Psychiatric morbidity in the first-degree relatives of schizophrenic patients

Abstract

There is increasing evidence that genetic factors play a role in the etiology of schizophrenic disorders. One thousand eighty-nine first-degree relatives of schizophrenics and 1,137 controls were studied to discover their psychiatric morbidity. Psychiatric morbidity was found in 16.34% of the first-degree relatives (FDR) of schizophrenics (parents, 5.69%; siblings, 7.71%; offspring, 2.94%) as compared to 6.9% in the controls (P < 0.001). Schizophrenia was found in 8.3% of the patient group, which was significantly higher (0.2%) as compared to the controls. Schizoid-schizotypal personality disorder was found in 3.03% of FDRs of the schizophrenic group. Depressive disorder was found in 4.4% and 2.1% in the control and patient group, respectively, which was statistically significant. Morbidity risk of schizophrenia was found in 16.97%, 6.22% and 5.79% of schizophrenia, schizoid-schizotypal personality disorder and depressive disorder, respectively, in the FDR of schizophrenic group.

Role of cannabis and endocannabinoids in the genesis of schizophrenia

“…(1993) found a high percentage of relative risk among those cannabis abusers suffering from psychosis. Varma and Sharma (1993) found that 30% among siblings of schizophrenic patients use cannabis. A recent genetic study found that the link between cannabis and psychosis is stronger in those who have the Val/Val variant of the COMT gene (Caspi et al 2005) with odds ratio being high (10.9, from 2.2 to 54.1).…”

Psychiatric disorders in relatives of subjects with Alzheimer's disease

“…In agreement, family studies have consistently revealed that AD shows a familial aggregation indicating the relevance of genetic risk factors (Heston et al 1981, Heyman et al 1983, Breitner and Folstein 1984, Huff et al 1988, Farrer et al 1989, Korten et al 1993, Silverman et al 1994, Heun et al 2001). There is also evidence for familial aggregation of various other psychiatric disorders, e. g., affective disorders, anxiety disorders, alcoholism and schizophrenia (Gershon et al 1982, Sadovnick et al 1994, Varma et al 1997, Andrew et al 1998, Bierut et al 1999, Kendler et al 1999, Farmer et al 2000, Hill et al 2000, Lichtermann et al 2000, Scherrer et al 2000, Kendler et al 2001, Heun et al 2001). …”

Defining the schizophrenia phenotype

“…Results from subsequent family studies strongly supported a link between schizophrenia and schizotypal personality disorders [21][22][23][24][25][26][27]. A similar but weak relationship between paranoid and schizoid personality disorders and schizophrenia was observed in some, but not all, studies [27,28]. The lack of a strong link between schizoid personality disorders and schizophrenia is somewhat surprising considering that negative symptoms are frequently present in the relatives of schizophrenic patients.…”