During my brush with insanity, I had no idea that there was anything wrong with me. In fact, if I noticed anything different in my world—and I usually didn’t—I blamed it on other people. To me, they were acting weird or behaving badly.

As a , I know very well that this lack of insight into your own illness—known as anosognosia—is a symptom of serious mental illness. Yet at the time, I couldn’t see it in myself because my brain (with its dysfunctional frontal cortex) prevented me from understanding and seeing things objectively.

In and , a lack of insight into one’s condition is thought to be a manifestation of the illness rather than denial or a coping mechanism, as it may initially seem to be. About 50 percent of people with schizophrenia and 40 percent with bipolar disorder cannot understand that they are sick, and have no real awareness of their condition and often won’t accept their diagnosis. If they experience or delusions, they don’t see them as a sign that something is wrong with their brains; even the most dramatic symptoms, such as hearing voices or believing that they are God, are indistinguishable from reality. Because those who suffer from lack of insight don’t believe they are ill, they’re often very resistant to treatment. They may not take prescribed medications or participate in behavioral therapies. There’s no cure, at present, for this kind of lack of insight.

During the period of my insanity, I didn’t think there was something seriously wrong with me. I thought I was absolutely fine mentally. But as my confusion grew, my brain filled in the gaps between what was in my head (my reality) and what was happening around me (which often didn’t make sense to me) with conspiracy theories. I became increasingly suspicious of my family and my coworkers. I was certain they were plotting against me.

Loss of insight into oneself, then, is a particularly frightening and worrisome aspect of mental illness. Today, I continue to worry that I could lose my mind again. Cancer can return at any time, and that means tumors in my brain could return and once again affect my sanity. I also know that if I lose my mind again, I won’t be able to tell. That’s why I’m obsessed about testing myself to make sure I can still remember things, numbers, events. I’m always asking people around me whether I am still making sense. Because if my mind goes again, I’ll be the last to know.