Dysthyroidism in patients with psychiatric disorders in Morocco

Abstract

AimIn this study, we aimed to explore the association between dysthyroidism and psychiatric disorders and to verify whether there are sociodemographic or family variables that can determine the likelihood of this comorbidity.MethodsA descriptive, analytical, cross-sectional and retrospective study involved patients aged between 18 and 65 years, followed for thyroid pathologies comorbid with psychiatric disorders.ResultsThe participants were women with the median age of 52 years, 69.4% of patients presented a mood disorder, 30.6% had another psychiatric disorder, 6.1% presented a clinical goiter with a normal biological assessment, 8.2% presented hyperthyroidism and 85.7% presented hypothyroidism. Age, family situation, obstetrical, family and surgical ATCD, therapeutic compliance of psychiatric and thyroid disease and pharmacological treatment of psychiatric disorders are variables that present a statistically significant difference with a P < .05 between the two groups.ConclusionDysthyroidism and especially hypothyroidism is associated more with mood disorders than other psychiatric disorders in hospitalized patients.

Keywords

Introduction

The occurrence of mental disorders during endocrine pathologies has been established for more than a century. Conversely, psychological trauma may play a role in triggering certain endocrinopathies. The association between thyroid function and psychiatric disorders, especially mood disorders, was recognized more than 200 years ago.^1,2 Patients with mood disorders, including bipolar disorders and depressive disorders, have a high prevalence of somatic comorbidity compared to the general population.^3,4 Hypothyroidism is relatively common in these patients,⁴ this comorbidity would be correlated with a high risk of relapses, resistance to treatment, and suicide attempts.^5,6 It is well established that the use of psychiatric drugs (eg lithium) increases the risk of thyroid dysfunction.^3,4,7
The role of thyroid dysfunction in depression is recognized.⁸ Depressive symptoms often occur in patients with thyroid disorders and, conversely, patients with depression may have various thyroid abnormalities, including high or low levels of thyroid hormones.¹ Recent studies have confirmed a strong association between thyroid dysfunction in patients with mood disorders.⁹ For example, Ojha et al. reported that 21.4% of depressed patients had abnormal thyroid function, 11.4% met criteria for subclinical hypothyroidism, 5.7% for subclinical hyperthyroidism, and 4.3% for overt hypothyroidism.¹⁰ Regarding the relationship between thyroid dysfunction and bipolar disorder, a recent study by Ying Zhao et al. shows that early onset of bipolar disorder is correlated with higher rates of hypothyroidism.¹¹
In addition, thyroid dysfunction could have a significant influence on the cognition and emotion of those affected.¹ However, although previous studies have revealed associations between mood disorders and thyroid dysfunction, the roles of thyroid hormones, including free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), anti-thyroglobulin (TgAb) and anti-thyroid peroxidase antibodies (TPOAb) in the pathological mechanisms of mood disorders were not yet clear.^1,12
The main objective of this study was to explore the association between dysthyroidism and psychiatric disorders, to confirm this association especially in patients with mood disorders, and to verify whether there is a sociodemographic or family profile that may determine the likelihood of this comorbidity.

Materials and Methods

A descriptive, cross-sectional, retrospective study was conducted at the Ar-Razi Sale Psychiatric University Hospital in Morocco, from January 2014 to January 2020.Data CollectionThis study focused on patients aged between 18 and 65 years. The female sex was chosen in our study due to a high frequency of this comorbidity in women compared to men during our research at the Ar-Razi Psychiatric University Hospital for patients followed for thyroid pathologies comorbid with psychiatric disorders whose diagnosis was based on the DSM-5 diagnostic criteria. The records of male patients, female patients under the age of 18, and records with missing data were excluded. The clinical data was collected using a pre-established exploitation sheet with socio-demographic data (age, origin, profession, socio-economic level, marital status), clinical data (personal and family history, circumstances of consultation, revealing psychiatric manifestations). The collection of clinical data was carried out with respect for the anonymity and confidentiality of patients with medical records from the archives of the Ar-Razi Psychiatric University Hospital.Statistical AnalysisStatistical analysis was carried out using JAMOVI software for Windows 2016. Qualitative variables were presented as frequencies and percentages, quantitative variables were presented in mean standard deviation (SD) or median (interquartile range, IQR). The Chi-square (x2) test or Fisher’s exact test were carried out according to their particular application conditions to identify the differences in the proportions of the categorical variables between the two groups (Group 1: dysthyroidism comorbid with a mood disorder, Group 2: dysthyroidism comorbid with another psychiatric disorder other than a mood disorder). In addition, multivariate logistic regression analyses were used to identify risk factors. Independent variables presenting a statistically significant value with P < .05 between the two groups were taken into account in multivariate logistic regression.Reporting GuidelinesThis study was reported in accordance with the STROBE guideline.

Results

A total of 49 participants who met the study criteria were included in the study. The average age was 52 [41.59] years, more than half (53.1%) had a secondary education level, 55.1% were married, 95.9% lived with a family, 55.1% did not have a profession. The majority were without antecedents (73.5%), and 28.6% without a child. More than half (69.4%) had a mood disorder, 30.6% had another psychiatric disorder (not a mood disorder). The majority (85.7%) had hypothyroidism, 6.1% had a clinical goiter with a normal biological assessment, 8.2% presented hyperthyroidism.Psychiatric Disorder and DysthyroidismBy comparing the two groups and using the Chi-square (x2) test or Fisher’s exact test, we found that there is a statistically significant difference with a P < .05 for age, family situation, obstetrical history, family and surgical antecedents, therapeutic compliance of psychiatric and thyroid disease, and pharmacological treatment of psychiatric disorders (Table 1).Multinomial Logistic RegressionUsing multivariate logistic regression and adjusting for confounding factors, we concluded that being old, single, with surgical antecedents and poor treatment compliance are risk factors for developing a mood disorder (Table 2).

Discussion

According to the results of our study, the participants were women with a median age of 52 [41.59] years, more than half (53.1%) had a secondary education level, the majority had no background (73.5%), 69.4% of patients presented a mood disorder, 30.6% had another psychiatric disorder (without mood disorder), 6.1% presented a clinical goiter with a normal biological assessment, 8.2% presented hyperthyroidism and 85.7% presented hypothyroidism. Age, family situation, obstetrical, family and surgical history, therapeutic compliance with psychiatric and thyroid disease and pharmacological treatment of psychiatric disorders are variables that present a statistically significant difference with a P < .05 between the two groups.
Risk factors for developing a mood disorder were older age, being single, a history of surgery and poor adherence to treatment for psychiatric disorders and dysthyroidism. The female sex was chosen in our study due to a high frequency of this comorbidity in women compared to men. Several studies confirm our observation and found that women were associated with an increased risk of hypothyroidism comorbid with mood disorder.¹¹ The same results were obtained in a retrospective cohort study, which included 13,017 subjects, and revealed that the rate of depression was twice as high in women with TSH levels above 2.3 μIU/mL.¹³
In the present study the median age was 52 [41.59] years, and our results are consistent with a recent study showing that the prevalence of hypothyroidism in the subgroup with an age below 50 years was 8.53%, which was lower than that of patients over 50 years old (10.8%).¹¹ It is also consistent with another previous study that age was a risk factor for hypothyroidism.¹⁴ Our results show that the association between dysthyroidism and psychiatric disorders is frequent, especially with mood disorders in 69.4% of patients. These results are consistent with a recent study that shows an association between early onset of a psychiatric disorder and hypothyroidism, which may be present specifically in mood disorders rather than non-specifically in other serious mental illnesses, as this association has not been observed in schizophrenia.¹¹
According to our results and the results of previous studies, there is a relationship between thyroid dysfunction and mood disorders. Thyroid hormones have multiple effects on body homeostasis and metabolism.¹⁵ It is therefore not surprising that there are documented relationships between thyroid status and mood disorders. Specifically, thyroid disorders may increase the risk of mood disorders and the rate of depression is high in people with hypothyroidism.¹⁶ Thyroid hormones exert a profound influence on behavior and appear capable of modulating the phenotypic expression of major mood disorders. Indeed, a recent study found that there is evidence that triiodothyronine (LT3) can accelerate antidepressant response to antidepressants, and that LT3 can also increase the response to antidepressants in depression resistant to medical treatment.¹⁷ In the same study, adjunctive treatment with supraphysiological doses of levothyroxine (LT4) has shown its effectiveness in several studies, including rapid cycling and prophylaxis-resistant bipolar disorder, and in refractory acute unipolar or bipolar depression.¹⁷ Another explanation for this comorbidity is related to immune system abnormalities that are seen in both thyroid and depressive disorders, but although the most common cause of thyroid disorders is autoimmune disease, dysregulated immune function, and not autoimmunity, is more clearly documented in depression.^18,19
In addition to a high frequency of this comorbidity, resistance to antidepressant treatment is also documented. Bruce M. Cohen reported that depression in patients with high TSH levels is less severe but more resistant to treatment, and he observed a weaker antidepressant response, especially to selective serotonin reuptake inhibitors, in patients with major depression and higher TSH levels, with no correlation of response to serum T3 or T4 levels.²⁰ The complex relationship between selective serotonin reuptake inhibitors and thyroid function remains clarified. On the one hand, hypothyroidism alters responses to SSRIs,²⁰ and on the other hand, SSRIs cause a decrease in T4 levels, of free T4 and triiodothyronine (T3) without an appropriate compensatory response in TSH.²¹ One of the hypotheses to answer this question is that major depression is associated with a subtle chronobiological dysregulation of the hypothalamic-pituitary-thyroid axis (HPT).²²

Limitations

There are several limitations to this study. First, no causal relationship could be established due to the cross-sectional design of this study. Future studies should use a longitudinal study design to better explore the causal relationship of these variables in patients with this comorbidity. Second, the minimal number of patients was 49. Future research should include a wider range of patients with this comorbidity and both females and males. Third, some confounding factors that may play an important role in mood disorders should be incorporated in future research to better elucidate the pathological mechanisms underlying the association between thyroid dysfunction and psychiatric disorders. Finally, we did not have a healthy control group in this study. Therefore, our results should be considered preliminary, which merits replication in future studies before we can draw any conclusions.

Conclusion

Dysthyroidism and especially hypothyroidism are associated more with mood disorders than with other psychiatric disorders, and clinicians must look for this association so as not to miss hypothyroidism which, without treatment, will aggravate the clinical picture of a disorder from mood to resistance to pharmacological treatment and increased prevalence of suicide. Longitudinal cohort studies are needed to explore the clinical significance and potential mechanism of this association.

Declarations

References

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