Peter (51 years old, married with 2 teenage daughters) started working at the age of 14. He was “not fit for school, more of a practical guy”, worked as a hired help at a transportation company, and at age 21 got a commercial driver’s licence. Since then, he has been employed as a truck driver. He enjoyed his work on long haul projects, driving bulk-goods from Rotterdam harbour to all parts of Europe. Being a truck driver, he stuck to his bosses rule of “a beer or two max a day”, during his long weeks from home. During the occasional week off at home, he tended to drink somewhat more. During this time he could increasingly more often be found in the pub. At one point his company underwent reorganization and Peter was assigned to parcel delivery service. To plan his deliveries all over the Netherlands, Peter had to work with an electronic route manager. In the new situation he had to work a tight schedule. This was too much for Peter: he encountered numerous problems with the device, ran late and got more, and more frustrated and annoyed (as did his customers). After 2 weeks of trying to fulfil his new assignment, he went on sick leave. Bored at home, he spent more and more time in the pub, drinking until the point of obliviousness. When he had to visit the doctor to get a sick note, he was referred to a counsellor because of his drinking. During the intake, it became clear that Peter struggled to adapt not only to his new working conditions, but also to his role in his family, now that he spent more time at home. Drinking seemed Peters “solution” to ease his anxiety and stress. Peter was referred for psychological evaluation, during which it became clear that Peter could neither read nor write. He tested in the mild to borderline IQ range, with a verbal IQ of 74, and a performance IQ of 69. Only after this test did Peter reveal that as a child, he attended a “school for retarded children”.

As the case of Peter illustrates, it may not immediately become clear during treatment that a person has MID. Though many persons with MID can benefit from social services for those with ID (such as sheltered living, sheltered working, or community-based services), a large majority (especially those with borderline ID) does not receive specialized help. In fact, many individuals with MID do not see themselves as being “handicapped” and may therefore refuse specialized services themselves. Others may have had some specialized care in the past, but then terminated the service, often because of a need of more autonomy and independence. Most countries currently have policies that encourage more inclusive societal or community-based care. This allows many people with MID to live a “normal” life, albeit with a little help. Thus, the fact that a patient holds a job or lives with a family of his own, does not preclude him from having an MID.

In many European countries, changes in health-care systems have led to a greater degree of deinstitutionalisation and integration of people with MID in the community. It could be that these changes lead to an increased vulnerability of substance abuse among people with MID. However, substance use and abuse is common in all subgroups of MID, including those in residential care (VanDerNagel et al. 2011a). The use of psychoactive substances (other than prescribed drugs) may in itself be a problem for ID settings, as some institutions have regulations against using substances. Other settings allow use of (some) substances, mostly limited to alcohol and tobacco, provided that staff members and other patients are not confronted with excessive use or negative consequences. Although these rules may provide support for some patients to stay clear of substance use, others might not be deterred. In ID services that ban (all or some) substance use, the substance use may go underground, or clients might use within their own quarters or outside the facility, and refrain from asking help when substance use poses problems. Several ID-facilities across Europe recognize this risk, and have started programmes to promote early identification and—if needed—adequate referral to substance treatment facilities. For instance, several ID facilities in the Netherlands and Flanders have implemented the use of the SUMID-Q, a Dutch instrument used to screen for and assess substance use (risk) among patients with ID (see Sect. 15.4). Unfortunately, such programmes are not widely implemented yet.

Co-occurring psychiatric problems are an additional risk factor for substance abuse among people with MID. At the European level, little is known about prevalence rates of MID substance users with co-morbid psychiatric problems. In a Dutch sample of 185 MID individuals admitted to substance abuse treatment facilities, 42 % had a co-occurring behavioural or emotional problem (Didden et al. 2009). In a sample of 115 MID adults seeking mental health services in London, 8 % were current substance abusers and 15 % had a history of substance abuse (Chaplin et al. 2011). These numbers suggest a need to incorporate the comprehensive assessment of substance abuse and psychiatric disorders into treatment plans for people with MID in mental health or psychiatric settings. Not in the least because triple diagnosis is often combined with problems in other areas such as housing, work, and social relationships.

The assessment of co-occurring psychiatric problems in those with MID and substance use disorder poses additional challenges to mental health care professionals for a variety of reasons. First, it requires knowledge of three fields of (mental) health care (addiction, general psychiatry and ID care). Though several countries (e.g. the UK) have excellent mental health services for those with MID, these services often do not include addiction services. Second, there is a lack of appropriate diagnostic instruments and assessment methods for psychiatric conditions among those with MID. Third, psychiatric conditions may present differently among those with MID, and especially when there is co-occurring substance abuse.

Claire is a 21 years young woman with trisomy 21 (Down’s syndrome). At the age of 18 she moved to a community-based training house, to learn skills needed to live on her own. Shortly after this move, she experienced a depressive episode. This was attributed to the changes in lifestyle and demands associated with these changes and successfully treated with cognitive behavioural therapy in combination with temazepam prescribed by her GP because of her sleeping problems. After this major episode, Claire has generally been doing well. With some help of the ID service staff, she started working as an aid at a food court. Here she enjoyed serving customers and meeting new people. In the last year or so, she started to “hang out” with some of the local youth after work. After a while, she even joined this group on Friday night outings. At first the staff members applauded this, since making friends had always been difficult for Claire. However, after six months, there were some concerns. Claire was late in returning to the house several times and disregarded house rules regarding alcohol use and smoking. She also started talking rudely to the staff, claiming that she “was entitled to make her own choices”. Even more concerns arose when Claire asked her older sister if she had ever tried ecstasy pills or speed. Fortunately, Claire also remained interested in improving her adaptive skills. Although she was always a bit anxious about living on her own, she seemed to consider this to be a serious option in the last few months. She even planned to get her drivers’ licence, which appeared impossible, as Claire has difficulties negotiating busy traffic even when on foot. One Saturday, things went wrong. Claire, who had been partying the night before, was irritated by the sounds of her housemates and picked a fight. She ended up assaulting a staff member who tried to intervene, and kept yelling that she was to make her own choices. Even her parents were unable to calm her down. Even though the yelling stopped, Claire stayed restless, very talkative, and full of plans of how she wanted to change her life by moving out instantaneously, getting a better paid job and finding someone to start a family of her own. Nobody slept well that night, including Claire, who kept packing and unpacking her suitcase. The next day, Claire agreed to talk to a person of specialized mental health services, and eventually was admitted with a tentative diagnosis of “drug induced psychosis or mood disorder”. Only when her irritability, grandiose and racing thoughts, sleeplessness, and restlessness did not subside after several weeks, did she receive the diagnosis of Bipolar I disorder.