EXHIBIT 99.1
NEWS RELEASE



                        PSYCHEMEDICS STOCKHOLDERS APPROVE
                           1 FOR 4 REVERSE STOCK SPLIT


Cambridge, Massachusetts, July 30, 2002 -- Psychemedics Corporation (AMEX: PMD)
today announced that it has received shareholder approval for the one-for-four
reverse split of its common stock. The reverse split had already been approved
by the board of directors.

As of August 1, 2002, each four shares of outstanding common stock of the
company will automatically be converted into one share. In addition, each four
shares of common stock subject to options will be converted into one share. As a
result of the reverse split, the cash dividend recently declared by the Board of
Directors and payable on September 19th to holders of record on September 5th
will now be in the amount of $.08 per share, rather than $.02 per share.

Raymond C. Kubacki, President and Chief Executive Officer of Psychemedics,
noted, "The reverse stock split is an integral element of our strategic
positioning of the Company that will reduce the number of shares from over 20
million to approximately 5 million. The company believes that this action,
together with our improved earnings and dividend increase as recently announced
for the second quarter, better positions Psychemedics to attract coverage from
institutions and professional investors interested in small growth companies."

The reverse split will be effective as of 12:01 a.m. EDT on Thursday, August 1,
2002, and the Company's common stock will begin trading on a post-split basis at
the opening of trading on the American Stock Exchange that same day. Fractional
shares of stock will not be issued as a result of the reverse split.
Stockholders who would otherwise receive a fractional share of common stock will
be entitled to receive an equivalent

amount of cash in lieu of fractional shares, based on the closing price of the
common stock on July 31, 2002. Stockholders will receive instructions by mail
regarding the method of exchanging the old stock certificates for new stock
certificates. EquiServe, LP, is the Company's transfer agent and will act as the
exchange agent for the purpose of implementing the exchange of stock
certificates in relation to the reverse stock split. Psychemedics is the world's
largest provider of hair testing for drugs of abuse with over 2,300 corporations
relying on the patented Psychemedics drug testing services. The Company has THE
ONLY FDA CLEARED HAIR TEST for drugs of abuse. Psychemedics clients include over
10% of the Fortune 500, the six major police departments in America and seven
Federal Reserve Banks.

Cautionary Statement for purposes of the "safe harbor" provisions of the Private
Securities Litigation Reform Act of 1995: From time to time, information
provided by Psychemedics may contain forward-looking information that involves
risks and uncertainties. In particular, statements contained in this release
that are not historical facts (including but not limited to statements
concerning coverage of the company by institutions and professional investors),
may be "forward looking" statements. Actual results may differ from those stated
in any forward-looking statements. Factors that may cause such differences
include, but are not limited to, risks associated with stock market conditions
generally, investor perceptions regarding reverse stock splits, competition and
general economic conditions and other factors disclosed in the Company's filings
with the Securities and Exchange Commission.

The Psychemedics web site is www.drugtestwithhair.com


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