Journal of Geriatric Mental Health

REVIEW ARTICLE
Year
: 2020  |  Volume : 7  |  Issue : 1  |  Page : 11--20

Depression and somatic symptoms in dementia: A narrative review


Shiva Shanker Reddy Mukku, Geetha Desai, Santosh K Chaturvedi 
 Department of Psychiatry, NIMHANS, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Shiva Shanker Reddy Mukku
Department of Psychiatry, NIMHANS, Bengaluru, Karnataka
India

Abstract

Dementia is an irreversible progressive degenerative disease with cognitive impairment. Cognitive impairment eventually leads to impaired activities of daily living and premature mortality. Apart from cognitive symptoms, nearly two-thirds of dementia patients have behavioral problems commonly known as behavioral and psychological symptoms of dementia (BPSDs). Depression and dementia have a complex relationship. Depression is a risk factor, prodrome and as well as a BPSD symptom in dementia. Depression in dementia is known to cause decreased quality of life and poor outcomes. Depression though common in dementia it is often under-recognized and treated. Somatic symptoms are further less studied BPSD in dementia. With the changes in nosology and criteria for somatic symptoms disorders in the classificatory system, there is renewed interest in somatic symptoms in dementia. In this article, we discuss about depressive and somatic symptoms in patients with dementia along with assessment and management.



How to cite this article:
Reddy Mukku SS, Desai G, Chaturvedi SK. Depression and somatic symptoms in dementia: A narrative review.J Geriatr Ment Health 2020;7:11-20


How to cite this URL:
Reddy Mukku SS, Desai G, Chaturvedi SK. Depression and somatic symptoms in dementia: A narrative review. J Geriatr Ment Health [serial online] 2020 [cited 2020 Aug 13 ];7:11-20
Available from: http://www.jgmh.org/text.asp?2020/7/1/11/288239


Full Text



 Introduction



Dementia is a progressive neurodegenerative condition commonly presenting in late life. Dementia causes progressive cognitive decline and ultimately leads to dependency for activities of daily living.[1] Apart from cognitive symptoms, dementia patients have behavioral problems commonly termed as behavioral and psychological symptoms of dementia (BPSDs). BPSDs are one of the most distressing symptoms of dementia. Often, BPSDs are the reason for caregiver distress and early institutionalization.[2],[3] BPSDs commonly include apathy, depression, agitation, psychotic symptoms, sleep disturbances, emotional lability, somatic symptoms, and disinhibition.[4] Depression is one of the common BPSDs associated with dementia. Nearly 80% of dementia patients have depressive symptoms over a course of 5 years. In that 10%–20% of patients present with a major depressive disorder.[5] The relation between depression and dementia is well known.[6] Depression presenting in mid-life or late life is a known risk factor for dementia.[7],[8] Depression can present as prodrome of dementia in late-life [9] or it could be one of the BPSDs in an established dementia.[10] Depression in dementing illness is known to have a bearing on the course and quality of life of a patient.[11],[12] Though depression is common in patients with dementia, it is often underrecognized and treated. This is due to various barriers associated with health professionals as well as caregivers of dementia.

Another less studied BPSDs seen in dementia patients are somatic or bodily symptoms or somatization. These symptoms include headache, sensory and pain symptoms, gastrointestinal symptoms, and fatigue.[13],[14] These symptoms are associated with excess somatic preoccupation and distress. Somatization is traditionally considered as nonspecific physical symptoms that persist despite the absence of medical illness.[15] The recent classificatory system have changed the understanding of somatization, that it can be diagnosed even in the presence of medical illness if the preoccupation and distress is excess than expected in the individual.[16] The available literature considering the prevalence of somatization in dementia patients is still emerging. Somatization is considered an expression or idiom of distress presenting in the form of physical symptoms.[17] In continuation of the above, the concept of alexithymia, which means unable to express one's feeling remerged. Studies have reported on the association between alexithymia and somatic symptoms.[18] In case of neurodegenerative conditions presenting with somatization, apart from the psychological explanations, there are also evolving neurobiological processes happening in the brain as a part of the illness. In this way, dementia might provide further insights into the neurobiological understanding of somatoform disorder. From the above prelude, it is clear that comorbid depression and somatization in dementia play an important role in the outcome and quality of life in these patients. The objective of this article is to discuss about depression and somatization in patients with dementia along with recent advances in evaluation and management.

 Methods



The articles related to dementia, somatic symptoms, and depression were searched in PUBMED and GOOGLE SCHOLAR websites. A search using terms “Dementia” combining with other terms “depression,” “assessment of depression,” “Evaluation of depression” and “Management,” “somatisation,” “Somatic symptoms,” “vague pain symptoms.” We have chosen the articles related to the topic that are published in the English language.

 Depression in Dementia



Dementia and depression in the elderly are the important causes of morbidity and mortality in late life. There is a complex relation between depression and dementia. As it was discussed earlier depression is a proven risk factor for dementia, it could be a prodrome of dementia when it occurs in late life or it can be a BPSD.[6],[19] In the recent Lancet Commission on dementia, depression contributes to 4% out of 35% total potential modifiable risk factors.[20] There is also overlap in clinical features and to certain extant shared genetics such as ApoE4 allele.[21],[22],[23] Depression is one of the most common behavioral symptoms in dementia. Studies have reported depression further reduces the quality of life in patients with dementia.[24],[25] Here, we discuss the prevalence, neurobiology, evaluation, and management of depression in dementia.

 Prevalence of Depressive Symptoms in Dementia



Depression/depressive symptoms are highly prevalent psychiatric morbidity in dementia. In a study done on 98 patients with Alzheimer's dementia (AD)/vascular dementia (VaD) attending psychiatry unit in Moscow, the prevalence of depression was 87% using DSM-IV criteria and Geriatric Depression Scale (GDS).[24] The prevalence of depression in dementia from low- and middle-income countries from the 10/66 study data was 12.4%.[26] In the 10/66 study depression was assessed using Geriatric mental status examination. Compared with Alzheimer's disease (AD), diffuse lewy body dementia (DLBD) (odds ratio [OR]: 2.75 [95% confidence interval [CI]: 1.40–3.72]) and VaD (OR: 2.35, [95% CI: 1.49–3.72]) were associated with a higher risk of depression.[26] In a meta-analysis done in 2015 which included 63 studies reported 12.7% as prevalence of depression in dementia as per DSM-IV criteria and 42% using specific instruments in dementia.[27] The Cache County Study reported a 30-day prevalence of depressive symptoms in 29.9% of participants with dementia and in 16.9% of participants with cognitive impairment that did not meet criteria for dementia, and 4.9% in cognitively normal individuals.[28] The prevalence of depression in the elderly without dementia from two studies with larger samples conducted in rural part of north India and south India were 7.5% and 12.7%, respectively.[29],[30] A recent meta-analysis reported the prevalence of depression in elderly from published Indian studies as 34.4%.[31] The prevalence of depression in dementia is higher compared to that in the elderly without dementia from the available literature. However, there were no comparative studies from India. The variability in the prevalence of depression in dementia across the studies could be due to differences in the instrument used for assessing depression, setting, severity, and type of dementia. Depression is also relatively persistent in dementia, as several studies have shown about half of dementia patients with depression remain depressed even after 1 year.[32]

 Etiology of Depression in Dementia



The causes of depressive symptoms in dementia can be understood by classifying into two broad categories viz., psychological and biological. The psychological factors contribute especially in earlier stages of dementia for depression. In the initial stages of mild cognitive impairment and mild dementia, patients have cognitive decline but are able to perform usual activities. In this stage, factors that contribute for depression are becoming consciously aware of cognitive decline, reduced: functional ability, excessive worry about their own health, preoccupation about their role, anxiety due to word-finding difficulty, difficulty in recalling names of relatives in social gatherings and stigma. The collusion that often exists between the families and physicians under the premise that patient does not remember the information shared also creates anxiety in the patients.[33]

The structures involved in the regulation of emotions and mood are the prefrontal cortex and limbic structure.[34] The prefrontal structures more specifically dorsolateral and ventromedial areas are known to be implicated in producing depression.[35] Along with above said structures, the corticostriatal circuits connecting the prefrontal basal ganglia and limbic structures are the networks regulating the mood and behavior.[36] Any condition that causes disruption of these circuits leads to depression. Dementia being a neurodegenerative condition causes disruption of corticostriatal circuits and affect prefrontal regions thus increases the risk for depression.[37],[38] In VaD, the involvement of subcortical structures and deep white matter are implicated in depression.[39],[40] Another important factor that increases the risk of depression in dementia is the involvement of the serotonergic system. In AD and synucleopathies (Parkinson's disease [PD], DLBD), the degenerative process involves raphe nucleus is and implicated in the loss of serotonergic neurons.[41] There is also evidence from postmortem studies of patients with dementia which report decreased levels of serotonin and its metabolite 5-hydroxyindoleacetic acid in cerebrospinal fluid and cortex.[42],[43] A study on postmortem brain sample of AD patients compared the neurotic plaques (NPs) and neurofibrillary tangles (NTs) and Geriatric Depression Scores (GDS). The study reported no association of GDS scores with NP and NF in patients with AD.[44]

 Risk Factors for Depression in Dementia



Reported risk factors for depression in dementia include earlier age at onset of dementia, female gender, lower education, previous history of depression, greater severity of neuropsychiatric symptoms, benzodiazepine use, history of transient ischemic attack and recent losses.[44],[45],[46] Psychosocial factors such as financial burden, dependency, change in the family setup and poor social support increase the risk of anxiety and depression in patients with dementia.[47] However, factors such as the severity of cognitive impairment, insight, NPs, and NTs are poorly correlated with depression in dementia.[44],[45],[48],[49]

 Impact of Depression on Dementia



In a patient with a dementing illness, comorbid depression has severe repercussion in the course and quality of life. Depression increases inactiveness, lead to decreased physical activity, poor sleep and decreased appetite. During depression, patients may not comply with routine activities, regular medication, and physician consultations. All these will lead to further cognitive decline and progression of illness. Depression decreases the quality of life of a patient and increases mortality.[12] This also lead to increase in the caregiver burden and distress in them.[50] More serious consequences of depression in dementia many include refusal of food and suicidal attempts. All these issues in a patient with dementia and comorbid depression will increase morbidity and early institutionalization.[51],[52] There is also increased health-care utilization and family burden.[53],[54]

 Bidirectional Relationship between Depression and Dementia



Depression and dementia are two mental illnesses that are commonly seen in the elderly. Depression and dementia manifest at different time points in life which is the common scenario or depression can present as a prodrome of dementia or coexist together. Apart from higher dual existence in the elderly, they also increase the risk of each other. Several retrospective and prospective studies (Framingham Heart Study, Rotterdam Scan Study, Women's Health Initiative Memory Study) have reported that depression irrespective of the age of onset increases the risk for dementia.[7],[19],[55],[56] There are reports that besides depression being a risk factor for dementia, it can be an early symptom or prodrome of dementia.[9],[57] Few neurobiological hypothesis have been put forward regarding this, such as glucocorticoid neurotoxicity, comorbid cerebral vascular disease, higher prevalence of Apoε 4 in elderly with depression which are known risk factors for dementia.[58],[59],[60]

 Evaluation



It is a standard practice for patients presenting with depressive illness in late life to screen and evaluate for cognitive impairment and dementia. Similarly, in patients with established dementia, screening, and enquiry for depressive symptoms are advised at every patient visit. It is not as straight forward to diagnose depression in dementia as in healthy young individuals. There are few challenges in diagnosing depression in dementia such as patient inability to comprehend the physician words, unable to express due to word-finding difficulty and hearing and visual impairment in elderly are other issues that compound the matters further during the psychiatric interview. All these could lead to interviewing the caregivers and getting circumstantial evidence about the patient's well-being and psychological issues. This might not give accurate information all the time. Sometimes if caregivers are not keen observers, it leads to underreporting and missing the depression.[61] There is also an overlap of certain symptoms such as apathy, poor concentration and sleep/appetite changes which can occur in depression as well as dementia. These symptoms may often be overlooked thus under recognizing the depression.[62]

Here are a few pointers that could be useful in routine clinical practice to diagnose depression in dementia. Depression in dementia patient should be suspected if there is (1) unexplained acute cognitive worsening from the previous level of functioning; (2) if there are new behavioral problems such as agitation, withdrawn behavior, decreased spontaneous speech and decreased sleep at night, decreased food intake and uncooperativeness for routine activities; and (3) symptoms such as anxiety, loss of energy, irritability, delusions and hallucinations may all be are more common in depression with dementia. All these should be enquired with caregivers or staff of residential care facility during the physician visit. Always spend time with the patient to get his perspective on depressive symptoms. Observation of patient behavior will also reveal signs of depression such as psychomotor retardation or agitation, crying spells and appearing withdrawn. It is advisable to review patients and reach a diagnosis on prospective observation than cross-sectional examination especially when one suspect medico-legal issues. Few standard scales are recommended for use to screen for depression in dementia.[62],[63] One of the popular and widely used scales is the GDS.[64] It is a self-rated 30 item rated on binary response (yes or no) scale. It is a validated tool to screen depression in the elderly. The shortened 15 item version is more frequently used in the clinical setting. A score above 5 indicate possible depression and score above 10 more probable depression. Another scale used to screen depression in moderate to severe stage of dementia is Cornell scale for depression in dementia (CSDD).[65] It is a 19 item scale, scored from the informant interview about the patient and direct observation of the patient. Each item is rated for severity on a scale of 0–2 (0 = absent, 1 = mild or intermittent, and 2 = severe). Scores above 10 indicate a probable major depression. Scores above 18 indicate a definite major depression. These two scales are useful in busy clinics to find elderly patients who are likely to have underlying depression thus they can be interviewed further for clinical diagnosis. In patients in whom depression is not evident from single consultation, regular follow-up is suggested. In patients with severe depression expressing suicidal ideas or suicidal attempts needs to be admitted to a safer place for further intensive management. It is advisable to review the medical history and medication to prevent any drug interactions.

 Management



Nonpharmacological interventions

The nonpharmacological intervention should be the first line of treatment in the management of depression in dementia especially when the severity of depression is mild to moderate. These interventions could be as simple as initiating daily physical activities to start with. Physical activities/exercises have been found to be effective in reducing depressive symptoms along with multiple physical benefits.[66] Reminiscence therapy using patients old pictures, videos, personal objects and making patients to connect to the past events and promote a positive mood in them is another method.[67] Another behavioral intervention by Lewisohn's based on 'Pleasant Events model' known as behavioral programming. This model is based on the assumption that a person's behavior is related to how he or she feels. This technique involves identifying pleasant and negative events in the patient's daily life.[68] This model along with physical exercise has been evaluated in AD patients and found to have a positive effect in depression.[69] Cognitive behavioral therapy targeting the negative automatic thoughts and cognitive distortion could be useful in mild stage of dementia.[70],[71] Another behavioral intervention that has been studied is problem solving therapy.[72],[73] It was found to be effective for caregivers of dementia.[74] Few other innovative interventions such as art therapy,[75] animal-assisted therapy,[76] music therapy,[77],[78] and multisensory stimulation (snoezelen)[79] can be tried in certain patients but these are not well studied in the Indian setting. Aromatherapy and massage/touch therapy has been tried with a positive effect on agitation in patients with dementia, but, there is limited evidence for depression.[80],[81] Though nonpharmacological interventions are useful and should be tried first especially in mild to moderate severity of depression there are certain limitations. First is the patient's cooperativeness and acceptability of these interventions. Another important limitation is the time that needs to be spent by caregivers or paid professionals with patients. It is a major challenge in low- and middle-income countries, where the care is provided by mostly informal (family members). The last limitation is many of these interventions we have discussed were not been vigorously tested in methodologically proven ways.

Pharmacotherapy

Pharmacological interventions should be considered if psychological/behavioral interventions have not resulted in an optimal response or not feasible in patients with dementia. Medication can be tried in severe depression either alone or along with psychological interventions wherever feasible. The response to medication in patients with dementia is suboptimal compared to the younger population. The reasons include elderly age, higher medical comorbidities which will alter the pharmacokinetics and pharmacodynamics of the psychotropics. Medical comorbidities often limit reaching a therapeutic dose leading to low response rates. The degenerative condition itself causes changes in brain microenvironment leading to treatment-resistance. There are relatively less vigorous methodological studies on use of antidepressants in dementia. There is a low to moderate level of evidence for medication in the treatment of dementia with depression. Guidelines for the management of BPSD in dementia formulated by National Institute for Health and Care Excellence,[82] American Psychiatric Association guidelines,[83] Australian guidelines for depression in dementia [84] and Clinical Practice Guidelines-Indian Psychiatric Society [85] are recommended.

Antidepressants in depression

Antidepressants are broadly classified into tricyclic antidepressants (TCA), selective serotonin reuptake inhibitors (SSRIs) and newer antidepressants such as mirtazapine, bupropion venlafaxine etc., Many of these drugs have been studied in dementia patients with dementia with comorbid depression. The evidence for antidepressants in dementia with depression found only modest effect which was not statistically significant compared to placebo.[86],[87] SSRIs are the preferred first choice of medication followed by mirtazapine and trazodone.[88] Concerns with SSRI in the elderly include sedation, risk of falls, osteoporosis, fractures, hyponatremia, and risk of gastrointestinal (GIT) bleeding. Any elderly patient who requires SSRI trial needs to be investigated thoroughly with blood investigation (serum electrolytes, RFT, LFT, and FBS), electrocardiogram, and history of GIT bleeding and falls. Antidepressants should be titrated slowly to their effective dose, monitoring simultaneously for adverse effects periodically. TCAs are preferably be avoided in patients with dementia due to their higher cardiotoxicity and anticholinergic burden.[89]

Acetylcholinesterase inhibitors and memantine

Cholinesterase inhibitors and memantine are commonly prescribed medication in AD. These drugs are known to preserve the functioning for longer duration and delay the time to institutionalization. Limited studies that have looked at the effect of Acetylcholinesterase inhibitor (ACEI) and memantine on BPSD found their usefulness.[90],[91] Though depression was not specifically studied, there was reduction in behavioral problems and neuropsychiatry inventory scores with ACEI.[92],[93],[94]

Anticonvulsants

Valproate, carbamazepine and lamotrigine have been used for behavioral problems with modest efficacy.[95],[96] There are studies that found decreased GABA level in cortical regions and hypothesized to have a causative role in BPSD.[97] Anticonvulsants by increasing the GABA level were proposed to be helpful in BPSD. There is little direct evidence for anticonvulsants for depression in dementia. These can be used after the failed trial of SSRI and other newer antidepressants.

Brain stimulation methods

Electroconvulsive therapy (ECT) is a proven and effective treatment for depression in cognitively healthy patients. ECT was investigated as a treatment for depression in dementia in few studies. The studies have shown positive results in studies on dementia with depression.[98] The risk of worsening of cognitive symptoms such as post-ECT confusion, the presence of medical comorbidities often limits its acceptability in elderly and even more so in patients with dementia.[99] There is recent emerging evidence on the tolerability of ECT in patients with dementia for various indications.[98],[100] At this point, ECT can be considered as an option when other treatment methods fail in moderate to severe dementia patients. Pre-ECT evaluation for fitness, education of family members, and monitoring for any cognitive worsening regularly after ECT will ensure safe and effective use of ECT.[101] Repetitive transcranial magnetic stimulation (rTMS) has been tried in patients with AD primarily for cognitive symptoms.[102] In two studies involving smaller samples, rTMS led to improvement in comorbid depression in patients with AD.[103],[104] Transcranial direct current stimulation (tDCS) is another noninvasive modality with literature limited to its usefulness for apathy in dementia. There is an ongoing randomized controlled trial evaluating the effectiveness of tDCS for depression in dementia.[105]

 Somatic Symptoms in Dementia



The 1-year prevalence rate of somatoform disorders in the elderly in the community is 3.8% compared to 11%–20% in a younger individual.[106],[107] Most studies reported low prevalence of somatoform disorders in late life. This is due to various limitations in the methodology of the studies along with difficulties in assessing elderly for somatoform disorders. Elderly patients often have comorbid medical illnesses that are known to cause pain and other physical symptoms. They generally present to a physician with these complaints rather than to mental health professionals, thus leading to less enquiry and recognition of somatoform in elderly.[108] As per the ICD-10 diagnostic criteria, somatization disorder is defined as the presence of vague, multiple physical symptoms for at least 2 years with excessive preoccupation and distress. These symptoms should not be explained by any other medical condition.[15] After two decades these criteria were changed in DSM-5, and the condition is called somatic symptom disorder. It is now defined as a condition with persistent somatic symptoms that are accompanied by abnormal thoughts, feelings and behaviors. Another major change from ICD-10 was somatic symptom disorder can be diagnosed even in the presence of the medical condition.[109] There is well-established evidence for the occurrence of somatic symptoms as individual symptoms or as comorbid condition in depressive disorders and anxiety disorders in the elderly. Somatic symptoms are considered to represent psychological distress presenting as physical symptoms. The underlying concept which explains the presence of somatic symptoms is alexithymia. Alexithymia is an enduring characteristic trait in which a person is unable to express his emotions due to genetic and environmental factors.[110] There are reports on the occurrence of somatic symptoms in neurodegenerative condition such as dementia. More than half a century ago, Robertson published detailed clinical descriptions of 3 cases with Pick's disease where somatic complaints and generalized hyperalgesia were the prominent clinical symptoms.[111] This is followed by Gustafson who made similar observations in frontotemporal dementia (FTD) and possible neuroanatomical structures involved.[112]

 Prevalence of Somatic Symptoms in Dementia



There were few studies that have evaluated the prevalence of somatic symptoms along with other behavioral problems in dementia. One of the initial studies by Bathgate et al. compared the prevalence of somatic symptoms in FTD, AD and VaD using a semi-structured questionnaire. The study found the somatic symptoms in the form of hyperalgesia was 33% in FTD, 42% in AD and 26% VaD.[113] Another cross-sectional study by Chan et al., reported somatic symptoms in 35% FTD patients with right predominant temporal lobe atrophy.[114] A larger retrospective study by Landqvist Wald et al. in 97 FTD patients reported somatic symptoms in 40.2%. The study also compared the relation between somatic symptoms in tau-positive and tau-negative FTD patients. However, no significant correlation was found between various pathological types and somatic symptoms.[13] The latest study on somatic symptoms by Gan et al. compared the prevalence of somatic symptoms in semantic dementia and AD. The prevalence was higher in Semantic dementia (SD) (41.5%) compared to AD (11.2%) with an odd ratio of 6:1. The common symptoms were misidentification, preoccupation with normal bodily sensation such as hunger, bladder filling, borborygmi, rhinorrhea, and reflux.[115] Among the very few prospective studies, the one by Onofrij et al. compared prevalence of somatic symptoms in PD with other degenerative conditions (DLBD, AD, FTD, Progressive Supranuclear Palsy [PSP], and Multisystem Atrophy [MSA]). The study found prevalence of 7% in PD, 12% in DLBD, 1% in AD, 2.5% in PSP and 0% in FTD and MSA. Within the diagnostic groups, there was a difference between those with somatic symptoms and those without in demographic and clinical features.[116] However, in patients with PD, the cognitive decline was higher in those with somatic symptoms.[116] In elderly without dementia a study from north India using “Schedule for Clinical Assessment in Neuropsychiatry” reported prevalence of somatization as <2%.[29] Similar study from south India using “Patient Health Questionnaire-15” reported somatization in 40% of the elderly.[117] The frequency of somatization is higher in dementia compared to the elderly without dementia, but there is heterogeneity among the studies. Few limitations of these studies such as most of them being cross-sectional or retrospective in nature, hospital-based and no structured assessment used in most studies, which limits the generalizability of the results [Table 1].{Table 1}

 Neurobiological Aspects of Somatization in Dementia



Patients with somatoform disorder are thought to have certain abnormalities in the sensory processing in the brain. These patients often exhibit a heightened focus on their own bodies, perceiving their bodily complaints quicker as illness than healthy people do.[118] Central sensitization is another concept that has recently been used to describe a neurobiological abnormality. According to this concept, it is assumed that somatic symptom onset is associated with a hyper-responsive neural network. Patients with somatization are also known to rate normally innocuous stimuli as painful stimulation due to an alteration of the central network.[119] A meta-analysis of 10 studies reported major differences in the premotor and supplementary motor cortex, middle frontal gyrus, anterior cingulate cortex, insula and posterior cingulate cortex in somatoform disorder patients compared to healthy individuals.[120] Similar to these findings, somatization in dementia could also be due to abnormalities in central pain processing networks.[121],[122] Studies have reported somatic symptoms more commonly in semantic FTD and behavioral variant FTD and to a lesser extent in AD.[113] FTD formed a prototype in understanding the origin of somatic symptoms in dementia. The initial finding reported that midline frontal and anterior cingulate which are part of pain processing are affected in FTD.[123] This could be one reason for somatization in FTD. Later studies using neuroimaging in FTD patients with somatic symptoms revealed grey matter loss in posterior thalamus, posterior insula and anterior temporal cortex. These areas are known to be part of central pain processing. In the case of SD, there is another perspective for somatization. It is known that in SD there is loss of object knowledge, single-word comprehension with relatively spared episodic memory. Apart from the inability to make meaning of the external world, they have difficulty in interpreting normal physiological sensation described as “alexisomia”. This leads to excessive preoccupation and misinterpreting these stimuli which manifest as somatic symptoms.[115] There is also a genetic basis to the somatic symptoms in FTD particularly those with C9ORF72 mutations reported to have a higher rate of somatic symptoms.[124] It is well known that somatization is often associated with depression and anxiety, but contrary to this, study by Landqvist Wald et al. found no such association.[13]

 Challenges in the Evaluation of Somatic Symptoms in Elderly and Dementia



Evaluation of somatic symptoms in the elderly is challenging. To begin with, late life is associated with increased prevalence of medical and surgical conditions. Conditions such as osteoarthritis, peripheral neuropathy, osteoporosis, tumors, diabetes, ischemic heart disease and their complications are well known to cause pain and other physical symptoms. These are difficult to differentiate from somatoform disorder in routine consultation with a physician.[125] The somatic symptoms are often treated as physical condition and treated in that manner. There is also a tendency for physicians to overlook the diagnosis of somatoform in elderly compared to that in the younger patients. Another challenge faced among the elderly is excessive worry regarding their physical changes associated with ageing and health-related issues. The preoccupation about their health, associated safety measures and frequent physician consultations will make them more likely receive a diagnosis of anxiety disorder or depression than a somatoform disorder.[108] Further, lack of office-based and easy to use screening tools also lead to under-recognition of this disorder. In the case of dementia, the issues are even more complex. The cognitive impairment in dementia become a major barrier in interviewing the patients. In a patient with dementia cognitive impairment, medical comorbidity and disruptive behavioral problems are the major issues for caregivers and physicians. In these scenarios, somatic symptoms are overlooked and often never get evaluated.

 Instruments to Assess Somatic Symptoms in Elderly



There are many instruments for assessing somatic symptoms with only few studied in the elderly population. Somatic Symptom Index is one of the earliest scales for identifying somatoform disorder. It has 35 items and validated in many epidemiological studies.[126] Brief Symptom Screen is a self-rated 10 item scale developed for elderly people. Symptoms included are shortness of breath, feeling tired or fatigued, problems with balance or dizziness, perceived weakness in legs, constipation, daily pain, stiffness, poor appetite, anxiety, and anhedonia.[127] Patient Health Questionnaire (PHQ-15) is a self-administered somatic symptoms subscale, derived from the full Patient Health Questionnaire. PHQ-15 specifically assesses somatic symptom severity and the potential presence of somatization and somatoform disorder. The PHQ-15 has good reliability, construct, and criterion validity.[128] Few other instruments include Scale for Assessment of Somatic Symptoms,[129] Subjective Health Complaints Inventory,[130] and Somatic Symptom Scale-8.[131] Details regarding these instruments are given in [Table 2].{Table 2}

 Conclusion



BPSD is an important symptom domain which determines the quality of life and caregiver burden in dementia care. BPSD presenting as depression and somatization are often underdiagnosed and undertreated. Depression has a unique relation with dementia in terms of shared risk factors, shared genetics and few symptom overlap. These features make identifying depression in dementia a diagnostic challenge. Collateral information from multiple caregivers, behavioral observation and using appropriate standard scales helps in early identification of depression in dementia. The management of depression in dementia should always begin with behavioral and psychological interventions. In a situation where behavioral interventions are not feasible or not effective, medication should be considered. Antidepressants should be considered only after weighing the risk and benefits or as a first choice in those with severe depression. The effectiveness of antidepressants in dementia with depression is poor in randomized control trails. ECT can be considered in refractory depression in patients with dementia or in whom medication has caused significant adverse effects. Somatic symptoms/somatization in dementia are less explored domain compared to other BPSDs. They are commonly reported in FTD and its variants. There is emerging literature of neurobiology of somatic symptoms in SD. Somatization further needs to be investigated in other subtypes of dementia.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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