“There is mounting evidence that for people with psychotic disorders, insomnia is correlated with more severe delusions, hallucinations, and disorganized thinking and behavior, and predicts onset or exacerbation of psychotic symptoms in both chronic and first-episode psychosis,” Dr. Klingaman said. “Poor sleep quality predicts dissatisfaction with social relationships, daily activities, emotional functioning, and quality of life. Chronic insufficient sleep causes deficits in cognitive functioning generally, which could be exacerbated among people with schizophrenia. Poor sleep quality is associated with impaired sleep dependent memory consolidation. In schizophrenia, poor sleep quality is associated physical health effects as well, like peripheral immune measure alterations, increased proinflammatory cytokine production, altered cortisol and melatonin levels, and can also contribute to obesity and cardiovascular illness, which are highly prevalent among people with schizophrenia.

“Broadly speaking, in psychiatric disorders, there is a dysfunction in some of the very important neurotransmitters and these neurotransmitters include dopamine, norepinephrine, and serotonin,” said Dr. Dasgupta. “We are manipulating those when we medicate for a psychiatric disorder. And it is also those hormones that regulate our sleep/wake cycle. So it doesn’t surprise me that when you have a dysregulation of these neurotransmitters or hormones, that they result in both psychiatric disorders as well as sleep problems.”

Patients with sleep deprivation or poor sleep quality are at higher risk of daytime fatigue, confusion, frustration—even worsened pain issues, Dr. Dasgupta said. “Those are some of the issues that people with psychiatric disorders face every day. The least we can do is try to take that away by addressing night-time issues whether it be sleep apnea or trying to get them better sleep by addressing insomnia.”

Diagnostic classifications for insomnia have changed, Dr. Klingaman noted. “In the DSM-IV, insomnia was classified as either primary or secondary; secondary was used to distinguish insomnia as a result of a medical or mental health condition or of medications or substances. But in the DSM-5, this distinction was removed.”

That’s an important shift, Dr. Klingaman said: “It recognizes that even in the presence of these other circumstances, insomnia warrants independent clinical attention in its own right. So, for people with schizophrenia spectrum disorders, although insomnia may have initially started due to something specific to the illness itself or its treatment, it shouldn’t be assumed that treating those factors will make insomnia go away. It should be targeted on its own.”

Diagnosis requires a comprehensive sleep history and sleep diaries, Dr. Klingaman said. “In my experience, many people with schizophrenia are able and willing to complete nightly sleep diaries. Also pertaining to those with possible circadian rhythm dysfunction, actigraphy may be used to clarify diagnosis; in our experience, people with schizophrenia can use this successfully for multiple nights at home without problems.”

When diagnosing restless legs syndrome, it is important to determine whether or not antipsychotic-induced akathisia is playing a role, she emphasized.