Validity of Deficit Syndrome Classification
Deficit and nondeficit groups were compared on demographic and clinical variables at the time of classification (ie, 4.5-year follow-up) to ensure validity of the deficit/nondeficit categorization (see ). Deficit and nondeficit patients did not differ on age, education, social class, race, or WAIS information subtest scaled scores. Deficit syndrome patients displayed significantly more severe negative symptoms and did not significantly differ from nondeficit patients on positive symptoms or thought disorder/disorganization, although deficit patients showed a trend toward having less severe positive symptoms and disorganization at the time of deficit syndrome classification. Additionally, both deficit and nondeficit patients had a higher proportion of male than female subjects and a higher frequency of never having been married than having been married at index. These clinical and demographic characteristics suggest that the deficit syndrome group identified is highly consistent with the original deficit syndrome conceptualization.1,2
Demographic and Clinical Data for Schizophrenia Patients at the Time of Deficit Syndrome Classification
Temporal Stability of the Deficit Syndrome
Deficit syndrome diagnosis was calculated separately at the 2-, 4.5-, 7.5-, 10- , 15-, and 20-year follow-ups to determine stability of the deficit-nondeficit syndrome classification. Results indicated that of the patients classified as deficit at the 4.5-year follow-up, 67% were also classified as being deficit at the 2-year, 71% at the 7.5-year, 70% at the 10-year, 67% at the 15-year, and 75% at the 20-year follow-up. These stability estimates, over a considerably longer time frame, are generally consistent with data reported by other studies using the proxy case identification method.8,9
Here, we have used the percentage of patients at each follow-up as a measure of stability; however, we acknowledge that other analyses, such as survival analysis, might provide additional information on the stability of individual patients.
Medication Pattern of Deficit and Nondeficit Syndrome Patients
A somewhat higher proportion of deficit patients were prescribed antipsychotic medications at each follow-up (eg, 15-year follow-up deficit = 70% on antipsychotics; nondeficit = 48% on antipsychotics; P = .26; 20-year follow-up deficit = 78% on antipsychotics; nondeficit = 48% on antipsychotics; P = .31); however, the differences were not significant (P > .10 at all follow-ups), and both groups showed a fluctuating pattern regarding the percentage of patients prescribed antipsychotics over the 20-year period. Very few deficit and nondeficit patients were prescribed antidepressants, and there were no significant differences with regard to the percentage of deficit and nondeficit patients prescribed antidepressant medications at any of the 6 follow-ups.
Diagnostic Differences in Symptom Severity at 6 Follow-ups Over 20 Years
Using flat affect scores as a dependent variable, results of a 2 (diagnostic group) × 6 (follow-up) repeated-measures ANOVA indicated a significant between-subjects effect of diagnosis, F1,30 = 26.7, P < .001 (η2 = .43), a nonsignificant within-subjects effect of time course, and a nonsignificant diagnosis × time course interaction. One-way ANOVA indicated that deficit syndrome patients exhibited significantly more flat affect than nondeficit patients at the 2- (F = 2.15, P < .05), 4.5- (F = 13.1, P < .001), 7.5- (F = 2.08, P < .05), and 15-year follow-ups (F = 2.53, P < .05).
For each of the variables of delusions, hallucinations, and disorganization, there were no significant differences for the main effects of diagnosis and time or the diagnosis × time interaction. Although differences did not reach statistical significance, the deficit patients showed a trend toward becoming slightly (although not significantly) more disorganized with time, while the severity of disorganization decreased at later follow-up periods among nondeficit patients.
Diagnostic Differences in Global Outcome at 6 Follow-ups Over 20 Years
presents mean scores on global outcome for the 3 diagnostic groups at each of 6 follow-ups across a 20-year period. Using global LKP scores as a dependent variable, results of a 3 (diagnostic group) × 6 (follow-up) repeated-measures ANOVA indicated a significant between-subjects effect of diagnosis, F2,58 = 13.2, P < .001 (η2 = .38), as well as a significant within-subjects effect of time course, F5,58 = 2.31, P < .05 (η2 = .05). The diagnosis × time course interaction was nonsignificant. As can be seen in , results indicate that at each of the 6 follow-ups spanning the 20-year period, deficit syndrome patients displayed poorer global outcome than nondeficit patients, who in turn had poorer global outcome than patients with depression.
Global Outcome for Patient Groups Across 6 Follow-up Intervals Spanning a 20-Year Period
presents mean scores in employment, social functioning, and rehospitalizations for deficit, nondeficit, and depressed patients across the 6 follow-ups. Using Strauss-Carpenter Employment scores to assess work disability, the results of a 3 (diagnostic group) × 6 (follow-up) repeated-measures ANOVA indicated a significant between-subjects effect of diagnosis, F2,58 = 13.2, P < .001 (η2 = .38), nonsignificant within-subjects effect of time, and a significant time course × diagnosis interaction, F10,58 = 1.80, P < .05 (η2 = .08). One-way ANOVAs at each follow-up followed by post hoc Newman-Keuls tests indicated that schizophrenia patients displayed significantly greater work disability than depressed patients at each follow-up (P < .05), and deficit syndrome patients displayed greater occupational disability than nondeficit patients at all 6 follow-ups (P < .05). The magnitude of difference between deficit and nondeficit patients increased throughout the course of the disorder, with the greatest differences at the 15- and 20-year follow-ups.
Differences in Major Individual Areas of Functioning Across Diagnostic Groups
For both the Strauss-Carpenter Social Functioning and Rehospitalization scales, there were no significant differences for the main effects of diagnosis or time or for the diagnosis × time interaction. However, the between-subjects effect of diagnosis approached significance for rehospitalization, F2,58 = 2.83, P = .07 (η2 = .12). Although rehospitalization differences were not statistically significant, the pattern of means displayed among patient groups proved meaningful. Perhaps surprisingly, deficit syndrome patients showed fewer rehospitalizations than nondeficit patients at 5 of 6 follow-ups; however, these differences did not reach statistical significance (see ). Additionally, deficit syndrome patients had significantly fewer total hospitalizations across the course of illness than nondeficit patients (see ).
Diagnostic Differences in Periods of Global Recovery
presents the percentage of patients showing recovery for a year or longer across each of the 6 follow-ups. Chi-square analyses conducted at each of the 6 follow-ups indicated statistically significant differences in the rate of recovery among groups at the 2- (χ2 = 8.1, df = 2, P < .02), 4.5- (χ2 = 7.9, df = 2, P < .02), 7.5- (χ2 = 8.6, df = 2, P < .02), 10- (χ2 = 13.8, df = 2, P < .001), 15- (χ2 = 11.2, df = 2, P < .01), and 20-year (χ2 = 9.7, df = 2, P < .01) follow-ups. Differences between deficit and nondeficit syndrome schizophrenia patients were significant at the 10- (χ2 = 3.4, df = 1, P < .05), 15- (χ2 = 4.9, df = 1, P < .03), and 20-year (χ2 = 5.9, df = 1, P < .02) follow-ups. As can be seen in , results indicate that a smaller percentage of deficit syndrome patients than nondeficit patients or depressed patients were in recovery at each of the 6 follow-ups. Additionally, as can be seen in the figure, nondeficit patients are much more likely to recover later in the course of illness, with few patients meeting criteria for recovery prior to the 10-year follow-up; whereas deficit syndrome patients show low potential for a period of recovery early in their course and they show an even lower potential for a period of recovery later in their course. The lack of increased recovery over time in depressed patients can likely be attributed to these patients having relatively good outcome to begin with and that it would be hard for them to significantly improve over that baseline level.
Percentage of Patients in Recovery at each Follow-up Year.
Percentage of Patients Ever in Recovery Across 6 Follow-ups Over the 20-Year Period
The cumulative percentage of patients showing 1 or more periods of recovery over the 20-year period was also examined. Results indicate that significantly fewer nondeficit patients displayed at least 1 period of recovery over the 20 years in comparison to deficit patients, indicating that very few deficit patients show a period of recovery over the course of their disorder (χ2 = 9.7, df = 1, P < .01). Additionally, nonpsychotic depressed patients were significantly more likely to show at least 1 period of recovery than were schizophrenia patients, supporting numerous other reports indicating that the diagnosis of schizophrenia itself is associated with poorer outcome than nonpsychotic diagnoses (χ2 = 21.99, df = 2, P < .001) (see ).
Percentage of Patients Ever in Recovery.
Diagnostic Differences in the Total Number of Follow-up Periods in Recovery
The mean total number of recovery periods experienced by deficit, nondeficit, and depressed patients over the 20-year period was also examined. Results indicate that depressed patients (M = 3.53, SD = 2.12) experience significantly more periods of recovery than schizophrenia patients (M = 1.08, SD = 1.70) (F = 27.9, P < .001). Within the schizophrenia groups, deficit syndrome patients experienced significantly fewer total periods of recovery than nondeficit patients, F1,36 = 15.65, P < .001. Deficit syndrome patients on average were unlikely to experience even 1 period of recovery over 6 evaluations spanning the 20-year period (M = 0.29), whereas nondeficit patients (M = 1.54) were found to be in recovery in approximately 1.5 of the 6 total follow-up periods.