Schizophrenia is not really a mental illness. Most anthropologists agree that the prophets, fakirs, saints, and shamans of times past were schizophrenic, and there is a large body of research about this fascinating condition. For example, it’s been found that schizophrenics who are allowed to listen to their “voices” without interference tend to be much higher functioning than those whose “voices” are suppressed through drugs or therapy. This suggests that schizophrenics have a traditional role to perform in human culture, and that it has become a problem only because we have robbed schizophrenics of their jobs.
Schizophrenic artwork is rife with archetypes. It’s probably the single most common trait shared among schizophrenics. This suggests that schizophrenics see more that the general population, not less. The problem is that they are seeing the various archetypal symbols directly, without the translation into more concrete representational forms that the rest of us use.
In the case of David Icke, he is extremely perceptive in his observations. Those he calls “reptilians” really are reptilian in the sense that they are motivated by the reptilian portion of the brain, all rage and lust and greed and selfishness. The more gentle mammalian and primate parts of their brain, those which give us the capacity for empathy and compassion, are either malfunctioning or suppressed. Because David Icke perceives this directly rather than through the more abstract representations the rest of us use, he literally sees them to be lizards. A person wishing to understand the true form of the world beneath its surface could do worse than to pay close attention to the modern shamans like Icke.