Reply #95: There is no single schizophrenia gene [View All]

[Sparky McGruff]

Spoken as one who studies the genetic factors that underlie schizophrenia.

There are at least 20 genes that have been shown to increase the risk for schizophrenia, in one population study or another. All of these genes have also been shown not to be a factor in at least one other study... with the possible exception of one or two genes that have been found too recently for "confirmation" studies to be done... The significance of this (in my opinion) -- there are probably dozens of genes that can give you increased risk for schizophrenia. But it's not all genetics. Identical twins of schizophrenics have about a 50% risk of getting schizophrenia, which means that genetics is important, but not the end of the story.

There are also at least two dozen environmental factors (stress, drug usage, illness, etc) and two dozen developmental factors (maternal stress or malnutrition, exposure to certain teratogens, etc) that can also increase risk.

Part of the problem is that psychosis is really a symptom, not a disease in itself. We still don't know what the underlying disease is. Think of it like high blood pressure or heart disease. There's multiple genetic factors to each of these. But, there's also environmental factors (diet, lifestyle). If you're born with good genes, you can probably have a few extra helpings of the fried chicken. On the other hand, if you're born with semi-bad genes, you may not have any problems if you eat well, exercise, and have a low-stress lifestyle. In the extreme case, however, if you've got really bad genes, you're screwed no matter what.

Is drug usage one of these factors? Maybe. If you're at high risk (a close family member is schizophrenic), it's definitely a selling point for giving up the recreational drugs. Not a confirmed, casual factor, but definitely worth considering.