The relationship between disease symptoms and restless legs syndrome in adult attention-deficit hyperactivity disorder without iron deficiency – Middle East Current Psychiatry

Study sample

The study was carried out in the Hitit University Erol Olçok Training and Research Hospital, Department of Psychiatry. This prospective study was approved by the Hitit University Clinical Research Ethics Committee.

The study sample consisted of 120 drug-naive adult ADHD individuals. The criteria to be included in the study were being over 18 years of age, under 65 years of age, and literate, agreeing to participate in the study, and meeting the criteria for adult ADHD diagnosis for the patient group. In the patient group, those with other disorders that could cause secondary restless leg syndrome, such as iron deficiency, anemia, kidney dysfunction, diabetes mellitus, multiple sclerosis, rheumatological diseases, hypertension, any metabolic disease, epilepsy, stroke, and malignant diseases, were excluded from the study. In order to exclude iron deficiency and anemia, we included those with a ferritin level of 30 ng/mL and above, a hemoglobin value of 12 g/dl and above in women, and 13 g/dl and above in men, according to complete blood count values. Also, the study excluded those with psychotic disorder/mood disorder with psychotic characteristics, mental retardation, alcohol, and substance use disorder, and those using antipsychotic drugs and stimulants.

After the subjects who met the inclusion criteria were informed about the research, those who accepted to participate in the study signed the Informed Volunteer Consent Form. Then, a diagnostic interview for attention-deficit/hyperactivity disorder (DIVA) was applied to the patient group by the researcher in the study. The age of onset of the disease and the number of symptoms were determined according to the DSM-5 diagnostic criteria. ADHD subgroups were determined according to DIVA. Adult ADHD patients were divided into two as predominantly inattentive ADHD type (ADHD-I) and the combined type, in which hyperactivity, impulsivity, and attention deficiency co-exist (ADHD-C). Other psychiatric disorders were screened through the DSM-5 Structured Clinical Interview (SCID-5) in the patient group. The cases were diagnosed by the researcher-physician through a clinical interview. The adult ADHD groups completed a sociodemographic data form, the Wender Utah Rating Scale (WURS, the short form with 25 items), the Adult ADHD Self-Report Scale Symptom Checklist (ASRS), the Beck Depression Inventory (BDI), and the Beck Anxiety Inventory (BAI). Then, RLS diagnostic criteria were questioned for each patient. The RLS severity scale was used for patients meeting the RLS diagnostic criteria.

Data collection

The sociodemographic data form

The sociodemographic data form, prepared by the researchers, questioned the demographic details and alcohol and substance use by the participants.

Structured Clinical Diagnostic Interview (SCID-5)

SCID is a semi-structured clinical interview for the Diagnostic and Statistical Manual of Mental Disorders — Fifth Edition (DSM-5) diagnoses developed by First 2015 [13]. Turkish validity and reliability studies were conducted by Elbir et al. [14].

Diagnostic interview for ADHD in adults (DIVA)

The DIVA is a semi-structured diagnostic interview based on the DSM-IV diagnostic criteria for adult ADHD [15]. It was translated to the Turkish language by Mukaddes et al. [16]. It consists of three parts, each of which is applied to childhood and adulthood: (1) criteria for attention deficit (A), (2) criteria for hyperactivity/impulsivity (HI), and (3) dysfunction caused by symptoms. For diagnosis, there should be at least two of the functional areas and at least moderate impairment. For the A and HI symptom groups, the criteria in childhood and adulthood are collected separately. If a sufficient number of criteria are met, ADHD is diagnosed, and the predominant clinical picture in the last 6 months is stated.

Adult ADHD Self-Report Scale (ASRS)

The ASRS was developed by the World Health Organization (WHO) to screen adults for ADHD symptoms. The scale consisting of eighteen items is scored between 1 and 4 Likert type [17]. It has two subscales, as attention deficit and hyperactivity/impulsiveness. The validity and reliability of the ASRS in the Turkish language were determined by Doğan et al. [18].

Wender Utah Rating Scale-25 (WURS)

This scale developed by Ward and Wender [19] evaluates the presence and severity of childhood ADHD symptoms in adults. The Turkish validity and reliability study was conducted by Öncü et al. [20]. The WURS is a 5-point Likert type self-report scale consisting of 25 items. Each item is scored between 0 and 4, and the cutoff score of the scale is 36. When the cutoff point is 36 and above, sensitivity was 82.5%, and specificity was 90.8% [20].

Beck Depression Inventory (BDI)

The BDI is a self-evaluation scale of 21 questions, which was developed to measure somatic, emotional, cognitive, motivational, and psychomotor symptoms observed in depression and the level and change in severity of depressive symptoms [21]. Validity and reliability studies have been made on the Turkish form of the scale [22]. The scoring of each item is from 0 to 3 points, and a total score is obtained.

Beck Anxiety Inventory (BAI)

The BAI is a self-evaluation scale of 21 questions each one scored from 0 to 3, which was developed by Beck et al. [23]. Adaptation to Turkish was made by Ulusoy et al. [24]. It is used to determine the level of anxiety and distribution and severity of symptoms. High total points indicate a high level of anxiety.

Assessment of RLS

The diagnosis of RLS is mainly based on clinical history. The 2012 revised International Restless Legs Syndrome Study Group diagnostic criteria (2012 revised IRLSSG diagnostic criteria) were used by the interviewer for the diagnosis of RLS [25]. Five diagnostic criteria focused on the characteristic features of RLS. Patients who meet all criteria are diagnosed with RLS. These are as follows:

1. 1)

   The need to move the legs due to or with uncomfortable or unpleasant sensations in the legs

2. 2)

   The need for movement or uncomfortable sensations begin or worsen at rest.

3. 3)

   The need for movement or uncomfortable sensations are partially or totally relieved by movements such as walking or stretching.

4. 4)

   The need for movement or uncomfortable sensations worsen during the day, in the evening, or at night or occur only in the evening or at night.

5. 5)

   The features listed above cannot be considered solely in relation to primary symptoms or other medical or behavioral conditions (e.g., myalgia, venous stasis, leg edema, leg cramps, habitual foot shaking) [25].

Evaluation of RLS severity

This scale is used to numerically determine the most disturbing symptom and the severity of the disease in RLS. Developed by the International HBS Working Group in 2003, disease severity scale is considered the gold standard. It consists of 10 questions, each graded from 0 to 4. While the first 5 questions are about the severity of the symptoms, the last 5 questions are about the effects of RLS on activities of daily living or quality of life. The score obtained in total reflects the severity of the disease. The maximum score is 40, with 1–10 as mild, 11–20 as moderate, 21–30 as severe, and 31–40 as very severe disease [26].

Statistical analysis

Statistical analyses were performed using SPSS (Version 22.0, SPSS Inc., Chicago, IL, USA, Hitit University Licensed) package program. Descriptive statistics were presented as mean ± standard deviation and median (min-max) and categorical data as number and percentage (%) in accordance with the data distribution. The distribution of normality was analyzed using Kolmogorov-Smirnov and Shapiro-Wilk tests. In comparing the means of two independent samples for continuous variables, the T-test was used for normally distributed data, and the Mann-Whitney U-test was used for non-normally distributed data. In proportion comparisons between categorical variables, the chi-square (chi-square) test or the Fisher’s exact test was used depending on the sample size of the cells in the crosstab. Relationships between numerical variables were analyzed with the Spearman correlation coefficient for non-normally distributed data. Univariate and multivariate binary logistic regression analyses were used to determine the risk factors associated with RLS. Odds ratio (OR) and their 95% CIs calculated for each parameter were found to be statistically significant in logistic regression analysis. Statistical significance was evaluated at p < 0.05.