The present study consisted of the study groups including 80 patients with unipolar depression and 80 patients with bipolar depression who applied to the University Psychiatry Clinic, both received treatment from outpatient clinic and were hospitalized, were diagnosed with UD based on DSM-5 as well as 80 healthy volunteers who were not diagnosed with any DSM-5 psychiatric diagnosis as a result of clinical interviews. Patients diagnosed with depression with psychotic traits were not included in the study with patients having unipolar/bipolar depression as they were thought to affect the results of the scales. The first endpoint of the study, which started in April 2020, was reached in February 2021, with a target of reaching 80 patients each with unipolar and bipolar depression. In the statistical analysis performed during the first endpoint, both depression groups were classified into three dimensions according to age using stratified sampling (young < 31, 31–45 = middle age and old > 45). The thresholds for determining stratification in the classification were determined by ensuring homogeneous distribution in both depression groups for all three age groups. It was observed that the number of participants in these three age groups was not statistically significantly different in both groups. Participants in each age dimension were distributed in similar gender ratios in the unipolar and bipolar depression groups. The sample distribution of the healthy control group was planned to consist of 24 young (18 women/6 men), 27 middle-aged (20 women/7 men) and 29 elderly (22 women/7 men) groups after the age and gender categories in the unipolar and bipolar depression groups were summed and divided into two, and the secondary endpoint was completed by obtaining the targeted sample in April 2021 (Fig. 1 shows the flow chart of the study).

Flow chart showing the inclusion of participants

Adults diagnosed with Unipolar/Bipolar Depression and healthy controls were first administered the HDRS, HARS, and YMRS by the researcher and then, the Sociodemographic and Clinical Data Form was completed by the interviewer. The subjects who met the inclusion and exclusion criteria were included in the study and then the CDS and FPMS were completed by the participants. Exclusion criteria were visual-hearing impairment, neurological disease, unstable active medical illness, and history of head trauma, or CNS infection.

Sociodemographic and Clinical Data Form: This form was designed by us to collect socio-demographic and clinical information from the sample and control groups. It was completed by the researcher during the interview with the patients. The form includes data on gender, educational status, marital status, employment status, previous psychiatric admissions, current psychiatric treatments, family history of mental illness, previous suicide attempts, previous psychiatric hospitalizations, age at onset, onset episode, total number of episodes, number of hypomanic, manic, and depressive episodes, age at first depressive episode, and number of days of current illness episode. Measurement of socioeconomic status (SES): Classification was made according to the education and occupational class of the participants, and the Hollingshead index was used as a result of the classification. For scoring, the classification used in the Turkish sample was preferred [7]. To determine socioeconomic groups, five educational levels and five job categories were employed. The lowest level of education and employment received a score of 0, while the greatest received a score of 4. On the basis of the total of scores, three socioeconomic groups were determined, ranging from lowest to highest.

Cognitive Distortions Scale (CDS): The scale was developed by Covin and colleagues [8] and its Turkish validity and reliability study was conducted by Ardanıç [9]. The scale consisted of 10 cognitive distortions(mindreading, catastrophizing, all‐or‐nothing thinking, emotional reasoning, labeling, mental filter, overgeneralization, personalization, should statements, and minimizing the positive), and each item was structured to assess cognitive distortions separately in the interpersonal (IP) and personal achievement (PA) domains. The scale was a self‐report measure. The response options on the scale, which was a7‐point Likert scale, ranged from 1 “Never”to7 “Always.” In the analysis conducted for the internal validity of the scale, Cronbach’s alpha value was reported as 0.85. For the interpersonal (social) and personal achievement subscales, values of 0.75 and 0.79, respectively, were reported.

Frost’s Multidimensional Perfectionism Scale (FMPS): Hewitt and Flett examined perfectionism in three dimensions and developed the 45-item 7-point Likert-type Multidimensional Perfectionism Scale, which is scored between 1 and 7 (1 = Strongly disagree; 7 = Strongly agree) [10]. The scale was adapted into Turkish by Kagan [11]. Hewitt and Flett measure the dimensions of perfectionism in this scale they developed; 1. Self-focused perfectionism (items no. 1, 6, 8, 12, 14, 15, 17, 20, 23, 28, 32, 34, 36, 40, 42), 2. Other-oriented perfectionism (items no. 2, 3, 4, 7, 10, 16, 19, 22, 24, 26, 27, 29, 38, 43, 45) 3. Socially focused perfectionism (items no. 5, 9, 11, 13, 18, 21, 25, 30, 31, 33, 35, 37, 39, 41, 44) [10]. In the study conducted by Kagan, Cronbach's alpha coefficients of the scale were found to be 0.91 for the Self-Oriented Perfectionism sub-scale, 0.73 for the Other-Oriented Perfectionism sub-scale, and 0.80 for the Social-Oriented Perfectionism sub-scale.

Hamilton Depression Rating Scale (HDRS): The original scale prepared by Hamilton has 17 items [12]. Reliability and validity were established in Turkish by Akdemir and colleagues in 1996 (13). In the internal consistency study, Cronbach's alpha value was found to be 0.75 and the reliability coefficient was 0.76.

Hamilton Anxiety Rating Scale (HARS): The scale was developed by Hamilton [13] to determine the level of anxiety and symptom distribution in individuals and to measure the change in severity. Turkish validity and reliability study was conducted by Yazıcı and colleagues in 1998 [14].

Young Mania Rating Scale (YMRS): Young and colleagues developed the mania rating scale (YMRS) in 1978 [15]. The Turkish validity and reliability study of the YMRS was conducted in 2001 by Karadağ and colleagues [16].

Study data were analyzed using SPSS for Windows 25.0 (SPSS Inc, Chicago, IL). The comparison of cognitive distortion and perfectionism variables between the groups was made with one-way variance (ANOVA), Kruskal–Wallis and covariance (ANCOVA) analyses and anxiety scores were determined as covariance. In Post-Hoc evaluations, standardized residual values were used for multiple Chi-square. Tukey comparison test was used when homogeneity of variances was met in ANOVA analysis. In cases where homogeneity of variances was not met in the ANOVA analysis, the Games–Howell comparison test was used, and the Mann–Whitney U test was used in the Kruskal–Wallis analysis. In the current study, the significance level was accepted as p < 0.05.