Sociodemographics
This sample of untreated, first-episode ATPD and schizophrenia represent the clinical patient population of patients with ATPD and schizophrenia in UCH, Ibadan. In line with previous studies that found no significant differences between ATPD and schizophrenia with regard to the age at onset,
2,11,12 this study also found no significant difference in age at onset between patients with ATPD and patients with schizophrenia. The mean age at onset of the subjects with ATPD was 29.5 years, and, for the subjects with schizophrenia, it was 29.3 years. However, compared with the result in this study, Marneros et al., (2003) in Germany,
2 found a higher mean age at onset, 35.8 years and 35.3 years, respectively, for ATPD and schizophrenia; as such, age at onset did not differentiate between ATPD and schizophrenia.
Unlike the age at onset, the age at presentation in this study discriminated between ATPD and schizophrenia. With respect to a first episode of illness, ATPD was significantly more likely to present below the age of 25 years than was schizophrenia. After the separation of age at onset by sex, neither ATPD nor schizophrenia showed a differentiation in age at onset by sex. This is, however, at variance with previous reports of a higher age at onset of schizophrenia in women.
Contrary to previous studies that found marked female preponderance in ATPD,
2,9,12,13 this study found an equal gender representation in both groups. This finding, however, is in keeping with the reports by Shaltout et al.
14 in a study carried out in Qatar in 2007. A common factor to all the studies that found a preponderance of women in ATPD is that they were all conducted in Europe or in the United States. This result adds weight to the findings of cross-cultural differences in the incidence of the ATPDs.
9,15 It may also suggest that the epidemiology of ATPD may differ with geographic sites. Whether this is true needs further exploration. However, it has been shown that, comparable to the relationship between latitude and the incidence of certain disorders such as type I diabetes,
16 there is a significant positive association between latitude and the incidence of certain psychotic disorders.
17,18A comparison of the occupational status between ATPD and schizophrenia revealed some minor differences. A significantly higher proportion of subjects with schizophrenia (16.9%) were unemployed at the time of presentation, as compared with ATPD (4.2%). This trend was also found among subjects at follow-up in a study by Pillmann et al.
12 No significant differences were observed with regard to educational level. This corroborates the findings from earlier investigations by Marneros et al.
2 and Pillmann et al.,
12 that educational level did not distinguish between schizophrenia and ATPD. With regard to employment and education, Guinness (1992)
19 found an over-representation of education and paid employment in the ATPD group, as compared with schizophrenia.
19,20 In keeping with this finding, subjects with ATPD in the current study had a higher proportion of employed subjects than those in the schizophrenia group.
Patients with schizophrenia have lower rates of marriage,
21–23 in the same way that, in this study, subjects with schizophrenia were more likely to be single, whereas subjects with ATPD were more likely to be married. This finding by Watt and Szuleka is, however, at variance with the study by Pillmann et al. (2002),
12 which showed that being married did not differentiate significantly between the ATPD patients and schizophrenia patients. A bivariate analysis in the current study showed that compared with ATPD, subjects with schizophrenia were significantly more likely to be divorced, widowed, or separated. This could be due to the fact that patients with schizophrenia have poor social skills and are less likely to be in or maintain a heterosexual relationship.
21 Also, separation and divorce could also be a consequence of the illness when partners cannot cope with the stress associated with being married to spouses with mental illness.
Excitement was significantly more common among subjects with ATPD. This included features such as agitation, pressured speech, excessive arousal, and hyperactivity. Similarly, suspiciousness was significantly more common in schizophrenia than in ATPD (20.2% versus 6.5%). Features classified here included distrustfulness, persecutory ideas, hypervigilance, and delusions of persecution. Excitement and suspiciousness constituted significant differences regarding the phenomenology of ATPD and schizophrenia in this study. Excitement was more common in ATPD, whereas suspiciousness was more common in schizophrenia.
A comparison of general (non-psychotic) symptoms between the two groups revealed some differences. Anxiety and uncooperativeness were significantly more common in the ATPD group, whereas poor orientation, disturbance of volition, and preoccupation were significantly more common in the schizophrenia group. In a similar study by Marneros et al.,
13 a 5-year prospective study that explored psychopathological differences between ATPD and schizophrenia, the authors concluded that the most important differences between ATPD and schizophrenia were a higher frequency of rapidly-changing delusional topics, a rapidly-changing mood, and anxiety in ATPD, as compared with schizophrenia. This study corroborates this finding, as well. It is, however, important to note that differences in psychopathology are not sufficient to distinguish between ATPD as an entity and schizophrenia.
It is well established that people with schizophrenia have markedly high rates of unemployment. There is also evidence of associations between high rates of unemployment and greater symptomatology.
24 Correspondingly, in this study, unemployed subjects were four times more likely to have a diagnosis of schizophrenia than subjects who were engaged in a skilled occupation. Whisman and Baucom
25 showed that relationship discord is associated with mental ill-health. Furthermore, it has been shown that married people have better mental and physical health than their non-married counterparts.
25,26 In the current study, subjects who were widowed, divorced, or separated were twice more likely than those who were single to have a diagnosis of schizophrenia.
The factors that were predictive of ATPD included excitement and poor attention. Subjects who had these symptoms were more likely to receive a diagnosis of ATPD than those who did not have such symptoms. This finding is in keeping with reports by Marneros et al.
13 that ATPD showed marked affective symptoms, as compared with schizophrenia.
One strength of this study is that it has used a relatively large sample size for the ATPD group. Previous studies used much smaller sample sizes; for example in Germany, Pillmann et al.
12 used 26 patients; also in Germany, Pillmann et al. (2001)
27 used 42 patients; in Denmark, Jorgensen et al.
7 used 51 patients; in India, Susser et al. used 46 patients.
28 As such, this study has more power to detect a difference than the previously-mentioned studies. Secondly, since ATPDs are commoner in the less-developed countries, the findings of this study are more generalizable in Africa than previous studies, which were done in Europe and America. Hence, this is one of the first few studies on ATPD in Africa.
The results of this study should be considered in the context of its limitations, First, this was a review of case notes; a cross-sectional or prospective study would have better addressed the objectives. Missing/inadequate information is not uncommon in reviews of case notes; however, for subjects who had lengthy follow-up at the clinics or who had more than one episode of illness and presented at our clinics, several sociodemographic data were obtained from the case notes at such follow-up and later episodes. Consequently, there were very few missing sociodemographic data. Secondly, the diagnosis of ATPD and schizophrenia were not made with standardized diagnostic research instruments, such as the Structured Clinical Interview for DSM-IV (SCID). However, each case of ATPD or schizophrenia recruited into the study were reviewed by at least two specialists, first during the first episode, and second, at the commencement of this study, by the principal investigator. Cases that did not meet the criteria were excluded. Also, the duration of untreated psychosis was not assessed in this study. This could determine the severity and nature of symptoms that were observed. The duration of untreated psychosis is also associated with functioning.
In conclusion, in keeping with findings in Europe and North America, there are clinical and sociodemographic differences between ATPD and schizophrenia. However, a different set of features differentiates between the two conditions in Nigerians. It is recommended that physicians need to sensitize the populace to the differences in the signs and symptoms between ATPD and schizophrenia. This is important in predicting the course of both disorders, devising long-term treatment, promoting mental health, and reducing stigma. There is also a need for further cross-cultural research on the ATPD in Africans.