Characteristics of the cohort participants
Of 510 individuals identified as having schizophrenia in 1994, 10 people
did not complete the evaluation. The remaining 500 participants (98.0%,
500/510) were available for follow-up (1994–2004), of which 46.6% were
male, 64.2% were married, and in 55.8% the family's economic status was less
than the mean.
All 500 participants included in 1994 were followed up from 1994 to 2004.
Informants were available for all these participants (100%). Information on
305 participants was provided by both the individual and their informants, and
information on 195 participants was provided by proxy informants alone.
Differences between never-treated and treated participants
At the end of the follow-up period, 132 participants (or their proxy
informants) (26.4%) reported never having received antipsychotic treatment and
368 (73.6%) reported having received antipsychotic treatment for their
schizophrenia (). Among
the treated individuals, there were 117 people (31.8%) who had been admitted
to a mental hospital, and 133 individuals (36.1%) who had accepted
antipsychotic treatment for less than 2 months. Compared with treated
participants (traditional Chinese medicine 45.7%, treatment by traditional
healers 61.7%), never-treated people had received significantly less
traditional Chinese medicine (13.6%) and treatment by traditional healers
Treated and never-treated groups
The characteristics of never-treated and treated participants are described
in . Compared with
treated participants, never-treated participants were significantly older,
less likely to be married, had a lower education level and fewer family
members. Caregivers of never-treated people were less likely to be a parent or
spouse. The never-treated individuals were significantly older at age at
onset, more likely to live alone, had longer duration of illness, more marked
symptoms and fewer previous suicide attempts.
Comparison between never-treated and treated participants
Current status and mortality
In 2004, as indicated in , there were no significant differences between never-treated
(70.5%) and treated participants (75.8%) in the percentage that had survived.
There were also no significant differences between never-treated (5.3%) and
treated participants (6.3%) in the proportion that were homeless. The
percentage of never-treated individuals who died by suicide (3.0%) was similar
to that in those who had been treated (4.6%). Deaths from other causes were
significantly more frequent in never-treated (21.2%) than treated (13.3%)
people during the follow-up period.
Current status of 500 cohort participants in 2004
There were no significant differences between male never-treated and
treated participants in the percentage surviving at follow-up, who had died by
suicide or other causes, or who were homeless. However, deaths from other
causes were significantly more frequent in female never-treated (20.0%) than
treated (10.4%) participants during the follow-up period. Among never-treated
individuals, there were no significant differences between men (44.8%) and
women (44.6%) in the percentage who were unable to work. Among treated
participants, there were significantly more men (41.6%) with an inability to
work than women (32.2%) (χ2 = 10.1, d.f. = 2,
The mortality rates and SMR of never-treated and treated participants are
shown in . There was no
significant difference between the mortality rate in never-treated and treated
individuals using Cox hazard regression analyses.
Death rates per 100 000 person–years and standardised mortality
There were no significant differences in suicide rates between
never-treated (345.1 per 100 000 person–years) and treated participants
(520.4 per 100 000 person–years) using Cox hazard regression analyses.
The SMR for never-treated individuals who died by suicide was 32.5, and for
treated individuals 46.7.
There were no significant differences in the mortality rate from other
causes (accidental and natural) between never-treated (2415.9 per 100 000
person–years) and treated participants (1199.9 per 100 000
person–years) using Cox hazard regression analyses. The SMR for
never-treated individuals who died from other causes was 9.5, and for treated
The survival probability for never-treated people in 2004 was 0.71 (95% CI
0.61–0.80). There was no significant difference in survival rate between
never-treated and treated participants (survival probability in 2004: 0.76,
95% CI 0.71–0.81) during the 10 years of follow-up (Log-rank test:
χ2 = 2.13, P>0.05).