In this randomized controlled clinical trial, 50 physically impaired individuals under Welfare Organization support in Qaen city, in 2016, who fulfilled the criteria for entering the study were selected through convenient sampling. Due to the absence of a similar study, a preliminary study was performed on 20 physically disabled patients and the sample size obtained was based on the formula:

At the Type 1 error 5% and Type 2 error 10% in each group of 25 people. After obtaining permission from the Welfare Organization authorities, we consulted the welfare centers in Qaen city. After the goals of the study were explained and informed consent obtained, the demographic characteristics (age, sex, and marital status), Depression, Anxiety, and Stress Scale (DASS-21), and Oxford Happiness Inventory were completed by people with physical impairment through an interview with a facilitator, who had not been informed about the type of intervention. Subjects with a score of less than 40 in the happiness questionnaire were selected and assigned to two groups, the experiment group (25 people) and the control group (25 people), through systematic random sampling. In this process, a draw was conducted between the first two people. Individuals who drew an even number were placed in one group and those who drew odd numbers in the other group. This score was considered as a pre-test score.
The inclusion criteria consisted of an age range of 10 - 40 years, willingness to participate in the study, ability to work with clay, and the use of upper limbs. The exclusion criteria included a history of using anti-depressant and anti-anxiety medicines, severe mental problems (IQ less than 90 based on their records), reluctance to continue to cooperate and attend meetings, and absence in more than two training sessions.
The experiment group received a clay work program for 12 sessions in six weeks (two sessions per week) and each session of 60 minutes (
Table 1).
| Sessions | Contents of Sessions |
|---|
| Session one | Getting acquainted with people in the group, familiarity of the group members with clay work and its techniques, practice for preparation and adaptation to clay work. |
| Session two | Building a tool using Pinch method by members of the group (Pinch is known as the finger method. This method is used without any contact with tools and is as old as the history of working with mud and pottery and is one of the simplest methods). |
| Session three | Building what people in the group think of as monsters. |
| Session four | Making statues of family members |
| Session five | Show fears of the group members by clay |
| Session six | Making a magical form |
| Session seven | Completion of depression and anxiety and stress questionnaire DASS-21and Oxford Happiness Inventory, expressing positive and negative emotions of group members by clay |
| Session eight | Showing objects based on love, making three things that group members like most and making three things they like least. |
| Session nine | Displaying objects based on what they have and what don’t have, making three things that they have more and making three things that they have less. |
| Session ten | Showing feelings of depression and anxiety by clay work |
| Session eleven | Making clay tablets by group members |
| Session twelve | Building a human figure and practicing items related to the previous sessions and observing group rules. |
During the first 15 minutes of the meeting, training on using clay was provided by the researcher, after which the clay work started with simple and small steps, which required less mental and motor skills. After the sixth session and one week after completing the intervention, the questionnaires for depression, anxiety, and happiness were again administered to the subjects of both groups. In order to observe ethical considerations, after the study, a therapeutic clay session was also held for the control group.
The data collection tools were the Depression, Anxiety, and Stress Scales (DASS) and the Oxford Happiness Inventory:
2.1. Depression and Anxiety
DASS-21 questionnaire was first presented by Lovibond and Lovibond (1995) and includes 21 questions that evaluate three components, depression, anxiety, and stress (each component covered by seven questions).
The questions are formulated using a four-point Likert scale ranging from 0, which means “did not apply to me at all,” to 3, which means “applied to me very much or most of the time”. The minimum score in each dimension is zero and the maximum is 21. Asghari Moghdam et al., confirmed the construct validity of this questionnaire by factor analysis (KMO = 0.96 and X
2 = 10318/76). The internal consistency coefficients of the questionnaire for three subscales, depression, anxiety, and stress, were found to be 0.93, 0.90, and 0.92 respectively. With a time interval of three weeks, they were equal to 0.84, 0.89, and 0.90, respectively (
17). In this study, only questions related to the dimensions of depression and anxiety are included.
2.2. Happiness
To measure happiness, the Oxford Happiness Inventory, given by Argyle and Lu (1990), was applied. This scale consists of 29 questions, scored from a = 0 to d = 3, formulated on a four-point Likert scale.
The highest score that a subject can obtain on this scale is 87, which indicates the highest level of happiness. The lowest score is zero, which confirms the subject's dissatisfaction with life and depression. The normal score ranges from 40 to 42. Alipour and Agah Heris confirm the construct validity of this questionnaire by factor analysis (KMO = 0.92 and X
2 = 34161.36) (
18). In a study by Najafi et al. (
19), Cronbach's alpha for Oxford Happiness Inventory was found to be 90%.
Data were entered in the SPSS 15 software and analyzed using Kolmogorov Smirnov test for normal distribution. To compare the qualitative demographic characteristics and the mean age of the two groups, chi-square and independent t tests were applied, respectively.
Considering that the only happiness score had normal distribution in both groups before the intervention, independent t test was used for comparison of the mean. However, the scores of anxiety and depression variables and changes in the scores of different stages did not reflect a normal distribution. Consequently, Mann-Whitney U test was used for comparing the two groups and Friedman test was applied for changes in the three stages. If the result of the test became significant, Wilcoxon test was used for a pairwise comparison. The significance level in all tests is considered 0.05.