Introduction
Tinnitus is a symptom defined as the perception of sound in the ears or head when no outside sound is present. It can be divided into subjective and objective types. Tinnitus is considered objective when it is audible to another person besides the patient; this type is much less common than subjective tinnitus. The symptom affects approximately 15 per cent of the population worldwide.Reference Coelho, Sanchez and Bento1 Although tinnitus may occur at any time in life, most patients are aged between 40 and 80 years, and prevalence rises to 33 per cent in patients aged over 60 years.Reference Jastreboff and Hazell2
Tinnitus has been associated with a variety of psychological and psychiatric disorders.Reference Lynn, Bauch, Williams, Beatty, Mellon and Weaver3–Reference Malakouti, Nojomi, Mahmoudian and Salehi6 Studies show that 48–60 per cent of patients with chronic tinnitus who are annoyed by the symptom have an associated diagnosis of major depression.Reference Sullivan, Katon, Dobie, Sakai and Russo7, Reference Harrop-Griffiths, Katon, Dobie, Sakai and Russo8 Simpson et al. observed psychiatric diseases in 46 per cent of patients with tinnitus.Reference Simpson, Nedzelski, Barber and Thomas9 In a study by Zoger et al., 45 per cent of tinnitus patients were found to have anxiety disorders.Reference Zoger, Svedlund and Holgers10
Many other studies show a strong correlation between tinnitus severity and psychological and psychiatric problems such as mood disorders, reduced concentration, irritability and loss of control.Reference Zoger, Svedlund and Holgers10–Reference Oishi, Shinden, Kanzaki, Saito, Inoue and Ogawa17 Most studies indicate a relationship between tinnitus annoyance and the presence of certain psychiatric diagnoses and specific personality traits.Reference Unterrainer, Greimel, Leibetseder and Koller4, Reference Holgers, Zoger and Svedlund11, Reference Tyler and Baker18–Reference Langguth, Kleinjung, Fischer, Hajak, Eichhammer and Sand20 Unterrainer et al. described depression and tinnitus intensity as the best predictors of the perception of tinnitus severity and of consequent annoyance.Reference Unterrainer, Greimel, Leibetseder and Koller4
Langguth et al. confirmed the importance of anxiety and depression as predictors of tinnitus severity using the Tinnitus Handicap Inventory.Reference Langguth, Kleinjung, Fischer, Hajak, Eichhammer and Sand20 The relationship between certain personality traits, depressive mood and tinnitus severity is highly relevant to the diagnosis of tinnitus and to the prognosis in terms of the degree of handicap related to tinnitus.Reference Langguth, Kleinjung, Fischer, Hajak, Eichhammer and Sand20, Reference Russo, Katon, Sullivan, Clark and Buchwald21 Depression frequently occurs with tinnitusReference Harrop-Griffiths, Katon, Dobie, Sakai and Russo8 and usually increases the functional handicap of affected patients.Reference Sullivan, Katon, Russo, Dobie and Sakai22
It is important to identify and adequately treat the mental disorders associated with tinnitus because these disorders might greatly affect a patient's quality of life. The present study aimed to systematically review the literature on the occurrence of psychiatric diagnoses in the tinnitus-affected population, and to correlate the presence of a psychiatric disorder with tinnitus-related annoyance and severity.
Materials and methods
In order to select articles for this review, electronic searches of PubMed, ISI Web of Science and SciELO databases were performed. Only those studies published between January 2000 and December 2012, and which utilised the most common psychiatric diagnosis criteria and tinnitus annoyance measurements, were included. The search revealed a total of 153 articles. The terms used as keywords were ‘tinnitus’, ‘psychiatric’, ‘mental disorders’ and ‘psychological’. The terms were matched to generate a more specific search.
The main requirement for article inclusion was the presentation of original research on psychiatric disorders and tinnitus, with a focus on the diagnosis of anxiety and/or mood disorders. The research participants had to be aged over 18 years and tinnitus had to be present for at least 3 months. Only articles evaluating patients with subjective tinnitus were included. Studies that included psychosis cases, or patients with personality or somatoform disorders, were excluded. Other exclusion criteria were: patients who presented with tinnitus related to acute and chronic otitis media, outer-ear diseases, or conductive or mixed hearing losses; patients who had undergone ear surgery; patients with Ménière's disease, somatosensory tinnitus or tinnitus related to metabolic diseases; and studies that evaluated only psychological aspects rather than psychiatric diagnoses or symptoms.
Only papers written in English or Portuguese were included in the final selection. Review articles, book chapters, dissertations and letters to the editor were excluded.
Manual searches of the selected articles were performed. Ultimately, 16 papers were chosen for inclusion in this review.
Results
For psychiatric evaluation, many studies (n = 9) used more than one scale to define the symptoms and diagnose the patients. The most common questionnaires used were: the Structured Clinical Interview for the Diagnostic and Statistical Manual for Mental Disorders (‘DSM’) edition III or IV (n = 5); the Hospital Anxiety and Depression Scale (n = 5); the Beck Depression Inventory (n = 5); or the Mini International Neuropsychiatric Interview (n = 2). Only one article used the Beck Anxiety Inventory. Other instruments used were: the Hopkins Symptoms Checklist, the Comprehensive Psychopathological Rating Scale, the Toronto Alexithymia Scale, the State–Trait Anxiety Inventory, the Symptom Checklist 90 Revised, the Anxiety Sensitivity Index, the Composite International Diagnostic Interview Short Form, the Maudsley Obsessional Compulsive Inventory and a self-rating depression scale.Reference Malakouti, Nojomi, Mahmoudian and Salehi6, Reference Zoger, Svedlund and Holgers10–Reference Oishi, Shinden, Kanzaki, Saito, Inoue and Ogawa17, Reference Bartels, Middel, van der Laan, Staal and Albers23–Reference Adoga, Adoga and Obindo29
When evaluating tinnitus severity and impact on quality of life, six studies used the Tinnitus Handicap Inventory, two used the Tinnitus Severity Questionnaire and two used the Tinnitus Reaction Questionnaire. The other scales used were the Nottingham Health Profile and the Tinnitus Severity Index. Several studies simply evaluated the prevalence of psychiatric disorders in patients with tinnitus versus those with no tinnitus. Some studies devised a specific self-completion questionnaire or used a semi-structured interview technique.
Fifteen of the 16 reviewed studies indicated a high prevalence of psychiatric diagnoses in patients with tinnitus. Nine of the studies showed a significant correlation between the presence and severity of these psychiatric disorders and the severity and annoyance of tinnitus; that is, the presence of co-morbid psychiatric disorders worsened the prognosis of tinnitus-related disability.
Bartels et al. evaluated 265 tinnitus patients using the Hospital Anxiety and Depression Scale, and found that 41 per cent had no psychiatric symptoms.Reference Bartels, Middel, van der Laan, Staal and Albers23 Of the patients with psychiatric symptoms, 10.2 per cent had anxiety only, 9.8 per cent had depression only, and 39.2 per cent had depression plus anxiety. The researchers concluded that concurrent anxiety and depression have an additive effect, which reduces patients' general and tinnitus-specific health-related quality of life and increases maladaptive coping mechanisms.
Malakouti et al. found a high prevalence of at least one axis I lifetime psychiatric diagnosis (of the Diagnostic and Statistical Manual of Mental Disorders) in tinnitus patients (56 per cent prevalence in male patients vs 69 per cent in female patients; p = 0.01).Reference Malakouti, Nojomi, Mahmoudian and Salehi6 The most prevalent disorders were anxiety and major depression. The frequency of major depression, anxiety and somatoform disorders was significantly higher in females than in males (p < 0.01). In total, 75 per cent of women received a severe score on the Tinnitus Handicap Inventory compared with 63.9 per cent of men. With regard to psychiatric diagnoses or symptoms, the study showed no significant association between Tinnitus Handicap Inventory scores and the presence of mental disorders.
A study by Salonen et al. was the only one to examine alexithymia in tinnitus patients.Reference Salonen, Johansson and Joukamaa14 The researchers observed that those participants with tinnitus who were not annoyed by it were most commonly alexithymic (odds ratio = 2.2, 95 per cent confidence interval (CI) = 1.3–3.6) with a high Toronto Alexithymia Scale score. The patients who were annoyed by their tinnitus were also commonly alexithymic when compared with the patients without tinnitus (odds ratio = 1.7, 95 per cent CI = 1.0–2.9), and had a high Toronto Alexithymia Scale score, although the score was lower than for the non-annoyed group. Depression was associated with severe tinnitus among women in a pairwise analysis, but this association disappeared in a multivariate analysis. Overall, there was an association between alexithymia and tinnitus, but a detailed analysis showed that alexithymia was not helpful in explaining tinnitus annoyance.
A study by Ooms et al., in which136 patients were evaluated using the Beck Depression Inventory and Tinnitus Handicap Inventory, found depressive symptoms in 16.9 per cent of patients with mild tinnitus, in 10.3 per cent of those with moderate tinnitus and in 5.9 per cent of severe tinnitus patients.Reference Ooms, Meganck, Vanheule, Vinck, Watelet and Dhooge24 Of the patients with severe tinnitus, 17.2 per cent reported severe depressive symptoms. No patients with catastrophic tinnitus reported severe depressive symptoms. The Tinnitus Handicap Inventory and Beck Depression Inventory scores were significantly correlated. To check whether the correlation could be explained by content overlap, a linear regression was performed with Tinnitus Handicap Inventory scores as the dependent variable and scores on the three subscales of the Beck Depression Inventory II as the independent variables. Only the somatic depression subscale significantly predicted subjective tinnitus severity. The authors suggested that the relationship between depression and tinnitus is far less obvious than is currently assumed. It is important to distinguish between somatic symptoms that are a consequence of tinnitus and somatic symptoms that are indicators of depression.
One study by Folmer et al. specifically evaluated the influence of obsessive-compulsive disorder on tinnitus patients. The authors found that a high Maudsley Obsessional Compulsive Inventory score correlated with high values for tinnitus loudness and high scores on the Tinnitus Severity Index.Reference Folmer, Griest and Martin16 A study by Andersson et al. found a very high prevalence of psychiatric disorders in tinnitus patients, particularly obsessive-compulsive disorder, which was present in 83 per cent of tinnitus patients.Reference Andersson, Carlbring, Kaldo-Sandstrom and Strom26
A Brazilian study by Mathias et al. also found a very high prevalence of at least one psychiatric diagnosis in tinnitus patients (82 per cent of the patients fulfilled the criteria).Reference Mathias, Mezzasalma and Nardi25 Forty per cent of the patients had panic disorder, 40 per cent had depression and 34 per cent had generalised anxiety disorder.
A summary of the articles included in this review is presented in Table I.
Table I Summary of studies included in the review
THI = Tinnitus Handicap Inventory; BDI = Beck Depression Inventory; SDS = self-rating depression scale; STAI = State–Trait Anxiety Inventory; SCID = Structured Clinical Interview for DSM Disorders; DSM = Diagnostic and Statistical Manual for Mental Disorders; MINI = Mini International Neuropsychiatric Interview; VAS = visual analogue scale; BAI = Beck Anxiety Inventory; SCL-90-R = Symptom Checklist 90 Revised; TSI = Tinnitus Severity Index; MOCI = Maudsley Obsessional Compulsive Inventory; SAI = State Anxiety Inventory; TRQ = Tinnitus Reaction Questionnaire; HADS = Hospital Anxiety and Depression Scale; TAS-20 = Toronto Alexithymia Scale; TSQ = Tinnitus Severity Questionnaire; CPRSA = Comprehensive Psychopathological Rating Scale; edn = edition; TQ = Tinnitus Questionnaire; ASI = Anxiety Sensitivity Index; CIDI-SF = Composite International Diagnostic Interview Short Form; OCD = obsessive-compulsive disorder
Discussion
In this study, only auditory tinnitus related to sensorineural hearing loss was considered, and not tinnitus associated with specific ear disease, to make the sample homogeneous with respect to the cause of tinnitus and behaviour of affected patients. Our review focused on the diagnosis (not the symptoms) of axis I psychiatric disorders, according to the Diagnostic and Statistical Manual for Mental Disorders edition III or IV and the International Classification of Diseases version 10. Our exclusion criteria were based on these specifications.
Most of the studies included in this review revealed a clear correlation between tinnitus severity and the presence of psychiatric disorders; there was a high prevalence of such disorders and symptoms in tinnitus patients.Reference Zoger, Svedlund and Holgers10–Reference Oishi, Shinden, Kanzaki, Saito, Inoue and Ogawa17 Most patients were affected by mood disorders, especially depression and anxiety disorders.Reference Malakouti, Nojomi, Mahmoudian and Salehi6, Reference Zoger, Svedlund and Holgers10–Reference Crocetti, Forti, Ambrosetti and Del Bo15, Reference Oishi, Shinden, Kanzaki, Saito, Inoue and Ogawa17, Reference Bartels, Middel, van der Laan, Staal and Albers23, Reference Mathias, Mezzasalma and Nardi25–Reference Adoga, Adoga and Obindo29 However, many other psychiatric disorders and symptoms may be present, and these may significantly affect tinnitus severity. Thus, there may be a cause-and-effect relationship between tinnitus and psychiatric disorders. However, despite the high rate for tinnitus coinciding with mental disorders, especially depression and anxiety, a cause cannot be directly established. Severe tinnitus may cause psychological discomfort; alternatively, the presence of depression and anxiety may reduce an individual's tolerance of tinnitus, leading to exaggeration of the symptoms.Reference Malakouti, Nojomi, Mahmoudian and Salehi6
Tinnitus is a significant cause of stress, and those affected by tinnitus may react differently depending on their vulnerability to stress. Tinnitus sufferers may have a particular vulnerability to the stress impact of the tinnitus sound.Reference Malakouti, Nojomi, Mahmoudian and Salehi6 Vulnerability to stress could be genetic, and there could be a shared neurobiological pathway influencing the development of both depression and tinnitus.Reference Malakouti, Nojomi, Mahmoudian and Salehi6, Reference Zoger, Svedlund and Holgers10 Co-morbid mental disorders are likely to be the most important factors affecting the disability and suffering of tinnitus patients, as indicated by the articles described in this review.Reference Zoger, Svedlund and Holgers10 Besides coexisting psychiatric disorders, only tinnitus intensity seems to significantly contribute to tinnitus-related annoyance. Degree of hearing loss does not seem to correlate with tinnitus severity, as evaluated by the Tinnitus Handicap Inventory.Reference Pinto, Sanchez and Tomita30 A vicious cycle is usually established in tinnitus patients: tinnitus causes and exacerbates stress, and stress causes and worsens tinnitus. Tinnitus may not always be the starting point of this cycle. Many tinnitus patients have experienced a certain degree of anxiety and depression prior to the onset of the symptom. However, tinnitus can increase the severity of existing psychological disorders or tendencies.Reference Folmer, Griest and Martin16 Hence, tinnitus can cause or be caused by psychiatric disorders, and it is often difficult to know what came first. When tinnitus and psychiatric disorders coexist, both conditions should be treated in order to achieve the best results in terms of patients' quality of life.
Placebos appear to have a strong effect on tinnitus; nearly 40 per cent of tinnitus patients treated with a placebo showed improvement in tinnitus-related quality of life.Reference Dobie, Sakai, Sullivan, Katon and Russo31 This supports the important modulatory role that psychological factors have in shaping perceptions of tinnitus and increasing the associated distress.
In the early 1990s, Jastreboff and Hazell reported on the major role of abnormal activation in the limbic system and autonomic nervous system in patients who were annoyed and often completely handicapped by tinnitus.Reference Jastreboff and Hazell2 This role reflects the mechanism underlying the difference between the 80 per cent of patients who only experience tinnitus and the 20 per cent who suffer from tinnitus. Again, the relationship between tinnitus and emotions is well described.
Currently, most work with tinnitus patients is based on a multidisciplinary approach, with collaboration between the otolaryngologist, the audiologist and mental health professionals.
The studies described vary greatly in terms of the instruments used to assess the impact that tinnitus has on patients' lives and to evaluate psychiatric diagnoses and symptoms. This variation could interfere with comparisons between the studies. Moreover, certain instruments used in psychiatric evaluation can determine a psychiatric diagnosis, whereas others demonstrate only the presence of psychiatric symptoms. In our opinion, although the Structured Clinical Interview is the ‘gold standard’, the Mini International Neuropsychiatric Interview could be a good tool as this instrument determines a psychiatric diagnosis and is an easy scale to be trained on. When evaluating the impact that tinnitus has on a patient's life, the Tinnitus Handicap Inventory is the questionnaire recommended by the Tinnitus Research Initiative because this instrument has been translated into the greatest number of languages.
Conclusion
After evaluating the reviewed articles, we conclude that the prevalence of psychiatric disorders, especially anxiety and depression, is high in tinnitus patients. Furthermore, the presence of these disorders correlates with tinnitus severity and tinnitus-related annoyance, impacting further on patients' quality of life.
