Unfortunately, early researchers made two mistakes when assessing the mental health of homosexual subjects. First, they focused on a population that often truly was mentally ill - inpatients in psychiatric hospitals and individuals who sought out therapy because they were deeply unhappy with their sexual orientation.
The second mistake was an error called "confirmation bias," which occurs when researchers allow their expectations to influence their results. Long-held negative stereotypes about homosexuality led the early psychiatric community to consider gay men and lesbians deeply disturbed. Gay individuals were described with pathological-sounding terms such as "sexual inversion" and "neurotic counterfeit love." Thus, even when psychologically healthy subjects were examined they often were seen as mentally ill.
This began to change when a researcher named Evelyn Hooker conducted a study that avoided both of the pitfalls described above. She used a non-clinical population and conducted the first "blind" study with gay subjects - those interpreting the results did not know whether the subjects they were evaluating were gay or not. The psychiatric community was startled to learn that results from homosexual subects could not be differentiated from those of heterosexual subjects, sparking a series of new investigations.
The following sections review the results of these investigations, including several major psychological tests, and general findings regarding the mental health of gay men and women.
The best known personality tests include the Rorschach Ink Blot Test, the second edition of the Minnesota Multiphasic Personality Inventory (MMPI-2). Additional tests include the Adjective Check List (ACL) and the Sixteen Personality Factor Questionnaire (16PF).
The Rorschach Inkblot Test is one of the oldest and most renowned psychological tests. Testing consists of subjects looking at a series of inkblots and describing what they see in them. These responses are then interpreted to construct a profile of the subject's personality.
Typically the same clinician administers the test and interprets the results. This is usually not a problem, but the possibility of bias exists if the clinician has a strong expectation of certain results. Until the 1950s homosexual subjects had routinely been considered mentally ill, and their test results reflected this expectation. This changed in 1957, when Evelyn Hooker conducted the first blind tests, in which the possibility of bias was removed.
In Hooker's study the Rorschach was administered (along with two other projective tests) to 30 homosexual men and 30 heterosexual men. The results from these administrations were presented to experts in projective test interpretation, but the orientation of the subjects was not disclosed. To the great surprise of the psychiatric community, gay subjects could not be distinguished from straight subjects based on their responses to the tests.
Hooker's study sparked a series of psychological tests with gay subjects to re-evaluate the mental health of gay men and lesbians.
Golding, S.L., & Rorer, L. B. (1972). Illusory correlation and subjective judgement. Journal of Abnormal Psychology, 80, 249-260.
Hooker, E. (1957). The adjustment of the male overt homosexual. Journal of Projective Techniques, 21, 18-31.
Hooker, E. (1958). Male homosexuality in the Rorschach. Journal of Projective Techniques, 23, 278-281.
The second edition of the MMPI, known as the MMPI-2, is a 567-question paper-and-pencil measure of personality. In contrast to the Rorschach, in which a subject's responses require interpretation by a clinician, the MMPI is considered an "objective" measure with a standardized scoring system. Results are presented in terms of 10 clinical scales, such as Social Introversion or Paranoia. One of these scales, the "Mf" (masculinity/femininity) scale, was originally intended to identify gay subjects. Though this scale could not accurately identify a subject's sexual orientation, it does give some indication of whether subjects' gender role behavior is traditional.
Many studies have compared the results of homosexual and heterosexual subjects' results on the MMPI. While some studies have found certain differences between gay and straight subjects, the studies have consistently found that the majority of both groups score in the normal range.
Adelman, M. R. (1977). A comparison of professionally employed lesbians and heterosexual women on the MMPI. Archives of Sexual Behavior, 6, 193-201.
Braaten, L., & Darling, C. (1965). Overt and covert homosexual problems among male college students. Genetic Psychology Monographs, 71, 269-310.
Dean, R. B., & Richardson, H. (1964). Analysis of MMPI profiles of forty college-educated overt male homosexuals. Journal of Consulting Psychology, 28, 483-486.
Horstman, W. R.. (1972). Homosexuality and psychopathology: A study of the MMPI responses of homosexual and heterosexual male college students. Dissertation Abstracts International, 33 (5-13): 2347.
Loney, J. (1971). An MMPI measurement of maladjustment in a sample of normal homosexual males. Journal of Clinical Psychology, 27, 486-488.
Manosevitz, M. (1970). Early sexual behavior in adult homosexual and heterosexual males. Journal of Abnormal Psychology, 76, 396-402.
Manosevitz, M. (1970). Item analysis of the MMPI MF scale using homosexual and heterosexual males. Journal of Consulting and Clinical Psychology, 35, 395-399.
Ohlson, E.L., & Wilson, L. (1974). Differentiating female homosexuals from female heterosexuals by use of the MMPI. Journal of Sex Research, 10, 308-315.
The Adjective Check List asks subjects to endorse whether a series of adjectives accurately describe test-taker. As with other measures of personality, studies have found no large difference between the results from heterosexual and homosexual subjects.
Chang, J., & Block, J. (1960). A study of identification in male homosexuals. Journal of Consulting Psychology, 24, 307-310.
Evans, R. B. (1971). Adjective Check List scores of homosexual men. Journal of Personality Assessment, 35, 344-349.
Hassell, J., & Smith, E. W. (1975). Female homosexual concepts of self, men and women. Journal of Personality Assessment, 39, 154-159.
Thompson, N.L., McCandless, B.R., & Strickland, B.R. (1971). Personal adjustment of male and female homosexuals and heterosexuals. Journal of Abnormal Psychology, 78, 237-240.
The Sixteen Personality Factors Test was developed by Raymond Cattell and his colleagues, and describes individuals by placing sixteen different attributes on a continuum, such as Trusting/Suspicious, Shy/Bold, or Relaxed/Tense. Despite the expectation that gay men and lesbians would appear dramatically different from heterosexuals, the two groups were much closer together than anticipated, and both groups were generally in the normal range of scores.
Evans, R. B. (1970). Sixteen personality factor questionnaire scores of homosexual men. Journal of Consulting and Clinical Psychology, 34, 212-215.
Visser, R. S. (1971). The 16 PF scores of a group of homosexual students. Nederlands Tijdschrift voor de Haarhologie en Haar Grensgebrieden, 26, 159-168.
Bell, A. P., & Weinberg, M. S. (1978). Homosexualities: A Study of Diversity Among Men and Women. New York: Simon & Schuster.
Riess, B. F. (1980). Psychological tests in homosexuality. In J. Marmor (Ed.), Homosexual Behavior, pp. 296-311. New York: Basic Books.
Wilson, M.L., & Green, R. L. (1971). Personality characteristics of female homosexuals. Psychological Reports, 28, 407-412.
A website addressing this issue can be found here.