/ eh0f 2680 Mp 431 Thursday Jun 19 05:36 PM EL–PB (v. 61, no. 8) 2680 431 Physiology & Behavior, Vol. 62, No. 2, pp. 431–435, 1997 Copyright  1997 Elsevier Science Inc. Printed in the USA. All rights reserved 0031-9384/97 $17.00 / .00 PII S0031-9384( 97 ) 00035-8 BRIEF COMMUNICATION The Influence of Menstrual-Cycle Phase on the Relationship Between Testosterone and Aggression DONALD M. DOUGHERTY, 1 JAMES M. BJORK, F. GERARD MOELLER AND ALAN C. SWANN Department of Psychiatry & Behavioral Sciences, 1300 Moursund Street, The University of Texas, Houston, TX 77030 USA Received 23 July 1996; Accepted 9 January 1997 DOUGHERTY, D. M., J. M. BJORK, F. G. MOELLER AND A. C. SWANN. The influence of menstrual-cycle phase on the relationship between testosterone and aggression. PHYSIOL BEHAV 62 (2) 431–435, 1997.—Plasma testosterone levels and aggressive behavior were measured in 12 women with and without perimenstrual affective symptomatology ( e.g., depression, irritability ) during the menstrual, midfollicular, ovulatory, and premenstrual phases of the menstrual cycle. The Point Subtraction Aggression Paradigm  was used to quantify aggressive response to provocation. Subjects had two response options: a point- maintained option ( 100 presses earned a point worth 10 cents ) and an aggressive response option ( 10 presses ostensibly subtracted a point from a fictitious partner’s counter). Subjects were provoked by the periodic subtraction of a point that was attributed to the responding of a fictitious opponent. Although plasma testosterone levels ( determined by radioimmunoassay ) increased sig- nificantly during the ovulatory phase, aggressive response to provocation remained unchanged across the menstrual cycle. Plasma testosterone did not differ between the 2 groups during any phase. A relationship between plasma testosterone levels and use of the aggressive response option was seen only during the midfollicular phase (Spearman r Å .673, p Å .017). These preliminary data suggest that: 1. The relationship in female subjects between endogenous testosterone and aggressive behavior is inconsistent; 2. self-report of perimenstrual symptomatology is a more consistent predictor of aggressive behavior across the menstrual cycle than plasma testosterone; and 3. perimenstrual emotional symptomatology is not related to testosterone levels.  1997 Elsevier Science Inc. Aggression Testosterone Menstrual cycle Women 1 To whom requests for reprints should be addressed. Donald M. Dougherty, Ph.D., Department of Psychiatry & Behavioral Sciences, 1300 Moursund Street, Houston, Texas 77030 USA. E-mail: ddoughrt.utmsimail@msi66.msi.uth.tmc.edu NUMEROUS studies have attempted to relate testosterone levels and aggression [ for review, see (1)]. For example, higher tes- tosterone levels have been found in alcoholics with histories of outward-directed aggression than in other alcoholics ( 5 ) , in nor- mal males who act more aggressively when intoxicated ( 29 ) , and in violent prisoners compared to nonviolent prisoners (13,20,27). Male controls studied prospectively showed both a reduction in self-reported aggression following treatment with gonadotropin-releasing hormone antagonists ( 30 ) and increased laboratory-measured aggression following chronic injection of testosterone cypionate (26). The relationship between testosterone levels and aggres- sion in women has not been well-characterized, partially be- cause of concern that the menstrual cycle may confound be- havioral variables (28). Consequently, many behavioral studies have restricted the participation of women to the mid follicular phase, which is thought to be relatively free of af- fective symptoms ( 41 ) . However, because testosterone levels increase at ovulation (22) and in the luteal phase (33), and testosterone levels have been related to cerebrospinal fluid ( CSF ) levels of dopamine and serotonin metabolites ( 23,38 ) , plasma testosterone might relate to aggressive behavior dif- ferently across the menstrual cycle. Aggressive behavior may be quantified in the laboratory using the Point Subtraction Aggression Paradigm (PSAP) (8), an ex- ternally-validated behavioral model that measures a subject’s ag- gressive response to the loss of money. Recent behavioral study of women in our laboratory indicated that women who reported perimenstrual emotional symptoms emitted significantly more aggressive responses in the PSAP than an asymptomatic control