Serious Adverse Effects: Metabolic Syndrome

Metabolic syndrome puts a name to a phenomenon we will all be familiar with as RMNs. It’s both a life-threatening and commonplace adverse effect of commonly-used mental health medications. However, nurses can encourage a range of interventions to significantly reduce the likelihood of it developing. In other words, RMNs need to know about metabolic syndrome. Find out what it is, what causes it, and what the pathological risks are here.


What is Metabolic Syndrome?

Metabolic Syndrome is also known as Cardio-metabolic Syndrome, Syndrome X or Metabolic Syndrome X. It’s a progressive disorder, strongly associated with abdominal obesity. If left to progress, it leads to type 2 diabetes mellitus and various forms of cardiovascular disease. However it’s effects can be reversed with the appropriate interventions.


Lifestyle Risk Factors and Effective Interventions

Common unhealthy lifestyle habits have been associated with the development of metabolic syndrome. There are some rather obvious interventions to reverse its progression:

Unhealthy Lifestyle Habit Therapeutic Intervention
Inactivity Increase of physical activity
Excessive calorific intake / diet high in sugar and fat Balanced and healthy diet
Smoking Smoking cessation
High alcohol intake Alcohol intake reduction


Less Avoidable Risk Factors

It’s important to stress that metabolic syndrome is not completely synonymous with obesity. Not everyone who is classified as obese will have metabolic syndrome. Furthermore, only three of the following criteria are required for a diagnosis of metabolic syndrome:

  • Central / abdominal obesity
  • Elevated blood pressure
  • Hypertriglyceridaemia (raised triglycerides)
  • Low serum levels of high-density lipoprotein (HDL) cholesterol
  • High fasting blood glucose levels

This means that obesity isn’t strictly necessary for a diagnosis of metabolic syndrome. It’s also worth acknowledging that it takes less of an unhealthy lifestyle for some to develop metabolic syndrome than others. There are various other risk factors, some of which are completely unavoidable:

  • Age: The chances of developing it increase with age.
  • Gender: Women are more prone to developing it than men.
  • Genetics: The effects of our genes on metabolic syndrome’s development are subtle but detectable. This is the case for shared genetic material between families and also ethnicities: Risk is increased for those with a parent or sibling who has diabetes, and for populations of South Asian and Afro-carribean origin.
  • Other health conditions: Polycistic ovaries, gallstones, sleep apnoea, chronic inflamation, the use of various medications, and various mental illnesses.


Mental Health Risk Factors

We are likely to see many of the lifestyle risk factors listed above in mental health service users. However there are other significant risk factors unique to those with mental illness:

Antipsychotics: Second generation antipsychotics greatly increase the chances of metabolic syndrome. Olanzapine and clozapine in particular, but risperidone and quetiapine also carry a risk. It’s suspected that this is due to their antagonism of serotonin 5HT2C  and histamine H1 receptors. The blocking of 5HT2C receptors leads to increased insulin resistance, whilst blocking H1 receptors reduces the body’s metabolic rate (Ho et al., 2014).

Other psychotropic medication: Sodium valproate, lithium and triclyclic antidepressants are all linked to insulin resistance and weight gain. SSRIs  can also cause weight gain with long-term use.

Shared biological mechanisms: Elevation of inflamatory proteins called cytokines (e.g. TNF-α, CRP and IL-6) have been repeatedly observed in metabolic syndrome. The same is also true of both depression and schizophrenia (Ho et al., 2014). Although it’s not clear what the shared mechanism may be, first-episode schizophrenia is linked to insulin resistance (Perry et al., 2016). Depression has also been repeatedly linked to elevated baseline serum cortisol levels. Cortisol promotes the formation of glucose from glycogen stores. As insulin facilitates the opposite to occur, excessive levels of cortisol can lead to insulin resistance (Ho et al., 2014). Subsequently, people with depression have around a 60% increase in risk of developing type 2 diabetes (Mezuk et al., 2008).


Other Medicines Associated with Metabolic Syndrome Onset

From Wofford, King and Harrell (2006)

  • Thiazide diuretics (e.g. bendroflumethiazide)
  • Beta blockers (e.g. atenolol, propranolol)
  • Oral contraceptives
  • Protease inhibitors (antiretrovirals e.g lopinavir and ritonavir)


Internet Resources on Metabolic Syndrome

Further academic reading

For qualified NHS staff, see the Resources page for how to access these articles.

  • Ho, C.S.H., Zhang, M.W.B., Mak, A. & Ho, R.C.M. 2014, “Metabolic syndrome in psychiatry: advances in understanding and management”, Advances in Psychiatric Treatment, vol. 20, no. 2, pp. 101-112.
  • Mezuk, B., Eaton, W., Albrecht, S. & Golden, S. 2008, “Depression and Type 2 Diabetes Over the Lifespan A meta-analysis”, DIABETES CARE, vol. 31, no. 12, pp. 2383-2390.
  • Perry, B., McIntosh, G., Weich, S., Singh, S. and Rees, K. 2016. “The association between first-episode psychosis and abnormal glycaemic control: systematic review and meta-analysis”, The Lancet Psychiatry, vol. 3, no. 11, pp.1049-1058.
  • Wofford, M., King, D. and Harrell, T. 2006. “Drug-Induced Metabolic Syndrome”, The Journal of Clinical Hypertension, vol. 8, no. 2, pp.114-119.

Picture credits:
Body mass index chart (2006) by InvictaHOG. From Wikimedia Commons.

Posted by Ben Murphy

Ben is a registered mental health nurse, holds an MSc in Genetic Counselling, and is a lecturer in Biological Sciences at City, University of London. Amongst other things, he teaches anatomy, physiology, pathophysiology and therapeutics to pre-reg. and post-reg. nursing students.

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