Iproniazid

 (with 15 g,  orally with 150 mg iproniazid) "this was a daily
   treatment given to schizophrenic patients, tryptophan along with an
   antidepressant which is a monoamine oxidase inhibitor. Most showed
   marked changes such as an elevation in mood, an increased
   involvement with other people in their ward, and an increased
   extrovertism. A separate study of this composition with the addition
   of the amino acid L_methionine produced in about half of these
   patients a toxic or deliriod state."

   ...... Tryptophan, a natural and nutritionally essential amino-acid,
   is a centrally active intoxicant and sleep provider in man. It is
   converted metabolicaly to tryptamine, which is a little bit
   psychedelic.  When administered with methionine (another amino-acid
   know to methylate things) it produces methylated tryptamines, the two
   best studied being N-methyltryptamine (NMT) and N,N-dimethytryptamine
   (DMT). The effects that result are hard to categorize, reflecting the
   the diagnostic state of the patient. But something happens. In short,
   tryptophan, alone or in combination with MAO inhibitors or methyl
   donors, is a fabulous tool for exploring brain function...........

A quick Web search turned up some useful information relating to
methionine (again without permission):

   The Cognitive Enhancement Research Institute
   S-adenosylmethionine (SAM)

   One of the essential metabolic functions of the body is active methyl
   donation (cycle A). The active methylation donor is S-adenosyl-
   methionine (SAM), which is produced from methionine by the addition 
   of ATP (adenosine triphosphate). After the methyl group has been 
   donated (reaction 3), homocysteine remains.  Because homocysteine has 
   pro-oxidant properties (elevated levels are associated with cardio-
   vascular disease), it must be detoxified. Two separate mechanisms 
   exist both of which are serine dependent. In the first (reaction 1), 
   homocysteine is re-methylated by methyltetrahydrofolate (Me-THF, or 
   "activated" folic acid) back to methionine, and the SAM cycle is 
   closed.  Under most circumstances, this should be the dominant 
   pathway. In the second mechanism (reaction 2), homocysteine is 
   combined with serine to form cystathionine which is split back apart 
   (slightly differently) to yield cysteine and homoserine. This 
   reaction depends on the enzyme cystathionine beta-synthase which 
   opens up the SAM cycle and results in loss of methionine (and 
   accumulation of cysteine).

   The restoration of the SAM cycle is not solely dependent on
   increasing serine levels. The folate cycle (cycle B) is essential to
   close the SAM cycle and keep methionine available for producing SAM.

   The folate cycle not only requires folic acid, but also vitamins B6
   and B12, and NADH (a vitamin B3-containing reducing agent). NADH is
   now available as a dietary supplement in the US.

So it appears that to be safe methionine should be taken in combination
with vitamins B12, B6 and folic acid. Again on the down side I have read
that methionine has GI side effects such as nausea.

A safe MAOI could be Peganum harmala extract (harmine). With the
exception of tryptophan all the other ingredients are available from
health food stores.