This study is a cross-sectional study. It was done at the Psychiatry Department, Zagazig University hospitals, during the period from February 2018 to February 2019.
One hundred OCD patients from both genders (aged 18–45 years), with DSM-5 diagnosis of OCD, who fulfilled the inclusion criteria were chosen from both the inpatient ward and the outpatient clinic by simple random sampling.
Assuming that the prevalence of childhood ADHD symptoms in OCD patients is 40% and the rate of admission is 240 cases/year, so the sample size is calculated by Epi Info 6 will be 100 patients (estimated according to confidence interval; C.I) with the a diagnosis of OCD who fulfill the inclusion criteria and will be recruited by systematic random sampling technique until the sample size is reached.
The study included patients of both genders who met DSM-5 criteria for OCD. Their ages ranged from 18 to 45 (in trial to avoid recall bias, also attention deficit symptoms diminished with aging). Full psychiatric examination was held to exclude patients with a history of any other psychiatric disorder.
This study is a cross-sectional study. This study received ethical committee approval from the Department of Psychiatry, Zagazig University, and written informed consent was obtained.
We applied the following assessment procedures to all subjects:
General Medical Examination:
General medical examination of patients was done to exclude the presence of inflammation, severe physical disorders or Organic brain disease.
The Structured Clinical Interview for DSM-5 (SCID 5) to diagnose OCD 
The Hamilton Depression Rating Scale (HDRS)
Clinician-rated scale administrated in 20–30 min to assess the severity of, and change in, depressive symptoms in adults. The HDRS (known also as the HAMD) is considered the most worldwide used scale to assess depression. Seventeen items (HDRS17) form the original version referring to symptoms of depression experienced over the last week. The HDRS was used at first for hospital inpatients and so focus on physical and melancholic symptoms. Scoring varies by version. For the HDRS17, the normal range score is from 0 to 7 (or in clinical remission), a moderate severity score begins from 20 or higher . We used the Arabic version .
Hamilton Anxiety Rating Scale (HARS)
It is a clinician-rated scale providing an analysis of anxiety severity. It is scored based on the rating of 40 individually assessed criteria. Scoring of each item based independently on a 5-point scale. Each question (statement) is answered using a Likert scale, the score of each statement ranges between 0 and 4, 0 refers to not present in the patient and 4 refers to very severe. A total score is calculated by the summation of each of the 14 items. This calculation will yield a comprehensive score in the range from 0 to 5 . We used the Arabic version .
Yale-Brown Obsessive-Compulsive Scale (Y-BOCS)
This scale is utilized to rate the severity of (OCD) symptoms. This scale, which measures compulsions separately from obsessions, measures explicitly the symptoms’ severity of obsessive-compulsive disorder but not being biased about compulsions or obsessions type. It is a self-rating scale containing 10-items; each item rated from 0 to 4 according to the severity of symptoms, yielding a total possible scoring from 0 to 40. Questions ask about the time spent on obsessions, how much distress they have, and how much they can control thoughts. Compulsions are asked about the same questions. The results are analyzed according to the total score: sub-clinical scoring is from 0 to 7, mild is from 8 to 15, moderate is from 16 to 23, severe is from 24 to 31, and extreme is from 32 to 40 . We used the Arabic version .
Barratt Impulsiveness Scale, Version 11 (BIS-11)
The current version of BIS-11 and its predecessors were developed to assess impulsivity. The BIS 11 looks at 3 domains of impulsivity: motor, planning, and attention impulsiveness. The BIS-11 is a self-rating questionnaire with 30 items scored ranging from 1 = rarely/never to 4 = almost always/always. The scoring (total impulsivity score) is as follows: 60–70 mild, 70–80 moderate, and if more than or equal 80 then impulsivity is severe. Administration time is not specified yet estimated to be 10–15 min. The test requires a fifth-grade reading level and is intended for individuals ages 8 and older . We used the Arabic version .
The Wender Utah Rating Scale for the retrospective assessment of symptoms of childhood ADHD
The 61 questions were answered by the adult patient remembering his or her behavior during childhood with five possible answers scored from 0 to 4. The minimum score for 25 questions was 0 and the maximum score was 100. Forty-six refers to a cut-off score, 86 of the ADHD patients, 99 of the normal persons, and 81% of depressed individuals were classified correctly . We used the Arabic version .
The adult ADHD self-report scale Symptom Checklist
It is an instrument including 18 criteria based on DSM-IV-TR. The most predictive symptoms of ADHD were found to be within six questions of the eighteen. Part A contained these six questions. The other 12 questions form Part B. If four or more marks appeared in the dark boxes of Part A, this indicates the patient’s symptoms to be highly consistent with adult ADHD. Part B scoring can serve as a tool to further understand the patient’s symptoms. The six questions consisting Part A are most predictive of the disorder . We used the Arabic version .
After collecting data from all participants
Firstly, to find the frequency of childhood symptoms of ADHD in patients with OCD, among patients with childhood symptoms of ADHD, some with continued symptoms in adulthood, and those who did not, we compared them regarding the severity of depression, anxiety, levels of impulsiveness, and symptom severity.
Also, we compared the same parameters among those who had childhood symptoms of ADHD but not continued symptoms versus those who did not have symptoms since childhood. This was done to assess the effect of childhood symptoms of ADHD even if remitted in adulthood.
Statistical analyses were calculated using version 24 of IBM SPSS Statistics (IBM; Armonk, New York, USA).
Continuous variables were presented as mean ± SD or median (range).
The presentation of categorical variables was by the frequency and percentage.
Levene’s test checked homogeneity of variance.
Shapiro-Wilk test was used to check normality.
Independent samples t test is used to detect the difference between the means of two independent groups on a continuous dependent variable.
Chi-squared test of association can discover the relationship between two categorical variables.
P value (≤ 0.05) was considered a statistically significant difference.