Mental illness and insomnia are often co-morbid (happen at the same time), and indeed insomnia is a symptom of most mental illnesses. This type of insomnia is properly secondary insomnia – the doctor knows the cause, the mental illness, and the insomnia will be relieved if the underlying illness is cleared up. Antipsychotic medicines are powerful drugs that affect the brain. They are rarely used just to treat a patient’s insomnia – there are many better general purpose sleeping pills – but if the attending physician feels antipsychotic drugs are called for due to other conditions, they often end up being the main treatment for the insomnia.
When people without mental illness take antipsychotics, there is no effect on sleep. But when people with schizophrenia take them, there is an increase in sleep time, including an increase in time spent in slow-wave deep sleep. REM efficiency - the unbrokeness of REM periods - also improves.
The antipsychotic drugs are usually tranquilizers and allow the body to rest and become ready for sleep in addition to the effects they have on the brain. Second-generation antipsychotics are the ones in use today and like other prescription drugs they are approved by the FDA and “labeled” for specific illnesses, or “indications”. Doctors have the freedom to prescribe them off-label, and experienced psychiatrists often do so.
Quetiapine is a schizoprehia drug sold under the brand name Seroquel by AstraZeneca. The patent expired in 2011 so generics should be available. AstraZeneca is also trying to market a controlled release version. Like other antipyschotics, quetiapine is a dopamine receptor agonist and also influences other neurotransmitters.
Olanzapine is a widely used psychiatric drug. Eli Lilly held the patent until 2011 and sold it (and still sells it) under the name Zyprexa. It is not given to people with dementia because it has been implicated in an increased risk of stroke. Eli Lilly had to pay a fine for marketing it for Alzheimer’s Disease even though they had no evidence it worked for that condition. Like the other antipsychotic drugs, olanzapine is rarely prescribed just for insomnia, although doctors have the option of doing so if they feel it is warranted. When prescribed for sleep problems, the dosage is much lower than for psychosis.
Riseridone (brand name Risperol) is approved for a number of psychiatric conditions and used fairly widely. The side effects of cognitive impairment are more prevalent in older people with dementia. It also causes weight gain in addition to the side effects that most antipsychotics cause (pain, digestive upset). Some patients find it actually makes their insomnia worse.
Risperidone was the subject of a public health warning in 2011. It was being confused with the similar sounding drug ropinirole (brand names Risperdal and Requip) and patients were being harmed.
These drugs are in pill form (oral delivery) and stay in the body relatively long times before they are broken down. This is another difference from conventional sleeping pills (the Z-drugs) which have half-lives such that the patient is not too groggy the next day.
Antipsychotics can leave the person feeling drugged and not alert enough to drive, which is one more reason they are rarely used for just insomnia. There is also the question of how long a patient stays on an antipsychotic if the main problem is insomnia. Some doctors may prescribe this type of drug at first to “get the brain back on track” and then switch to another medicine.