en Psychiatry Psychiatry Original Research Original Research <p style="text-align: justify;"><strong>Background: </strong>Iran is facing an outbreak of methamphetamine-induced disorders and frequent use of these substances in patients with bipolar disorder. Using or intoxication of methamphetamine in patients with bipolar I disorder may alter the patient&#39;s clinical profile; however there is limited studies about impact of methamphetamine on clinical manifestation of bipolar disorders. This study aimed to compare psychiatric symptoms in patients with bipolar I disorder with and without concomitant use of methamphetamine.</p> <p style="text-align: justify;"><strong>&nbsp; Methods:</strong> In a cross-sectional study, psychiatric symptoms of bipolar I disorder in patients with (Meth+) and without (Meth-) methamphetamine use was evaluated. A number of 57 participants with Meth + and 50 subjects with Meth- were recruited. The clinical picture of bipolar disorder was investigated by Young Mania Rating Scale (YMRS), 17-item Hamilton Depressive Rating Scale (HDRS-17) and the Scale for Assessment of Positive Symptoms (SAPS). Statistical comparisons were performed using the T-test for independent samples and Mann-Whitney test.</p> <p style="text-align: justify;"><strong>&nbsp; Results:</strong> There was no statistically significant difference between two groups regarding age, duration of illness and hospitalizations. However, male participants were significantly higher in Meth+ group than in Meth- one (p<0.001). The mean (&plusmn; SD) scores in the two groups of&nbsp; Meth+ and Meth-&nbsp; for YMRS, HDRS, and SAPS were 31.3 (&plusmn;1.3) and 34.0 (&plusmn;1.2), 13.7 (&plusmn;0.7) and 13.5&plusmn;(0.5), and 50.0 (&plusmn;1.9) and&nbsp; 48.0 (&plusmn;2.1), respectively, which were not statistically significant (p<0.05).</p> <p style="text-align: justify;"><strong>&nbsp;&nbsp;Conclusion:</strong> There was no significant difference in the overall clinical manifestation of bipolar I disorder in patients with and without methamphetamine use. However, in some symptomatology domains, there were some differences between the two groups.</p> Bipolar one disorder, Methamphetamine, Manic episode, Psychosis. 871 879 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-1054&slc_lang=en&sid=1 Elham Gouran Ourimi elhamgouran@gmail.com 200319475328460024553 200319475328460024553 No Department of Psychiatry, Iran University of Medical Science, Tehran, Iran. Amir Shabani shabani.a@iums.ac.ir 200319475328460024554 200319475328460024554 Yes Bipolar Disorders Research Group, Iran University of Medical Sciences, Tehran, Iran. Kaveh Alavi kavehalavi@yahoo.com 200319475328460024555 200319475328460024555 No Mental Health Research Center, Bipolar Disorders Research Group, Iran University of Medical Sciences, Tehran, Iran. Mohammad Reza Najarzadegan najarzadegan2010@gmail.com 200319475328460024556 200319475328460024556 No Department of Psychiatry, Iran University of Medical Science, Tehran, Iran. Fatemehsadat Mirfazeli f.sm6876@gmail.com 200319475328460024557 200319475328460024557 No Department of Psychiatry, Iran University of Medical Science, Tehran, Iran.