Quetiapine is a second-generation antipsychotic, primarily intended for use in people with schizophrenia, type-one or -two bipolar disorder, or as an adjunct for major depressive disorder (NHS England, 2022). However, it has become increasingly popular off-label for use on its own for anxiety, sleep disturbance, depression, and other disorders such as emotional dysregulation in personality disorders. Due to its changing use, it is important to look at recent research that may indicate its usefulness for a range of mental health concerns.
Duncan et al (2016) published a study in the BMJ Open, which evaluated trends in the prescribing of quetiapine to adults in Alberta, Canada, between 2008–2013. The authors examined dispensed prescriptions, and diagnoses associated with people who were using quetiapine in 2013 and analysed administrative data from Alberta Health, the Alberta Pharmaceutical Information Network (PIN) Dispenses health data set, the Practitioner Payments (Fee-For-Service claims) health data set and the Population Registry health data set. This meant that the team could identify any person using quetiapine for each year from 2008–2013. The diagnoses were then evaluated by examining for diagnostic codes used by doctors when filing billings claims in 2013.
Use of quetiapine increased over the 6 years, with the number nearly doubling from 7.2 per 1000 people, to 13.3 per 1000 people receiving the drug. Throughout the 6 years, usage was higher in women at all times. Interestingly, the most common disorder that quetiapine was prescribed for was depression, being present in 56% of recipients. Bipolar disorder, which was one of the traditional reasons for prescribing the antipsychotic, was also present among diagnoses alongside other off-label diagnoses such as neurotic disorders and sleep disturbances.
Considering the known harms of the medication led the researchers to recommend a safer approach to prescribing, which will be explored later in this article. The researchers cited the fact that there had been little in the way of research to confirm a strong benefit from prescribing quetiapine off-label for depressive disorder, for example.
Another off-label use includes the more recent use of antipsychotics in neurodevelopmental disorders such as autism. Other antipsychotics have been found to potentially benefit people with autism through treating aggression in these patients.
Lopes et al (2023) published a recent systematic review and meta-analysis protocol in the BMJ Open for their work, which is set to begin, looking at the use of second-generation antipsychotics in autism spectrum disorder. The authors note that atypical antipsychotics have already been studied for the treatment of autism but little is known as to whether such medications are effective and safe when comparing between controlled and non-controlled settings.
Lopes et al (2023) therefore aimed to assess the efficacy and safety of second-generation antipsychotics for autism in randomised controlled trials and observational studies. Their review involved searches across multiple well-reputed databases, with primary outcomes being symptoms of aggressive behaviour, quality of life for the person or their carer, or discontinuation or withdrawal of antipsychotics because of adverse events. Secondary outcomes were non-serious adverse events and adherence to pharmacotherapy. The team was interested in the efficacy, but also possible harms, of the medication.
Patients can only be prescribed quetiapine by their GP or mental health team but it is important for everyone involved in the patient's care to be aware of the drug's effects. It can be extremely effective for some, while in others, the harms may outweigh the benefits. It is of great interest that this drug is prescribed so often for conditions not specified as indications for prescribing. This alone suggests the need for research that validates such use of the drug.
Unfortunately, despite their benefits, antipsychotic medications such as quetiapine are not without their disabling side effects or adverse events, although not everyone will experience these. In cases where the patient feels that quetiapine effectively treats their mental illness and improves their wellbeing overall, it should be examined what measures can be implemented in order to manage potential side effects, so as to reduce harm. The rise of quetiapine and its counterparts will be interesting to follow, as more research is published on its use for various disorders across the neuropsychiatric spectrum.