Introduction: Bipolar disorder is a severe and chronic mental illness. Its frequency typically advanced in the general population is 1%. People with this disease may experience manic episodes characterized by an elevated mood, euphoria, and/or depressive episodes characterized by a sad mood, depression. Objective: The aim of this study is the influence of bipolar disorder on the personality of adult Lebanese bipolar patients at cognitive and emotional level. For this purpose, we interviewed about the influence of bipolar disorder on cognition and affectivity of the patient and their possible variation by type I or II of bipolar disorder. Methodology: We collected data on these two factors (cognitive and emotional) of 40 bipolar euthymic adults (between 20 and 40 years) including 21 bipolar I and 19 bipolar II, using the three following questionnaires: the scale of the 'three-dimensional locus of control' of Hannah-Levenson, measuring cognitive style; the Automatic Thoughts Questionnaire of Hollon and Kendall: 'Automatic Thoughts Questionnaire (ATQ), measuring cognitions; the short form of Young Schema Questionnaire: Young Schema Questionnaire-short form (YSQ-S1), measuring the emotional life. Results: Concerning the locus of control, the results show that bipolar II have a score significantly higher on the external scale 'others' than bipolar I. Contrariwise, they resemble at the internal scale and at the external scale 'luck'. Concerning the automatic thoughts, bipolar type I have a higher score but not significant on the Automatic Thoughts Questionnaire then bipolar II. Regarding early maladaptive schemas, the results show the absence of significance between the averages of bipolar I and II, except for one schema: the schema 'entitlement' (exaggerated personal rights) which is higher in bipolar II. Conclusion: Bipolar disorder differently affects the personality of patients at cognitive and emotional level according to type I or II of the disorder. The experience of bipolar type II and their disease according to this study seem to be more deleterious than that of bipolar type I because of their high external locus of control, their negative automatic thoughts and deteriorated early maladjustment patterns that expose them to a high risk of suicide. It appears from our study the importance of psychotherapy in addition to stabilizing treatment in order to treat these psychological parameters, thereby improving the course and prognosis of the disorder.