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Interview in Medscape – Language patterns may help diagnose depression

BARCELONA, Spain ― Distorted language structure may help clinicians diagnose mild depression and distinguish between the disorder and “normal sadness,” new research suggests.

A study of 201 individuals who were asked to write a short essay showed that those who had mild depression used more total words, more narration than reasoning, more ellipsis, more repetitions, more self-centered speech, and more verbs in the past tense in their text than did their healthy peers. They also used simpler sentences.

Participants who reported normal sadness showed many of these same patterns, but they also used more present tense verbs and wrote more about altruism, self-realization, and social status than did those with clinical depression.

“It’s important to not only look at a patient’s complaints but also to look at how that information is presented,” lead author Daria Smirnova, MD, PhD, assistant professor in the Psychiatry Department at Samara State Medical University in Russia, told Medscape Medical News.

“Clinicians should look at written self-reports from their patients and see what key words are being used in the text and what semantic topics are presented, or they can also use this information when conducting structural clinical interviews,” added Dr. Smirnova.

The study was presented here at the 26th European College of Neuropsychopharmacology (ECNP) Congress.

Not Just What Patients Say but How They Say It

According to the investigators, depression rates have increased from 0.4% to 0.8% in the 19th century to approximately 5% to 10% today, with the increase mostly coming from minor forms of the disorder.

In addition, there is a 50% median rate of untreated depression worldwide, according to the World Health Organization.

“High rates of depression are viewed by many, both within and outside the psychiatric field, with some degree of skepticism due to the issue of validity and reliability of psychiatric diagnoses,” write the researchers, noting that difficulties are often found in differentiating between mild depression and ordinary sadness.

Dr. Smirnova added that “there are a lot of data” showing that language plays a part in many psychiatric disorders ― but just a few studies have looked at the clinical aspects of this.

“It’s been said that psychosis is the price that Homo sapiens pay for language in the process of evolution,” she said.

“We’ve found that it is very important to take into account not only what a patient says but also how the patient speaks.”

For this study, the investigators enrolled 124 patients (67% women; mean age, 41.9 years) who had been clinically diagnosed with mild depression in Russia. All were placed into subgroups on the basis of the following subtypes of depression: anxious (n = 45), asthenic-hypodynamic (n = 41), or melancholic (n = 38).

In addition, 77 “healthy control” participants (79% women) were included. Of these, 35 (45% women) reported reactions of normal sadness related to psychosocial or socioeconomic circumstances.

Features of superficial and deep levels of written speech were assessed in 201 self-reports from all participants on the theme of “the current state of life.”

Several psycholinguistic procedures were used to measure speech patterns, including “descriptive methodics, nonparametric analysis, and mathematic modelling of discriminate analysis.”

Depressed Patients More Verbose

Results showed that the writings from patients with depression were found to be more verbose than were those from the healthy control participants (311.18 words vs 197.25 words, respectively). They also showed more narrative organization than organization based on reasoning (85.5% vs 14.5%, respectively).

In addition, the group with depression showed more communicative discourse than did the healthy control group (100% vs 11.69%), as well as more use of ellipsis and conversational constructs, such as phraseologisms and lexical and semantic repetitions.

“Lexical-grammar sublevel was impoverished in meanings by increased number of pronouns, in particular the personal type (self-centered speech),” report the investigators.

Interestingly, 100% of the depressed group used verbs in the past tense compared with just 2.6% of the healthy control group. Also, they used more simple sentences (79.8% vs 2.6%, respectively) and almost always inverted word orders (99% vs 6.49%, respectively).

The top category written about in both groups was existential (mentioned by 100% of the depressed group vs 84.4% of the healthy control group) and family (91.1% vs 76.6%, respectively).

The depressed group also wrote more about “communicative” and “hedonic” issues than they did about self-realization or social status topics.

When comparing the 2 subgroups within the healthy control group, those with normal sadness also showed more use of ellipsis and lexical and semantic repetitions than did those not reporting any sadness.

However, the subgroup with normal sadness used verbs in the present tense more than did the other subgroup.

Language Differences

“Those with depression used more past tense verbs, and those with normal sadness used more present tense verbs. But neither group used the future tense much,” said Dr. Smirnova.

“Mathematical modelling proved the importance and significance of verbal markers for diagnostics and differentiation of subtypes of mild depression and normal sadness (P < .001),” write the investigators.

The subgroup with normal sadness had a much higher frequency of writing about cognitive, social status, self-realization, and altruistic categories within their texts than did the overall group with depression.

Although speech distortions in structure and semantics were found in both those with mild depression and those with normal sadness, the most pronounced language disturbances of all, especially in deep semantic structures, were found in the melancholic depression subgroup.

Those in the asthenic-hypodynamic subgroup showed more damage in superficial levels of speech. They maintained an overall coherence in their written reports, but also left out important words and facts.

On the other hand, the patients with anxious depression used complex sentences and showed a coherence of facts and of reasoning that was similar to the non-sad healthy control subgroup.

Still, “mild depression and state of normal sadness are characterized by definite psycholinguistic features which reflect cognitive dysfunction and thought strategies significantly related to the symptoms of leading hypothymic affect and signs of mood deviation,” write the researchers.

Helpful Diagnostic Tool

“This study is very interesting because it talks about the increase in communicative writing and talk in patients with clinical depression, which is something I have observed,” Pierrette Estingoy, MD, a psychiatrist and teacher at the Medical University of Lyon 1 in France, told Medscape Medical News.

“Yet altruistic talk and self-realization are very low in this population. And that’s also something I have seen,” she said.

Dr. Estingoy, who was not involved with the research, noted that the findings could be useful for clinicians during the diagnostic process.

“It could be helpful. I just found this very, very interesting for me as a doctor,” she concluded.

The study authors have disclosed no relevant financial relationships.

26th European College of Neuropsychopharmacology (ENCP) Congress. Abstract P.2.b.060. Presented October 6, 2013.