Sham P C, Jones P, Russell A, Gilvarry K, Bebbington P, Lewis S, Toone B, Murray R
Department of Psychological Medicine and Biostatistics, Institute of Psychiatry, London.
Br J Psychiatry. 1994 Oct;165(4):466-73. doi: 10.1192/bjp.165.4.466.
Although a genetic component in schizophrenia is well established, it is likely that the contribution of genetic factors is not constant for all cases. Several recent studies have found that the relatives of female or early onset schizophrenic patients have an increased risk of schizophrenia, compared to relatives of male or late onset cases. These hypotheses are tested in the current study.
A family study design was employed; the probands were 195 patients with functional psychosis admitted to three south London hospitals, diagnosed using Research Diagnostic Criteria (RDC), and assessed using the Present State Examination (PSE). Information on their relatives was obtained by personal interview of the mother of the proband, and from medical records. Psychiatric diagnoses were made using Family History-Research Diagnostic Criteria (FH-RDC), blind to proband information.
There was a tendency for homotypia in the form of psychosis within families. The lifetime risk of schizophrenia in the first degree relatives of schizophrenic probands, and the risk of bipolar disorder in the first degree relatives of bipolar probands, were 5-10 times higher than reported population risks. Relatives of female and early onset (< 22 years) schizophrenic probands had higher risk of schizophrenia than relatives of male and late onset schizophrenic probands. However, this effect was compensated in part by an excess of non-schizophrenic psychoses in the relatives of male probands.
These results suggest a high familial, possibly genetic, loading in female and early onset schizophrenia, but do not resolve the question of heterogeneity within schizophrenia.
尽管精神分裂症的遗传因素已得到充分证实，但遗传因素对所有病例的影响可能并非恒定不变。最近的几项研究发现，与男性或晚发性精神分裂症患者的亲属相比，女性或早发性精神分裂症患者的亲属患精神分裂症的风险更高。本研究对这些假设进行了检验。
采用家族研究设计；先证者为195例入住伦敦南部三家医院的功能性精神病患者，使用研究诊断标准（RDC）进行诊断，并使用现况检查（PSE）进行评估。通过对先证者母亲的个人访谈以及医疗记录获取其亲属的信息。使用家族病史-研究诊断标准（FH-RDC）进行精神病诊断，对先证者信息保密。
家族中存在以精神病形式出现的同病倾向。精神分裂症先证者一级亲属的精神分裂症终生风险，以及双相情感障碍先证者一级亲属的双相情感障碍风险，比报告的人群风险高5至10倍。女性和早发性（<22岁）精神分裂症先证者的亲属患精神分裂症的风险高于男性和晚发性精神分裂症先证者的亲属。然而，男性先证者亲属中过多的非精神分裂症性精神病在一定程度上抵消了这种影响。
这些结果表明女性和早发性精神分裂症存在较高的家族性，可能是遗传性负荷，但并未解决精神分裂症内部异质性的问题。
