Among first-episode psychosis patients, a family history of the condition negatively affects age at onset, negative symptoms, and the duration of illness and psychosis that are untreated, results from a large study showed.
The study "adds to an existing body of research suggesting that [family history] of psychosis is associated with a younger age at onset of psychosis, and is one of the first to demonstrate that FH acts similarly on age at onset at the prodrome," Michelle L. Esterberg, Ph.D., and her coinvestigator wrote (Psychiatry Res. 2012;197:23-8). "This is especially important given that earlier age at onset has adverse prognostic implications for illness course and outcome."
The investigators examined the impact of FH on the clinical presentation and help-seeking behaviors of 152 first-episode psychosis (FEP) patients who were hospitalized in a psychiatry unit of a large, university-affiliated psychiatry hospital or a suburban county psychiatric crisis stabilization unit. Patients were eligible for the trial if they were aged 18-40 years, could speak English, had an MMSE (Mini-Mental State Examination) score of 23 or greater, and were able to give informed consent.
Scales and measures used in the analysis included an interviewer-administered questionnaire, the SCID-I (Structured Clinical Interview for DSM-IV Axis I Disorders), the SOS (Symptom Onset in Schizophrenia) inventory, and the PANSS (Positive and Negative Syndrome Scale), wrote Dr. Esterberg of the VA Puget Sound Health Care System, Seattle.
The mean age of the study participants was 23 years, 90% were black, 75% were men, and 82% were hospitalized involuntarily. More than half (58%) were diagnosed with schizophrenia, and 15% were determined to have at least one first-degree family member with schizophrenia or another psychotic disorder.
The researchers reported that patients with a first-degree FH of psychosis had a significantly younger age at onset of the prodrome, compared with those who had no such history (mean age, 16 vs. 19 years, respectively; P less than .05), yet they did not differ significantly in duration of the prodromal period. Patients with a first-degree FH of psychosis also had a significantly younger age at onset of psychosis, compared with those who had no such FH (mean age, 18 vs. 22 years, respectively; P less than .01).
The investigators found that FH and sex interacted to influence the severity of negative symptoms, but not positive symptoms. Among patients overall, for example, men showed significantly more severe symptoms, compared with women (22 vs. 20%, respectively; P less than .01). When the analysis was limited to patients with FH, men had significantly more negative symptoms, compared with women (26% vs. 17%, respectively; P less than .01).
No significant difference was found in the duration of untreated illness (DUI) between patients with and without FH of psychosis, but patients with FH of psychosis had a longer duration of untreated psychosis (DUP), compared with patients who did not have FH of psychosis (P less than .05). Once again, sex differences emerged among patients with FH, with men having significantly more negative symptoms than did women (26% vs. 17%; P less than .01).
"It seems that FEP with a FH of psychosis spend a longer period of time with untreated psychosis relative to FEP patients without a FH, but statistically do not have an overall longer [duration of untreated illness]," the authors concluded. "Furthermore, the current findings are the first to show that sex of the patient should be taken into account when examining the relationships between FH and [duration of untreated illness/DUP] in that males with a FH of psychosis had a significantly longer [duration of untreated illness] and DUP relative to males with no FH of psychosis."
The researchers acknowledged certain limitations of the study, including its retrospective design, the fact that "assessing the presence of FH can ... be quite difficult, and [that] data collected from patients alone (without family member informants) may be less reliable. However, we made every effort to interview one or two family members in addition to the patient when possible to ensure that the most accurate data on FH were obtained."
They went on to recommend that "future research should focus on attempting to understand potential mediators and moderators of FH and its influence on the clinical presentation in schizophrenia."
The study was funded by the National Institute of Mental Health. The authors declared no relevant financial conflicts of interest.