This research shows that patients with psychotic disorders frequently contact their GPs. In particular, the age group 16 - 65 years receives a lot of care in comparison to the control groups: there are more consultations at the office, GPs pay them more visits, and have more telephone contacts. As people become older, the percentage of organic psychoses increases to more than fifty percent. Mental confusion and hallucinations in the elderly, whose brains are more vulnerable, are often caused by physical disorders [
23]. As a consequence, the elderly have a different spectrum of psychotic disorders than younger adults or adolescents. Organic psychosis dominates in this age group, and accordingly these patients receive more home visits from their GPs.
A minority (7.6%) of the patients of the group with psychotic disorders have been registered with different diagnostic labels during the five registration years. A diagnosis of 'non-specific psychosis' (code P98) can typically change into 'schizophrenia' (P72) or 'affective psychosis' (P73). On occasion, the difference between these diagnoses is unclear.
Chronic diseases, notably diabetes mellitus, cardiovascular diseases and chronic lung diseases, are frequent in patients with psychotic disorders, although in this research the incidence of these chronic diseases in adults with psychotic disorders does not differ significantly from the other groups. This deviating finding could be an effect of the sample group, which contained a wide variety of psychotic disorders. There might also be cases of underdiagnosis, which is in keeping with the results of other research [
20], because the recognition of the high risk of these chronic diseases in patients with psychotic disorders is rather new for GPs. In addition to underdiagnosis, a further problem in relation to these conditions is undertreatment [
20,
21,
24]. However, in this Dutch study the number of contacts made by the GP, related to diabetes mellitus, is similar for the psychosis group and the control groups.
A small number of patients with diabetes mellitus is referred to an internist. This number is almost equal for both groups with mental health problems. On the other hand, psychosis patients are referred more often to an eye doctor or a podiatrist. An explanation could be that the treatment targets were not met by the GP as a consequence of non-compliance in these patients. The high number of referrals to the eye doctor could also be biased by the occurrence of other eye diseases, because patients with schizophrenia attend visual examinations less frequently than others, and their vision is notably weaker [
25]. Finally, these patients might be more severely ill because they contact their GP at a later stage of the disease [
17-
19].
With respect to cardiovascular diseases, the average number of GP contacts per episode for patients aged 16 to 65 inclusive also appears to be the same as for the control groups, although elderly psychosis patients are seen far less frequently for cardiovascular checks. We presume that the GP's care for these elderly patients focuses more on the quality of life than on diagnosing and treating risk factors for cardiovascular diseases. Also, the cardiovascular patients with psychotic disorders are referred to secondary care more often. These patients suffer from more additional risk factors such as obesity, diabetes mellitus and smoking addictions [
26,
27], which might make them more severely ill.
Among elderly psychosis patients, both the number of episodes and the number of follow-up contacts appears to be lower with respect to chronic lung diseases. A possible explanation for these findings could be that there is some kind of selection due to the early death of schizophrenia patients [
28,
29].
GPs aim to meet the demands of the patient. However, providing care to patients with psychotic disorders is complicated. These patients find it difficult to carry out the doctor's lifestyle advice and their adherence to prescribed treatment is low. There are often severe psychosocial problems, requiring their attention and inhibiting life style changes. On the other hand, these patients do use the primary care very frequently, and are often satisfied with the amount and type of service provided for their physical needs [
30]. Considering the high contact frequency, the GP gets ample opportunities to perform regular health checks. One can assume that active screening for diabetes mellitus, cardiovascular diseases, and obstructive lung diseases in these patients will lead to more diagnoses. Starting treatment and coaching at an earlier stage could delay the progress of the illnesses [
31].
Since the study period (2002-2007), primary care for chronic diseases, such as diabetes mellitus, cardiovascular diseases, and chronic pulmonary diseases, has developed into programmatic care, through which patients are contacted by a practice nurse and undergo a physical and laboratory check. A great deal of time and attention is spent on education, counselling, and improving self-management. Patients with psychotic disorders also deserve this type of care.
It is clear that the division between mental health care and primary care hinders the provision of effective, coherent care. Therefore, the European Psychiatric Association (EPA) and the World Psychiatric Association (WPA) have stated that collaboration and communication between GPs and psychiatric services should be promoted [
32,
33]. Coordination between all care providers within the family practice and with specialist services is essential for optimal patient care.
Strong and weak points
The LINH database has supplied longitudinal data about morbidity and the use of care in Dutch general practitioner practices. The index group of 'Psychotic disorders' covers the entire range of psychotic disorders in the general practitioner coding system (ICPC).
Comparing patients suffering from psychotic disorders with both patients suffering from other mental health disorders and patients without mental health problems has produced a clear picture of the type of care provided to psychotic patients. This research only involved those patients whose psychotic disorder had been registered in the electronic medical record by the general practitioner and who had visited their general practitioner in 2002. This means that all patients whose psychosis had not been recognized and registered, as well as those who had not visited their general practitioner in 2002, were excluded from this research.