This study demonstrated that it is possible to identify 2 subgroups of monopositively symptomatic FEP patients from a longitudinal symptom perspective. We found that the patients with a clinical picture dominated by hallucinations were of a younger age and had completed fewer years of education. This contrasted with results from a previous study by Mauri et al. [11
], who found the group of patients dominated by hallucinations to be older at the time of onset and with higher academic achievement. On the other hand our findings are similar to previously mentioned studies of nonclinical voice hearers that reported the group experiencing hallucinations to be younger at the age of onset compared to a schizophrenia patient group [9
]. The main reason for the divergent findings is likely because different patient populations were involved, i.e. Mauri et al. [11
] examined patients with chronic psychosis, whereas our patients were in their first episode.
We additionally found that the H group scored poorer on both social and academic premorbid variables. To our knowledge no other study has examined this relationship, or found this difference that appears to be present even before the onset of psychosis.
The most notable finding of this study is the apparent relationship between symptomatology and suicidality. The difference in suicidality between the 2 groups was statistically significant at baseline but appeared to level out at later times. This could be due to attrition of the most highly suicidal patients in the H group, where 25% of the patients were deceased at the 5-year follow-up. This contrasts with the D group, where the mortality rate was much lower (1 fifth), and fewer patients were lost to suicide.
It may be that the increased suicidality in the H group could be related to the clinical picture itself, insofar as hallucinations tend to be experienced as frightening, intrusive and imperative, and might lead to suicidal thoughts and acts more easily. A recent review of schizophrenia and suicidality reported on 5 empirical studies of command hallucinations and their relationship to suicidality [30
]. The results were conflicting, with 3 of the studies finding that command hallucinations did not correlate significantly with suicidal ideation and attempts.
Our data indicate that suicidality is more tightly linked to hallucinations than delusions. A potential mediator between hallucinations and suicidality could be insight. A substantial body of data supports insight as a risk factor for suicidality in schizophrenia[31
]. As previously mentioned by Mauri et al. [10
], better insight might be linked with hallucinations. More recently a study found that patients with hallucinations without concurrent delusions had better cognitive insight than patients with delusions only [34
]. Our study assesses insight using the PANSS G12 item. This measure has shown good correlation with measures of insight in more specialized insight scales such as the Beck Cognitive Insight Scale, the Birchwood Self Rating Scale and the Schedule of Assessment of Insight – expanded version [35
]. Our results show that the more suicidal H group displayed better insight on all assessments. Furthermore, they scored consistently better than the D group on the cognitive component of the PANSS. Two recent meta-analyses have found that cognitive deficits and poor insight may be linked [37
Compared to the monosymptomatic patients, who are the focus of this paper, the patients who experienced both hallucinations and delusions were found to be more symptom burdened and have poorer global functioning. Notably, the dual symptom group scored closer to the D group with respect to suicidality and suicide rate. Furthermore, this dual symptom group had poorer insight scores than the single symptom groups at baseline and on all follow-ups. On the basis of these findings we could hypothesize that delusions could have a protective effect on suicidality, and that this possibly could be mediated by reduced insight associated with delusions. Overall, we feel our findings suggest a further link between hallucinations and suicidality that ought to be explored.
Other potential mediators of suicidality could be DUP and premorbid function. Previous literature has found poor premorbid function to be both a risk factor [39
] and a protective factor [29
] for suicidality. Long DUP has been related to suicidality in FEP [40
], while other FEP studies have failed to find this association [17
]. While longer DUP could explain some of the differences in suicidality between the groups before baseline, it is less certain how much it might contribute to the higher suicide rate in the H group at 5 years of follow-up.
This study is limited by the small sample of patients in the hallucinations only group. In fact such a clinical picture is not commonly seen. A related limitation is the small number, particularly in our H group, after the 2-year follow-up (n = 13 at the 2-year follow-up), when a significant number of patients in this group had been lost to suicide. As a consequence of the small sample size in the H group, advanced multivariate statistics were not performed. A further limitation of the present study is the lack of a standardized measure of suicide risk. The assessment tool provided has, however, formed the basis of indepth investigations of suicidality in FEP [43
In conclusion, this study contributes to a growing corpus of data that encourages a return to the study of individual symptoms and dimensions as important determinants of course in psychotic illnesses. A similar division of symptom groups could potentially aid further research into the genotypes and endophenotypes of schizophrenia spectrum disorders, and aid us in furthering our understanding of the various processes that drives psychosis manifest. This study also highlights a potential link between hallucinations and suicidality, with insight as a possible mediator. The subgroup of patients with a clinical picture dominated by hallucinations is particularly interesting, and its relation to suicidality needs to be further explored.