Berger, Daniel S, Crystal Methamphetamine and HIV -- A Catastrophe. Positively Aware 2004 Jul/Aug; 44.