NEGATIVE ATTITUDE TOWARD SELF
The factor analysis of Beck Depression Inventory represents an important contribution because it recognizes the kind of symptoms that build the components of the depressive symptoms in a large sample of patients with narcolepsy. This was an exploratory factor analysis that offered a more precise definition of the relationship between items in one of the most used tests in the assessment of depressive symptoms on narcoleptics.
General discussion-136
The negative attitude towards self was the component that explained most of the symptoms of depression. Even though this is a component also found in patients with depression without narcolepsy, it is interesting because in patients with narcolepsy it is more manifest than in depressives without this sleep disorder. Yet, why do patients with narcolepsy report having a sense of failure, guilt, an expectation of punishment, self-hate and blame as the most important components of their depressive symptoms? It can be hypothesized that the attribution of the cause of the symptoms has been re-directed to themselves. Additionally, patients without cataplexy are informed at the time of diagnosis that cataplexy may turn up soon or later or maybe never. This can also be a source of anxiety and a false self-attribution of the causes of the beginning of cataplexy.
EARLY IDENTIFICATION OF DEPRESSIVE SYMPTOMS
Patients already diagnosed with narcolepsy, who report depressive symptoms should be screened for a major depressive disorder independent of the physical condition and not only focusing on the somatic dimension of depression but also on the cognitive one. Sleep specialists should be provided of basic training on identification of patients suffering from depressive disorders. Early identification of depressive symptoms means more effective treatment not only for depression but also for narcolepsy. Furthermore, sleep specialists should be more aware of the importance of engaging family and peers of patients (also adults) during treatment. The emphasis is on patients with an onset in adulthood probably because when the onset is during childhood, familial support is greater. The family of patients with depressive symptoms could help to develop coping strategies more easily, which could increase the chance of a chronically ill patient’s integration in society. Furthermore, failure in school or in the workplace together with obesity and the fear of not being understood are situations that every patient with daytime sleepiness struggles with throughout life.
6.4.7. Limitations of the dissertation
SAMPLE AND METHODS
The presence of depressive symptoms or suspicion of a psychiatric condition in the clinical interview carried out in the sleep center was an exclusion criterion for the IH patients. There is a dilemma on this topic because patients who have depressive symptoms because of the IH symptoms will have fewer possibilities of being diagnosed due to these ICSD-2 criteria (Billiard & Dauvilliers, 2001b). Therefore, possibly two things occur: the first is that some real patients were excluded following this criterion and the second is that as a
consequence, a bias on this group has been unintentionally generated. During this study, it was possible to have contact with the patients, some of whom were very engaged in the organization of the meetings, even when they reported high scores in depression questionnaires. This seemed very contradictory but was in line with the finding of the second study that shows that narcoleptics with depressive symptoms are more interested in participating in activities, which produce satisfaction than non narcoleptic patients with a similar level of depression but are non narcoleptic. The type of depression in narcoleptic patients is, in summary, best described as an atypical depression.
While one advantage of the present study was the matching of patients in order to have a similar level of depression, some limitations were encountered such as not having exact data on the dosage of antidepressants. This dosage was possibly higher in patients with depression.
6.4.8. Future research directions
One of the results of this dissertation shows that narcoleptic patients with depressive symptoms are more hedonistic than patients with depression. This does not state that narcolepsy patients with depressive symptoms maintain a normal hedonic level. Rather, the results are evidence of a significant difference in comparison with depressed patients in spite of the same level of depression. This outcome is interesting because anhedonia is a cardinal symptom of major depression and the experience of enjoyment is the typical trigger of a cataplexy episode. Therefore, it is possible to hypothesize that narcolepsy patients with cataplexy are in some way protected from the symptom of anhedonia. Looking at this point from a different perspective, it appears that patients who maintain a good level hedonic experience are more prone to experience cataplexy, because they expose themselves to more emotional stimuli. Meehl suggested that there is a normal- range of individual differences in the hedonic capacity in the general population and a reduced capacity to feel pleasure in non-clinical individuals may be associated with brain abnormalities that constitute neural markers of vulnerability for some psychiatric disorders (Meehl, 2001). A possible future research question would be to identify the brain regions whose activity during the processing of hedonic information varies in function of anhedonia severity in control subjects and narcolepsy patients. So far, functional neuroimaging studies of anhedonia have focused exclusively on two clinical populations, either schizophrenia or MDD (Harvey, Armony, Malla & Lepage, 2010). It is not yet known if narcolepsy patients differ from controls in the range of hedonic levels.
General discussion-138
The possibility that narcoleptic patients with a depression are prone to an atypical depression is an interesting likelihood which needs further confirmation. An exploration of this topic should re-test this result and corroborate the presence of other symptoms of atypical depression such as subjective personal rejection by others.