A farkon karni na 20, likitan psychiatrist Kurt Schneider ya lissafa siffofin bayyanar cututtuka na kwakwalwa wanda ya yi tunanin ya bambanta schizophrenia daga wasu cututtuka na kwakwalwa. Wadannan ana kiransu bayyanar cututtuka na farko ko bayyanar cututtuka na Schneider. Sun haɗa da raunin da ake sarrafawa ta hanyar wani karfi na waje, imani cewa ana shigar da tunani ko cirewa daga tunanin mutum, imani cewa ana watsa tunanin mutum ga wasu mutane, da kuma jin muryoyin hallucinatory da ke yin tsokaci game da tunanin mutum ko ayyukansa ko kuma suna tattaunawa da wasu muryoyin hallucinated. Ko da yake sun ba da gudummawa sosai ga ka'idodin bincike na yanzu, ba a yi tambaya game da takamaiman alamun farko ba.
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