A thesis statement is usually a sentence or two at the beginning of the essay or research report that summarizes what the focus will be. The thesis statement also usually provides a glimpse into the reasoning and the types of documentation to support the ideas before delving into greater detail in the body of the paper.
There are a number of possible things to discuss in a paper on The Woman in the Window relevant to mental illness. For instance, Anna suffers from agoraphobia, which the Merriam-Webster dictionary defines as an abnormal fear of helplessness often characterized by panic and the avoidance of public spaces. Anna makes her fear known to the reader early on when describing the difficulty she has in trying to leave her home and the coping mechanisms she calls upon to try to step over the threshold of her townhouse into the outside world.
Anna also self-medicates by mixing her medication with alcohol and drinking too much. In fact, she drinks to the point of blackouts, which is an underlying cause for her lack of credibility with the police investigating her claim that a woman was murdered in the Russell home.
It turns out that there has been a substantial amount of research done on mental disorders combined with self-medication. In fact, according to the National Center for Biotechnology Information,
It is widely recognized that frequent and prolonged substance use can produce or exacerbate mental disorders, regardless of whether substance use was initiated for the purpose of self-medication.
This could be one possible area to explore, and the thesis statement could be something along the lines of “mental disorders sometimes lead to self-medication with generally negative consequences.” Another potential topic could be the general stigma associated with mental disorders that exacerbates Anna’s lack of credibility with other characters.