Objective: 

Some neurologic and psychiatric disorders such as schizophrenia, depression, autism and migraine are referred to as cerebral lateralization abnormalities. Therefore, cigarette, alcohol, heroin, hashish and drug addictions may be associated with left-handedness, left-eyedness and crossed hand-eye dominance. In this study the possible relationships among handedness, eye dominance, and crossed hand-eye dominance in patients with different addictions mentioned above are investigated.

Methods: 

Thirty three patients with cigarette, 35 patients with alcohol, 133 patients with heroin, 117 patients with hashish, 13 patients with drug addictions and 102 age matched controls were included in the study. The patient group included 307 men and 24 women who ranged in age from 15 to 70 years. Handedness was ascertained by using the Edinburgh Handedness Inventory. Eye dominance was measured only by the near-far alignment test. Diagnoses were made on the basis of information provided from clinical interviews and Structured Clinical Interview for DSM-IV.

Results: 

Patients with heroin and hashish had a significantly increased frequency of left-handedness in comparison with the other patients and controls (chi square=29.36, p<0.001). Patients with cigarette, alcohol, heroin and hashish addictions had a significantly increased frequency of left-eyedness in comparison with controls (chi square=25.24, p<0.01). Also, patients with cigarette, alcohol, heroin and hashish addictions had a significantly increased frequency of the crossed hand-eye dominance in comparison with controls (chi square=19.11, p<0.01).

Conclusions: 

Different addictions such as cigarette, alcohol, heroin and hashish may be associated with abnormal handedness distribution and accepted as cerebral lateralization abnormalities.