48 39. Certain incidents that have occurred during deportation operations have highlighted the importance of allowing immigration detainees to undergo a medical examination before the decision to deport them is implemented. This precaution is particularly necessary when the use of force and/or special measures is envisaged. Similarly, all persons who have been the subject of an abortive deportation operation must undergo a medical examination as soon as they are returned to detention (whether in a police station, a prison or a holding facility specially designed for foreigners). In this way it will be possible to verify the state of health of the person concerned and, if necessary, establish a certificate attesting to any injuries. Such a measure could also protect escort staff against unfounded allegations. 40. During many visits, the CPT has heard allegations that immigration detainees had been injected with medication having a tranquillising or sedative effect, in order to ensure that their deportation proceeded without difficulty. On the other hand, it also noted in certain countries that instructions prohibited the administration, against the will of the person concerned, of tranquillisers or other medication designed to bring him or her under control. The CPT considers that the administration of medication to persons subject to a deportation order must always be carried out on the basis of a medical decision taken in respect of each particular case. Save for clearly and strictly defined exceptional circumstances, medication should only be administered with the informed consent of the person concerned. 41. Operations involving the deportation of immigration detainees must be preceded by measures to help the persons concerned organise their return, particularly on the family, work and psychological fronts. It is essential that immigration detainees be informed sufficiently far in advance of their prospective deportation, so that they can begin to come to terms with the situation psychologically and are able to inform the people they need to let know and to retrieve their personal belongings. The CPT has observed that a constant threat of forcible deportation hanging over detainees who have received no prior information about the date of their deportation can bring about a condition of anxiety that comes to a head during deportation and may often turn into a violent agitated state. In this connection, the CPT has noted that, in some of the countries visited, there was a psycho-social service attached to the units responsible for deportation operations, staffed by psychologists and social workers who were responsible, in particular, for preparing immigration detainees for their deportation (through ongoing dialogue, contacts with the family in the country of destination, etc.). Needless to say, the CPT welcomes these initiatives and invites those States which have not already done so to set up such services.