Recent evidence from a Canadian research group indicates that a combination of underlying factors may help explain why schizophrenia in women differs substantially from schizophrenia in men. Women affected by the severe mental illness schizophrenia often develop initial symptoms at a later age than their male counterparts. In addition, they often develop symptoms that differ in frequency or severity from those found in men with schizophrenia. In a study review published in 2015 in the Journal of Psychiatry and Neuroscience, researchers from Canada\u2019s McGill University looked for explanations for these differences in the two genders. These researchers identified several factors that may at least partially account for the ways in which schizophrenia impacts women in particular. Schizophrenia Schizophrenia belongs to a larger group of conditions officially known as \u201cschizophrenia spectrum and other psychotic disorders.\u201d Other illnesses in this group include schizoaffective disorder, schizotypal personality disorder, schizophreniform disorder, brief psychotic disorder and delusional disorder. The main defining symptom of schizophrenia and related conditions is psychosis, a highly destabilizing mental state that can include sensory hallucinations, delusional thought patterns or a combination of hallucinations and delusional thinking. Psychiatrists refer to psychosis as a \u201cpositive\u201d schizophrenia symptom; this means that it represents an unusual addition to the mental or physical reality of affected individuals. Other positive, psychosis-related symptoms of the disorder include an unusually jumbled or chaotic thought process, a thought process that halts unexpectedly in midstream and unusually agitated or subdued patterns of body movement. There are also \u201cnegative\u201d symptoms of schizophrenia. Psychiatrists use this term to refer to the absence or disruption of certain emotional\/behavioral states in a schizophrenic individual. Specific negative symptoms include a sharply reduced tendency to speak in social situations, loss of the ability to experience pleasurable sensations, a lack of facial or vocal emotional responsiveness and an impaired or absent ability to make plans or follow through on existing plans. As a rule, negative schizophrenia symptoms are harder to properly diagnose than positive symptoms of the disorder. Women and Schizophrenia Men develop schizophrenia significantly more often than women. The average man with the illness first experiences symptoms while in his early 20s or mid-20s. Conversely, the average affected woman first experiences symptoms while in her late-20s. Women also appear to experience another spike in their schizophrenia risks in their mid-40s (usually the upper end of the age range for the disorder). When symptoms first arise at this relatively advanced age, doctors and researchers sometimes refer to the condition as late-onset schizophrenia or LOS. In addition to having a largely gender-specific risk for schizophrenia, affected women in their 40s tend to have a higher number positive (i.e., psychotic) symptoms than the average schizophrenic man. When negative symptoms appear in a woman with LOS, they frequently have a relatively muted effect. Why Is There a Difference? In the study review published in the Journal of Psychiatry & Neuroscience, the McGill University researchers used an analysis of previously conducted studies to identify factors that may explain the gender-specific manifestations of schizophrenia. The researchers focused much of this analysis on the ways in which normal brain development helps determine the likelihood and course of the illness in women as opposed to men. Among their findings, they note that women typically develop their full complement of grey matter (the brain\u2019s main nerve cells) at an earlier age than men. They posit that rapid grey matter development may essentially stabilize women\u2019s brain function at an earlier age, and thereby lower schizophrenia risks. The researchers also believe that women\u2019s brains may have chemical environments that make schizophrenia less likely to occur. In the past, quite a few studies have focused on the presence of estrogen, women\u2019s primary sex hormone, as a possible limiting factor in women\u2019s schizophrenia risks. In this role, the hormone may decrease the risks for psychosis, in addition to delaying the age at which the disorder appears. However, the McGill researchers find limited evidence for the protective role of estrogen, especially since theories centered on the hormone can\u2019t explain why women with late-onset schizophrenia commonly have different symptoms than schizophrenic men. They believe that any estrogen-related effects likely appear in combination with genetic factors unique to the individual, as well as with the rising influence of stress hormones in older women. Essentially, women predisposed to LOS may develop the condition when their estrogen levels start to drop and their stress hormone levels start to rise.