Adolescence is an essential period in life course which in mental health is at risk. On
the other hand, defense mechanisms that are indicators of mental health have important role in this
issue. It seems that promotion of thought can impress these variables. In this regard, the purpose of
this study was to examine the effect of teaching creative and critical thinking skills on defense styles
and mental health in adolescents attending high school. In an experimental study 40 students who
were selected using random multilayer sampling, were divided into two test and control groups
and responded to DSQ-40 and GHQ in group form. Then, the test group received 10 educational
sessions (20 hours) focusing on thinking skills (creative and critical). The control group didn’t receive
any kind of intervention. Upon completion of educational sessions, both groups were retested with
questionnaires of critical and creativity thinking, thinking. Independent t-tests showed signifi cant
increases in creativity and critical thinking in the experimental group. Furthermore, MANCOVA
showed signifi cant increases in mature defense style (and all of its mechanisms) and on general mental
health. Additionally, a signifi cant decrease were seen in somatic symptoms, anxiety and insomnia,
and severe depression in experimental group.