Belsomra does not treat anxiety, and is not approved by the FDA for anxiety, it is only approved to treat insomnia. One study that included 40 psychiatric inpatients from Kusatsu Hospital in Hiroshima, Japan reported that Belsomra improved sleep quality and did reduce the severity of anxiety, but more research is needed. Belsomra can cause anxiety in some people, or make pre-existing anxiety worse, with some people reporting major anxiety at night.