Detention can be particularly damaging to vulnerable categories of migrants, including victims of torture, unaccompanied older persons, persons with a mental or physical disability, and persons living with HIV/AIDS. The UNHCR guidelines provide that, given the very negative effects of detention on the psychological well-being of those detained, active consideration of possible alternatives should precede any order to detain asylum-seekers belonging to vulnerable categories. The Special Rapporteur is of the opinion that the same principle should apply to vulnerable migrants. In the event that individuals falling within these categories are detained, it is advisable that this should only be on the certification of a qualified medical practitioner that detention will not adversely affect their health and well-being. In addition, there must be regular follow up and support by skilled personnel. They must also have access to adequate health services, medication and counselling.