The last rev­o­lu­tion in the field of psy­chi­a­try be­gan to crys­tal­lize rough­ly 40 years ago, dri­ven by ex­po­nen­tial growth in a class of med­ica­tions known as an­ti­de­pres­sants.¹ While these drugs have of­fered re­lief to mil­lions—they are now pre­scribed to 1 in 7 Amer­i­can adults ² — their ubiq­ui­ty and lack of al­ter­na­tives have in many ways shift­ed the field of psy­chi­a­try to fo­cus on sup­pres­sion of symp­toms through chron­ic med­ica­tion use.

A new era in psy­chi­a­try is emerg­ing—found­ed on promis­ing da­ta that shows phar­ma­ceu­ti­cal psy­che­delics, such as ly­ser­gic acid di­ethy­lamide or LSD, may of­fer a nov­el and pow­er­ful ap­proach to treat men­tal health dis­or­ders, in­clud­ing ma­jor de­pres­sive dis­or­der (MDD) and gen­er­al­ized anx­i­ety dis­or­der (GAD). The re­vi­tal­ized re­search in­ter­est may lead to new FDA-ap­proved ther­a­peu­tic op­tions, po­ten­tial­ly al­low­ing pa­tients to ex­pe­ri­ence durable, last­ing ben­e­fits.

At the fore­front of this re­nais­sance is Defini­um Ther­a­peu­tics (for­mer­ly known as MindMed), a com­pa­ny built on sci­en­tif­ic rig­or and a sin­gu­lar am­bi­tion to trans­form how se­ri­ous men­tal health con­di­tions are treat­ed.

Source: Na­tion­al In­sti­tute of Men­tal Health

The need for in­no­va­tion in this field couldn’t be more ur­gent. Near­ly one in four adults, or rough­ly 59.3 mil­lion peo­ple in the U.S., live with a men­tal health dis­or­der — and over 28 mil­lion do not re­ceive treat­ment.³ And for those who do, cur­rent treat­ments have sig­nif­i­cant lim­i­ta­tions, in­clud­ing chron­ic dai­ly dos­ing, slow on­set of ef­fect, of­ten poor tol­er­a­bil­i­ty, and dif­fi­cul­ty with ad­her­ence, lead­ing to dis­con­tin­u­a­tion.^4,5 Pa­tients can be­come stuck with a sta­tus quo that just isn’t work­ing, leav­ing them want­i­ng more from their treat­ment.

Guid­ed by reg­u­la­to­ry frame­works, and com­mit­ted to sci­en­tif­ic rig­or, Defini­um is de­vel­op­ing in­no­v­a­tive, nov­el ther­a­peu­tics that aim to solve the root caus­es of psy­chi­atric and neu­ro­log­i­cal dis­or­ders and of­fer pa­tients long-term re­mis­sion rather than tem­po­rary symp­tom re­lief.

“We are pow­ered by a rad­i­cal idea: that treat­ments for men­tal health dis­or­ders should bring re­lief,” ex­plains Rob Bar­row, Chief Ex­ec­u­tive Of­fi­cer of Defini­um Ther­a­peu­tics. While this con­cept seems al­most ob­vi­ous, the re­al­i­ty is that the cur­rent im­pact of men­tal health dis­or­ders doesn’t align with the slow pace of progress in ther­a­peu­tic ap­proach­es, un­der­scor­ing an ur­gent need for new, al­ter­na­tive so­lu­tions.

This press­ing de­mand for in­no­va­tion is pre­cise­ly why a grow­ing num­ber of ro­bust clin­i­cal stud­ies are now ex­plor­ing the po­ten­tial of psy­che­delics for men­tal health dis­or­ders. In fact, be­tween 2007 and 2020, 105 psy­che­del­ic clin­i­cal tri­als were reg­is­tered in the U.S., with more than three-quar­ters of those start­ing af­ter 2017.⁶

Fur­ther dif­fer­en­ti­at­ing it­self from oth­er com­pa­nies in the space, Defini­um is tak­ing a nov­el sci­ence-dri­ven ap­proach in their pur­suits to un­lock the clin­i­cal promise of phar­ma­ceu­ti­cal LSD as a trans­for­ma­tive ther­a­peu­tic, in­clud­ing:

• De­liv­er­ing on a late-stage clin­i­cal de­vel­op­ment pro­gram root­ed in ex­cep­tion­al rig­or
• Ad­dress­ing the chal­lenges of com­plex clin­i­cal tri­als head-on through ap­pro­pri­ate con­trol con­di­tions that en­able mean­ing­ful, in­ter­pretable out­comes
• Con­duct­ing three phase 3 stud­ies of LSD in men­tal health dis­or­ders with­out ad­junct psy­chother­a­peu­tic in­ter­ven­tion, with a fourth study ex­pect­ed to ini­ti­ate lat­er this year
• Thought­ful­ly de­sign­ing a treat­ment de­liv­ery mod­el that pri­or­i­tizes safe­ty and ev­i­dence gen­er­a­tion for clin­i­cal tri­als, while plac­ing that ev­i­dence, easy to use as­sess­ment tools, and clin­i­cal judg­ment front and cen­ter

Be­yond the clin­ic, Defini­um re­cent­ly launched an ed­u­ca­tion­al cam­paign called Rerout­ing Minds, aimed at open­ing per­spec­tives by in­creas­ing un­der­stand­ing and pro­vid­ing sci­en­tif­ic con­text around phar­ma­ceu­ti­cal LSD, ex­plor­ing how it may sup­port pos­i­tive men­tal path­ways and last­ing progress in men­tal health care.

LSD₂₅ was an in­ves­ti­ga­tion­al prod­uct of San­doz Lab­o­ra­to­ries. Defini­um Ther­a­peu­tics is not af­fil­i­at­ed with San­doz.

Source: Baquiran M, Keyes D, Al Khalili Y. Ly­ser­gic Acid Di­ethy­lamide Tox­i­c­i­ty; LSD Tox­i­c­i­ty

Re­mark­ably, LSD has a well-doc­u­ment­ed his­to­ry in clin­i­cal re­search. In fact, it is one of the most ex­ten­sive­ly stud­ied psy­chophar­ma­ceu­ti­cals in his­to­ry, with over 1,000 pub­lished re­ports.⁷ LSD was first syn­the­sized in the 1930s by a Swiss chemist named, Al­bert Hof­mann, kick­start­ing years of flour­ish­ing clin­i­cal re­search with the mol­e­cule in the psy­chi­atric space.⁸ But even­tu­al­ly, in the 1960s, com­plex so­ciopo­lit­i­cal and cul­tur­al at­ti­tudes over­shad­owed le­git­i­mate med­ical use and con­tributed to a func­tion­al ban on re­search for LSD — one that per­sist­ed for more than 50 years un­til this new era of psy­che­del­ic re­search emerged in re­cent years.^8,9

“That’s what makes this in­flec­tion point so mean­ing­ful — it’s a mo­ment in which we are re­turn­ing to the ori­gins of the cat­e­go­ry ground­ed in strong sci­en­tif­ic and med­ical rig­or,” Bar­row ex­plains. “We took a decades-old but pow­er­ful phar­ma­ceu­ti­cal in­gre­di­ent, and mod­ern­ized it with cut­ting-edge ap­proach­es to for­mu­la­tion, de­liv­ery, and tri­al pro­to­cols. Near­ly 90 years af­ter it was first for­mu­lat­ed, we are bring­ing LSD back in­to the clin­ic, with all the clin­i­cal and reg­u­la­to­ry stan­dards need­ed to de­vel­op a nov­el phar­ma­ceu­ti­cal prod­uct and rein­spire con­fi­dence.”

As a clas­sic psy­che­del­ic, LSD tem­porar­i­ly al­ters per­cep­tion, cog­ni­tion, and emo­tions, with ex­perts now gen­er­al­ly rec­og­niz­ing it as phys­i­o­log­i­cal­ly safe with­in mod­er­ate dos­es^7,10,11,12 While LS­D's pre­cise mech­a­nism is un­known, it is thought that the tran­sient, psy­cho­log­i­cal ef­fects — me­di­at­ed by ac­ti­va­tion of a sero­tonin re­cep­tor called 5-hy­drox­ytrypt­a­mine 2A (5-HT2A) — and last­ing in­creas­es in neu­ro­plas­tic­i­ty in a va­ri­ety of brain re­gions are po­ten­tial­ly re­spon­si­ble.¹¹

Neu­ro­plas­tic­i­ty — al­so known as neur­al or brain plas­tic­i­ty — is the brain’s re­mark­able ca­pac­i­ty to dy­nam­i­cal­ly rewire it­self, adapt­ing the strength and num­ber of its con­nec­tions through­out a per­son’s life in re­sponse to both in­ter­nal and ex­ter­nal stim­uli.¹³

This fun­da­men­tal con­cept un­der­pins the cam­paign name Rerout­ing Minds, si­mul­ta­ne­ous­ly ref­er­enc­ing LSD’s neu­ro­plas­tic ca­pa­bil­i­ties and aim­ing to re­shape our own per­cep­tions of the mol­e­cule. “We in­vite those in­volved in men­tal health care — doc­tors, psy­chi­a­trists, ther­a­pists, ad­vo­cates, and pol­i­cy­mak­ers — to re­think what’s pos­si­ble about LSD and its po­ten­tial to re­duce suf­fer­ing and im­prove out­comes in cer­tain brain health dis­or­ders,” Bar­row says.

As this new era of psy­che­del­ic re­search con­tin­ues to evolve, Defini­um stands out as the one to watch. Through a de­lib­er­ate and dis­ci­plined ap­proach, Defini­um is work­ing to re­de­fine the bound­aries of men­tal health care — striv­ing to make safe, ef­fec­tive, phar­ma­ceu­ti­cal LSD a re­al­i­ty for pa­tients.

For more in­for­ma­tion, ed­u­ca­tion­al ma­te­ri­als and sci­en­tif­ic re­sources on top­ics in­clud­ing men­tal health gaps, the po­ten­tial of neu­ro­plas­tic­i­ty, a his­to­ry of LSD, and mod­ern re­search ap­proach­es, check out Rerout­ing Minds, here.

Af­ter a down­beat start to 2025, bio­phar­ma struck some high notes in the sec­ond half and end­ed the year with strong Q4 mo­men­tum in deal­mak­ing, fundrais­ing and M&A. The num­bers, once again tracked for us by Chris Doko­ma­ji­lar at Deal­For­ma, help un­der­score a more bull­ish stance in bio­phar­ma that has raised hopes for stronger per­for­mance in 2026 af­ter sev­er­al years of an in­dus­try­wide down­turn.

This past year al­so saw Chi­na biotechs con­sol­i­date their hold on a large por­tion of the glob­al deal­mak­ing be­ing done with Big Phar­ma. And the ma­jor league play­ers came to the ta­ble ready to play with a larg­er bud­get in search of lat­er-stage drugs.